3D simulation of percutaneous sustentaculum tali screw insertion in calcaneal fractures.

BACKGROUND: In calcaneal fractures, the percutaneous screw fixation (PSF) is currently considered to be the better choice, but it is difficult to accurately place the screw into the sustentaculum tali (ST) during the operation. In this study, the ideal entry point, angle, diameter and length of the screw were calculated by simulating the operation process. METHODS: We retrospectively collected the calcaneus computed tomography (CT) scans of 180 adults, DICOM-formatted CT-scan images of each patient were imported into Mimics software to establish calcaneus model. Virtual screws were placed on the lateral of the posterior talar articular surface (PTAS), the lateral edge of the anterior process of calcaneus (APC), and the calcaneal tuberosity, respectively, the trajectory and size of the screws were calculated. RESULTS: The mean maximum diameter of the PTAS screw was 42.20 ± 3.71 mm. The vertical distance between the midpoint of the APC optimal screw trajectory and the lowest point of the tarsal sinus was 10.67 ± 1.84 mm, and the distance between the midpoint of the APC optimal screw trajectory and the calcaneocuboid joint was 5 mm ~ 19.81 ± 2.08 mm. The mean maximum lengths of APC screws was 44.69 ± 4.81 mm, and the Angle between the screw and the coronal plane of the calcaneus from proximal to distal was 4.72°±2.15° to 20.52°±3.77°. The optimal point of the maximum diameter of the calcaneal tuberosity screw was located at the lateral border of the achilles tendon endpoint. The mean maximum diameters of calcaneal tuberosity screws was 4.46 ± 0.85 mm, the mean maximum lengths of screws was 65.31 ± 4.76 mm. We found gender-dependent differences for the mean maximum diameter and the maximum length of the three screws. CONCLUSIONS: The study provides effective positioning for percutaneous screw fixation of calcaneal fractures. For safer and more efficient screw placement, we suggest individualised preoperative 3D reconstruction simulations. Further biomechanical studies are needed to verify the function of the screw.

Increased PIT1 and PIT2 Expression in Streptozotocin (STZ)-induced Diabetic Mice Contributes to Uptake of iAs(V).

OBJECTIVE: This study aimed to investigate the susceptibility of mice with streptozotocin(STZ)-induced diabetes mellitus (TIDM) to the uptake of pentavalent inorganic arsenic (iAsV) and the possible molecular mechanism. METHODS: TIDM was induced in mice by STZ. TIDM and normal mice were treated with 15.0 mg/kg Na2HAsO4·12H2O by intragastric administration. Then, the concentrations of arsenic in various tissues were measured by atomic fluorescence spectrometry. The gene expression levels of Pit1 and Pit2 were quantified by real-time RT-PCR, and their protein levels were detected by Western blotting in mouse heart, kidney, and liver tissues. RESULTS: The concentrations of arsenic in STZ-induced TIDM mouse tissues were higher at 2 h after intragastric administration of Na2HAsO4·12H2O. Compared with the levels in normal mice, PIT1 and PIT2, which play a role in the uptake of iAsV, were upregulated in the livers and hearts of TIDM mice. PIT1 but not PIT2 was higher in TIDM mouse kidneys. The upregulation of Pit1 and Pit2 expression could be reversed by insulin treatment. CONCLUSION: The increased uptake of iAsV in TIDM mouse tissues may be associated with increased PIT1 and/or PIT2 expression.

Synthesis, Characterization and Antifungal Evaluation of Novel Thiochromanone Derivatives Containing Indole Skeleton.

Invasive fungal disease constitutes a growing health problem and development of novel antifungal drugs with high potency and selectivity against new fungal molecular targets are urgently needed. In order to develop potent antifungal agents, a novel series of 6-alkyl-indolo[3,2-c]-2H-thiochroman derivatives were synthesized. Microdilution broth method was used to investigate antifungal activity of these compounds. Most of them showed good antifungal activity in vitro. Compound 4o showed the best antifungal activity, which (inhibition of Candida albicans and Cryptococcus neoformans) can be achieved at the concentration of 4 µg/mL. Compounds 4b (inhibition of Cryptococcus neoformans), 4j (inhibition of Cryptococcus neoformans), 4d (inhibition of Candida albicans) and 4h (inhibition of Candida albicans) also showed the best antifungal activity at the concentrations of 4 µg/mL. The molecular interactions between 4o and the N-myristoyltransferase of Candida albicans (PDB ID: 1IYL) were finally investigated through molecular docking. The results indicated that these thiochromanone derivatives containing indole skeleton could serve as promising leads for further optimization as novel antifungal agents.

Evaluation of the horizontal approach to the medial malleolar facet in sagittal talar fractures through dorsiflexion and plantarflexion positions.

BACKGROUND: Talar fractures often require osteotomy during surgery to achieve reduction and screw fixation of the fractured fragments due to limited visualization and operating space of the talar articular surface. The objective of this study was to evaluate the horizontal approach to the medial malleolus facet by maximizing exposure through dorsiflexion and plantarflexion positions. METHODS: In dorsiflexion, plantarflexion, and functional foot positions, we respectively obtained the anterior and posterior edge lines of the projection of the medial malleolus on the medial malleolar facet. The talar model from Mimics was imported into Geomagic software for image refinement. Then Solidworks software was used to segment the medial surface of the talus and extend the edge lines from the three positions to project them onto the "semicircular" base for 2D projection. The exposed area in different positions, the percentage of total area it represents, and the anatomic location of the insertion point at the groove between the anteroposternal protrusions of the medial malleolus were calculated. RESULTS: The mean total area of the "semicircular" region on the medial malleolus surface of the talus was 542.10 ± 80.05 mm2. In the functional position, the exposed mean area of the medial malleolar facet around the medial malleolus both anteriorly and posteriorly was 141.22 ± 24.34 mm2, 167.58 ± 22.36mm2, respectively. In dorsiflexion, the mean area of the posterior aspect of the medial malleolar facet was 366.28 ± 48.12 mm2. In plantarflexion, the mean of the anterior aspect of the medial malleolar facet was 222.70 ± 35.32 mm2. The mean overlap area of unexposed area in both dorsiflexion and plantarflexion was 23.32 ± 5.94 mm2. The mean percentage of the increased exposure area in dorsiflexion and plantarflexion were 36.71 ± 3.25% and 15.13 ± 2.83%. The mean distance from the insertion point to the top of the talar dome was 10.69 ± 1.24 mm, to the medial malleolus facet border of the talar trochlea was 5.61 ± 0.96 mm, and to the tuberosity of the posterior tibiotalar portion of the deltoid ligament complex was 4.53 ± 0.64 mm. CONCLUSIONS: Within the 3D model, we measured the exposed area of the medial malleolus facet in different positions and the anatomic location of the insertion point at the medial malleolus groove. When the foot is in plantarflexion or dorsiflexion, a sufficiently large area and operating space can be exposed during surgery. The data regarding the exposed visualization area and virtual screws need to be combined with clinical experience for safer reduction and fixation of fracture fragments. Further validation of its intraoperative feasibility will require additional clinical research.

Advances in immunotherapy of M2 macrophages and gastrointestinal stromal tumor.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal-derived tumors of the GI tract. They can occur throughout the GI tract, and the survival time of some patients can be improved by first-line targeted therapy with imatinib. However, there are some limitations with imatinib treatment. Immunotherapy for GIST has attracted much attention in recent years, and as one of the most abundant cells in the GIST microenvironment, M2 macrophages play an important role in disease progression. They have unique anti-inflammatory and pro-tumorigenic effects and are one target for immunotherapy. This review summarizes the connection between different factors and the programmed death receptor-1/programmed death ligand-1 pathway and M2 macrophages to reactivate or enhance anti-tumor immunity and improve imatinib efficacy, and to provide new ideas for GIST immunotherapy.

Elevated levels of S100B, tau and pNFH in cerebrospinal fluid are correlated with subtypes of Guillain-Barré syndrome.

Guillain-Barré syndrome (GBS) is an immune-mediated inflammatory disease in the peripheral nervous system. Specific biomarkers for the two most common clinical subtypes of GBS, i.e., acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN) are still missing. The distinctive pathological features of AIDP and AMAN may lead to release of such specific biomarkers including glial markers (calcium-binding astroglial protein, S100B) and axonal damage markers [axoskeletal protein, phosphorylated neurofilament heavy protein (pNFH); cytoskeletal protein, tau], etc. To explore the potentials of biochemical markers for differential diagnosis and evaluation of prognosis of clinical subtypes in GBS, we used ELISA to measure the levels of S100B, tau and pNFH in serum and cerebrospinal fluid (CSF) from the patients with AIDP, AMAN, viral encephalitis and other non-inflammatory neurological disorders (OND), respectively. The values of albumin quotient and IgG index in CSF are significantly higher in AIDP and AMAN than in OND. The levels of S100B, tau and pNFH in serum and CSF are elevated in the patients with AIDP and AMAN compared to OND. The concentrations of these proteins are all higher in CSF than in serum. Increased levels of S100B in CSF at the acute phase are positively correlated with the GBS disability scale scores (GDSs) in AIDP, whereas enhanced levels of tau and pNFH in CSF are positively correlated with the GDSs in AMAN. Increased CSF levels of S100B, tau and pNFH at the acute phase may predict a poor prognosis and evaluate the severity of AIDP or AMAN at plateau and the recovery phase. Elevated levels of pNFH in CSF may be used for differentiating between AMAN and AIDP.

Acute ischemic Stroke combined with Stanford type A aortic dissection: A case report and literature review.

BACKGROUND: Acute aortic dissection (AAD) is a high mortality disease that can lead to acute ischemic strokes (AIS). Some of the patients with AAD combined with AIS initially present with neurological symptoms, which can easily lead to missed or delayed AAD diagnosis. This is attributed to the lack of physician awareness or the urgency of patient thrombolysis. Intravenous administration of thrombolytic therapy (IVT) for AAD is associated with poor prognostic outcomes. We report a patient with AIS combined with AAD who developed a massive cerebral infarction after receiving IVT for a missed AAD diagnosis. CASE SUMMARY: A 49-year-old man was admitted to a local hospital with an acute onset of left-sided limb weakness accompanied by slurred speech. The patient had a history of hypertension that was not regularly treated with medication. Physical examination revealed incomplete mixed aphasia and left limb hemiparesis. Cranial computed tomography (CT) scan showed bilateral basal ganglia and lateral ventricular paraventricular infarct lesions. The patient was diagnosed with AIS and was administered with IVT. After IVT, patient's muscle strength and consciousness deteriorated. From the local hospital, he was referred to our hospital for further treatment. Emergency head and neck CT angiography (CTA) scans were performed. Results showed multiple cerebral infarctions, and aortic dissection in the ascending aorta, innominate artery, as well as in the right common carotid artery. Then, the CTA of thoracoabdominal aorta was performed, which revealed a Stanford type A aortic dissection and aortic dissection extending from the aortic root to the left external iliac artery. Laceration was located in the lesser curvature of the aortic arch. AAD complicated with AIS was considered, and the patient was immediately subjected to cardiovascular surgery for treatment. The next day, the patient underwent aortic arch and ascending aortic replacement and aortic valvuloplasty. CONCLUSION: Clinical manifestations for AAD combined with AIS are diverse. Some patients may not exhibit typical chest or back pains. Therefore, patients should be carefully evaluated to exclude AAD before administering IVT in order to avoid adverse consequences.

[Determination of ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride in maxingshigan decoction by CE].

OBJECTIVE: To establish the method for determination of ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride in maxingshigan decoction by capillary electrophoresis. METHODS: The separation was performed on a fused silica capillary of 60 cm x 55 microcrpm ID (52 cm of effective length). 60 mmol/L NaB4O7 + 10% (V/V) CH3OH (pH 9.0) was selected as the running buffer. The separation voltage was 12 kV. The samples was injected by gravity (10 s, 15 cm). The detection wavelength was 210 nm and berberine hydrochloride was the internal standard. RESULTS: The linear range of determination for ephedrine hydrochloride, pseudoephedrine hydrochloride and methylephedrine hydrochloride were 20.0-160.0 microg/mL (r = 0.9999), 7.5-60.0 microg/mL (r = 0.9991) and 2.0-10.0 microg/mL (r = 0.9993). The average recoveries were 98.0%, 97.0% and 97.8%, the precisions of the method were 2.31%, 2.21% and 2.00% (n=6), respectively. CONCLUSION: The method is convenient, rapid and accurate for the quality control of maxingshigan decoction.

Necroptosis Mediates Cigarette Smoke-Induced Inflammatory Responses in Macrophages.

Introduction: Cigarette smoke (CS)-induced inflammation in macrophages is involved in the pathological process of chronic obstructive pulmonary disease (COPD). Necroptosis, which is a form of programmed necrosis, has a close relationship with robust inflammation, while its roles in COPD are unclear. Materials and Methods: Necroptosis markers were measured in mouse alveolar macrophages and cultured bone marrow-derived macrophages (BMDMs). Necroptosis inhibitors were used to block necroptosis in BMDMs, and inflammatory cytokines were detected. We further explored the related signaling pathways. Results: In this study, we demonstrated the way in which necroptosis, in addition to its upstream and downstream signals, regulates CS-induced inflammatory responses in macrophages. We observed that CS exposure caused a significant increase in the levels of necroptosis markers (receptor interacting kinases [RIPK] 1 and 3) in mouse alveolar macrophages and BMDMs. Pharmacological inhibition of RIPK1 or 3 caused a significant suppression in CS extract (CSE)-induced inflammatory cytokines, chemokine ligands (CXCL) 1 and 2, and interleukin (IL)-6 in BMDMs. CSE-induced necroptosis was regulated by mitochondrial reactive oxygen species (mitoROS), which also promoted inflammation in BMDMs. Furthermore, necroptosis regulated CSE-induced inflammatory responses in BMDMs, most likely through activation of the nuclear factor-κB pathway. Conclusion: Taken together, our results demonstrate that mitoROS-dependent necroptosis is essential for CS-induced inflammation in BMDMs and suggest that inhibition of necroptosis in macrophages may represent effective therapeutic approaches for COPD patients.

Land pavement depresses photosynthesis in urban trees especially under drought stress.

Investigations into the photosynthetic response of urban trees on paved land under drought stress would help to improve the management of trees under rapid urbanization and climate change. An experiment was designed to grow two common greening tree saplings, ash (Fraxinus chinensis Roxb.) and ginkgo (Ginkgo biloba L.), in environments of both land pavement and drought. The results showed that (1) land pavement increased surface and air temperatures and decreased air humidity as well as net photosynthetic rate (Pn) and photosynthetic capacity (Amax) of ginkgo significantly; (2) drought significantly decreased Pn, Amax and maximum net photosynthetic rate (Pnmax) as well as other photosynthetic parameters of both ash and ginkgo; (3) the negative effects of the combination of land pavement and drought on photosynthetic parameters were more significant than the effects of drought treatment for both ash and ginkgo. This implies that urban trees, especially those growing on land pavements, will confront harsher environments and a greater decline of photosynthesis under the severe and more frequent droughts predicted in the future. Overall, ash showed more tolerance to land pavement and drought than ginkgo, indicating that the selection of tolerant tree species is important for urban planting.

[Analysis of River Zooplankton Community Characteristics in Autumn in Beijing].

To clarify the spatial distribution characteristics of zooplankton communities and the relationship between zooplankton and water environmental factors, 81 samples from 28 rivers and lakes in Beijing were collected in September 2017. A total of 68 species of zooplankton were identified, including 17 species of protozoa (25%), 36 species of rotifers (53%), 13 species of cladocera (19%), and copepods (3%, which were mainly copepodids and nauplii). Among 15 dominant species, 12 were copepods and rotifers. Zooplankton communities varied between the different rivers:The zooplankton in rivers in mountainous areas were mainly protozoa and copepods; in suburban areas, communities were dominated by copepods; and in urban areas, rotifers were dominant. A comprehensive water quality index, the Shannon-Wiener index, the Pielou evenness index, and the Margalef richness index were also calculated. Results showed that the water quality of the rivers in mountainous areas was generally better than in urban areas, which was better than in suburban areas. TN was found to be the main form of pollution using the single factor water quality index. Principal component analysis (PCA) and canonical correspondence analysis (CCA) identified that NH4+-N, BOD5, and COD had a significant effect on zooplankton community characteristics.

Spatial pattern of impervious surfaces and their impacts on land surface temperature in Beijing, China.

Land surface temperature (LST), which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces (IS) spatial patterns have on LST in Beijing, China. A classification and regression tree model (CART) was adopted to estimate IS as a continuous variable using Landsat images from two seasons combined with QuickBird. LST was retrieved from the Landsat Thematic Mapper (TM) image to examine the relationships between IS and LST. The results revealed that CART was capable of consistently predicting LST with acceptable accuracy (correlation coefficient of 0.94 and the average error of 8.59%). Spatial patterns of IS exhibited changing gradients across the various urban-rural transects, with LST values showing a concentric shape that increased as you moved from the outskirts towards the downtown areas. Transect analysis also indicated that the changes in both IS and LST patterns were similar at various resolution levels, which suggests a distinct linear relationship between them. Results of correlation analysis further showed that IS tended to be positively correlated with LST, and that the correlation coefficients increased from 0.807 to 0.925 with increases in IS pixel size. The findings identified in this study provide a theoretical basis for improving urban planning efforts to lessen urban temperatures and thus dampen urban heat island effects.

[Mutation analysis of FOXL2 gene and its structure protein in patients of blepharophimosis-ptosis-epicanthus inversus syndrome].

OBJECTIVE: The aim of this study was to investigate the effect of mutations of the forkhead transcription factor 2 (FOXL2) gene on the primary and secondary structure of the coded protein and seek for the molecular mechanism of blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). METHODS: The genomic DNA was extracted from peripheral blood of 7 clinically diagnosed BPES patients, PCR amplification of FOXL2 coding region and 5' untranslated region were performed. Sequence analysis was performed using the PCR or cloning products. The structure of the protein was predicted with PDH and ExPASy software, and the difference between the normal and the mutational protein was analyzed. RESULTS: A 901- 930 dup 30 mutation of FOXL2 was found in two patients from a BPES family of type II and a sporadic case, and no any mutations were detected in normal control. Analysis of the primary structure displayed that the molecular weight of the protein coded by the mutated gene was greater than the normal, but both have the same isoelectric point. Analysis of the secondary structure showed that FOXL2 was a transmembrane protein with a polyalanine tract which contained a alpha-helix. When the polyalanine tract expanded, the helix region extended, as a result, the proportion of alpha-helix increased by 4.1%, but the proportions of beta-pleated sheet and random coil decreased correspondingly. CONCLUSION: Our results suggest that the 901 - 930 dup 30 mutation of FOXL2 is a novel finding. Moreover, this mutation causes great changes in the primary and secondary structure of the coded protein, which may be the molecular pathogenesis of BPES.

[Greenhouse gas emissions, carbon leakage and net carbon sequestration from afforestation and forest management: A review.] / æ£®æž—ç»è¥ä¸Žç®¡ç†ä¸‹çš„æ¸©å®¤æ°”ä½“æŽ’æ”¾ã€ç¢³æ³„æ¼å’Œå‡€å›ºç¢³é‡ç ”ç©¶è¿›å±•.

Forests play an important role in climate change mitigation and concentration of CO2 reduction in the atmosphere. Forest management, especially afforestation and forest protection, could increase carbon stock of forests significantly. Carbon sequestration rate of afforestation ranges from 0.04 to 7.52 t C·hm-2·a-1, while that of forest protection is 0.33-5.20 t C·hm-2·a-1. At the same time, greenhouse gas (GHG) is generated within management boundary due to the production and transportation of the materials consumed in relevant activities of afforestation and forest management. In addition, carbon leakage is also generated outside boundary from activity shifting, market effects and change of environments induced by forest management. In this review, we summarized the definition of emission sources of GHG, monitoring methods, quantity and rate of greenhouse gas emissions within boundary of afforestation and forest management. In addition, types, monitoring methods and quantity of carbon leakage outside boundary of forest management were also analyzed. Based on the reviewed results of carbon sequestration, we introduced greenhouse gas emissions within boundary and carbon leakage, net carbon sequestration as well as the countervailing effects of greenhouse gas emissions and carbon leakage to carbon sequestration. Greenhouse gas emissions within management boundary counteract 0.01%-19.3% of carbon sequestration, and such counteraction could increase to as high as 95% considering carbon leakage. Afforestation and forest management have substantial net carbon sequestration benefits, when only taking direct greenhouse gas emissions within boundary and measurable carbon leakage from activity shifting into consideration. Compared with soil carbon sequestration measures in croplands, afforestation and forest management is more advantageous in net carbon sequestration and has better prospects for application in terms of net mitigation potential. Along with the implementation of the new stage of key ecological stewardship projects in China as well as the concern on carbon benefits brought by projects, it is necessary to make efforts to increase net carbon sequestration via reducing greenhouse gas emissions and carbon leakage. Rational planning before start-up of the projects should be promoted to avoid carbon emissions due to unnecessary consumption of materials and energy. Additionally, strengthening the control and monitoring on greenhouse gas emissions and carbon leakage during the implementation of projects are also advocated.

Enantioselective [3 + 2] Annulation of Enals with 2-Aminoacrylates Catalyzed by N-Heterocyclic Carbene.

A novel and convenient strategy for the enantioselective synthesis of γ-lactam derivatives via N-heterocyclic carbene catalyzed formal [3 + 2] annulation of enals with 2-aminoacrylates is disclosed. This activation mode provides a complementary approach to the synthesis of various γ-lactam derivatives in good yields with excellent diastereo- and enantioselectivities. In this process, two consecutive stereocenters are constructed, and a quaternary carbon center is also established.

Spatial and temporal relationships between precipitation and ANPP of four types of grasslands in northern China.

Precipitation is considered to be the primary resource limiting terrestrial biological activity in water-limited regions. Its overriding effect on the production of grassland is complex. In this paper, field data of 48 sites (including temperate meadow steppe, temperate steppe, temperate desert steppe and alpine meadow) were gathered from 31 published papers and monographs to analyze the relationship between above-ground net primary productivity (ANPP) and precipitation by the method of regression analysis. The results indicated that there was a great difference between spatial pattern and temporal pattern by which precipitation influenced grassland ANPP. Mean annual precipitation (MAP) was the main factor determining spatial distribution of grassland ANPP (r(2) = 0.61, P < 0.01); while temporally, no significant relationship was found between the variance of ANPP and inter-annual precipitation for the four types of grassland. However, after dividing annual precipitation into monthly value and taking time lag effect into account, the study found significant relationships between ANPP and precipitation. For the temperate meadow stcppe, the key variable determining inter-annual change of ANPP was last August May precipitation (r(2) 0.47, P= 0.01); for the temperate steppe, the key variable was July precipitation (r(2)= 0.36, P= 0.02); for the temperate desert steppe, the key variable was April-June precipitation (r(2)=0.51, P< 0.01); for the alpine meadow, the key variable was last September-May precipitation (r(2)= 0.29, P < 0.05). In comparison with analogous research, the study demonstrated that the key factor determining inter-annual changes of grassland ANPP was the cumulative precipitation in certain periods of that year or the previous year.

[Community composition and dynamics of airborne bacteria in Beijing].

Airborne bacteria are important biological components of the aerosol. They have a close relation with human health. The much higher concentrations can result in kinds of microbial disease. Using BIOLOG identification technology, the study on the community structure and dynamics of airborne bacteria was carried out in three typical functional areas in Beijing by systemic site sampling. Results show that the gram positive bacteria contributing 80%-85% were much more than the gram negative bacteria. Amongst 47 genera of bacteria including 31 Gram positive bacteria and 16 Gram negative bacteria, Micrococcus, Staphylococcus, Bacillus, Corynebacterium, and Pseudomonas were dominant, and Micrococcus contributing 20%-30% was the most dominant genus. The concentration of airborne bacteria was significant lower in GGR than in CER and MTL. In a year, the bacterial concentrations of summer and autumn were much more than those of winter and spring in CER and MTL, and there were no significant variations of bacterial concentrations in GGR. In different periods, the lower concentration of airborne bacteria was exhibited at 13:00.

[Estimations of application dosage and greenhouse gas emission of chemical pesticides in staple crops in China.] / æˆ‘å›½ä¸»ç²®ä½œç‰©çš„åŒ–å­¦å†œè¯ç”¨é‡åŠå ¶æ¸©å®¤æ°”ä½“æŽ’æ”¾ä¼°ç®—.

Chemical pesticides play an important role in improving crop yield in modern agriculture. However, commonly overuse of pesticide in China leads to serious environmental problems and food safety hazards. Based on a national questionnaire survey of farmers across China in 2012, the situation of pesticide applications to rice, wheat, and corn in 2011, and their corresponding greenhouse gas (GHG) emissions were investigated. The survey showed that at least 54 types of insecticide, 24 types of fungicide, and 50 types of herbicide were in use across three crops. 32% of rice farmers applied biological pesticides in China. The amounts of pesticides applied to the three cereal crops were 30.8, 16.5, and 58.3 kt for insecticides, fungicides, and herbicides, respectively. The total GHG emission from these pesticides was 1.5 Tg Ce, and the GHG emissions from these insecticides, fungicides, and herbicides accounted for 23.8%, 16.9%, and 59.3% of the total emission, respectively. In south China, the amounts of pesticides applied occupied 51% of the national total. For the production of each kilogram of grain, the amounts of pesticides applied were 0.22, 0.18, and 0.24 g for rice, wheat, and corn, respectively. Therefore, the sums of pesticides applied by crop types were 44.4 kt for rice, 21.4 kt for wheat, and 39.7 kt for corn. Meanwhile, the GHG emissions of pesticides were 665.5, 250.1, and 547.5 Gg Ce for rice, wheat, and corn, respectively. For pesticide types, organophosphorus insecticides accounted for 69% of total insecticide use in China, while benzimidazole, organophosphorus, azole, and organic sulfur fungicides together contributed 87% of total fungicide use. In addition, the use of anilide, organic heterocyclic, and organophosphorus herbicides contributed 85% of the total herbicide application. Therefore, the reduction of pesticide use would play an important role in food safety and environmental safety, and GHG mitigation in agricultural sector in China.