[Whole Process Analysis and Fate Behavior of Microplastics in Urban Wastewater Treatment Plants, Including their Occurrence Forms, Components, and Removal Efficiency].

Microplastics are among the most difficult new pollutants to remove in wastewater treatment plants. In order to explore the occurrence form, size distribution, composition, removal efficiency, migration law, and fate behavior characteristics of microplastic particles in sewage plants, taking a sewage treatment plant in Hohhot as an example, a total of 17 sampling sites were set up. The LAS X software counted the shape, abundance, and size of microplastics and conducted a full-process analysis. The results showed that： fibrous microplastics had the highest abundance and widest distribution and were the main form of existence, accounting for 61.8% of the total abundance； the size of microplastics ranged mainly between 0 and 1.00 mm, and among the four sizes, the abundance of microplastics 0.25 to 0.50 mm in China was the highest, accounting for 32.9%. Among the eight types of plastic components detected, polyester substances （PET, PBT）, cellulose, and polypropylene （PP） were the main components, accounting for 25%, 21%, and 17%, respectively. The influent abundance of the sewage plant was （73 ±5） n·L-1, the effluent abundance was （14 ±2） n·L-1, and the overall removal rate was （80.8 ±12.1）%. Among the three treatment stages of the sewage plant, only the primary treatment played a role in removal, and the abundance of microplastics surged in the secondary treatment. Different structures playing a major role in the removal of microplastics were fine grids （49.2 ±7.4）% and secondary sedimentation tanks （92.4 ±13.9）%. Microplastics mainly existed in the form of fibers, fragments, and films. The proportion of fibers was approximately 70%, and the size of fragments was mainly concentrated between 0.50 and 5.00 mm. Most fragments were in the range of 5.00 mm, accounting for 50%, making them the main form apart from fibrous. The film-like size was mostly concentrated in the range of less than 0.50 mm, accounting for more than 10%. Therefore, improving the removal of small-sized fibrous and film-like microplastics and large-sized fragmented microplastic particles can effectively reduce the pollution risk of microplastics in the environment caused by sewage plant drainage.

[Spatiotemporal Distribution and Source Analysis of Heavy Metals in Surface Sediments in Lake Ulansuhai Based on PCA-APCS-MLR Model].

To explore the spatial and temporal distribution characteristics of heavy metals in the surface sediments of lakes in cold regions during ice-sealing and non-ice-sealing periods, we analyzed the potential ecological risk degree and the pollution sources. A total of 20 sampling sites in Lake Ulansuhai in cold regions were collected from 2020 to 2021, and 120 surface sediment samples were collected during different periods. The contents of As, Cd, Cr, Cu, Ni, Pb, Zn, and Hg were determined. Correlation analysis, principal component analysis, and the absolute factor score-multiple linear regression (APCS-MLR) receptor model were used to trace the source of heavy metal pollution. The results showed that:① the distribution of heavy metals in lake surface sediments was different between the ice-sealing period and the non-ice-sealing period. The distribution of heavy metals during the ice-sealing period was higher in the north and lower in the south. Cd and Hg were mainly distributed in the central and southern lakes during the non-glacial period. ② Hg, Cd, and As were moderately polluted, and Ni was mildly polluted in the surface sediments of the lake. The overall performance was at a high risk level, and the pollution level during the non-ice-sealing period was higher than that during the ice-sealing period. The main environmental risk factors were Hg and Cd, which showed high risk and moderate risk, respectively. ③ The sources of heavy metals in lake surface sediments were mainly industrial sources from mining and transportation, agricultural sources, and natural sources. As, Ni, Pb, and Hg were mainly affected by industrial sources, with contribution rates of 62.67%, 75.31%, 77.47%, and 80.11%, respectively. The main sources of Cu and Zn were natural sources, and Cd was greatly affected by agricultural sources. The contribution rate was 81.57%. The source of Cr was mainly affected by natural factors, and the influence of human activities and unknown sources require further attention.

[Risk Assessment of Heavy Metals in Dust Fall Around Reservoirs in Typical Ecologically Fragile Areas and Traceability Based on APCS-MLR Model].

To assess the health risk status and pollution sources of heavy metals in the atmosphere of ecologically vulnerable areas, the surrounding area of Dahekou Reservoir in Xilingol League was selected as the study area. From 2021 to 2022, 12 monitoring points for atmospheric dust fall were collected for a period of one year. A total of 144 samples were collected to determine the contents of eight types of heavy metals, namely Cr, Ni, Pb, Cu, Zn, Mn, As, and Cd. The potential ecological index (Eri) and health risk assessment model were used to assess the risk level of atmospheric heavy metals on ecological security and human health. The analysis of enrichment factors, principal components, and the model of absolute principal component multiple linear regression (APCS-MLR) receptor were used to analyze the sources of heavy metal pollution qualitatively in the atmosphere of the study area. The results showed that:① the mean value of the comprehensive potential ecological risk of heavy metals in the annual atmospheric dust fall in the study area was at a high ecological risk, and only the Cd value was at a very high risk level among the heavy metals, whereas the remaining were at a slight risk. ② The results of the health risk showed that intake by hand, mouth, and skin contact were the main exposure routes, which led to non-carcinogenic and carcinogenic risks. Children were under non-carcinogenic and acceptable carcinogenic risks in different months. During those months, the main source of the risks was As. ③ Through enrichment factor analysis, principal component analysis, and APCS-MLR receptor model calculation, the results revealed that the proportion of wind-blown sources was the largest, accounting for 37.82%, and the contribution rates of coal combustion and traffic sources to Cu, Cd, Pb, and Zn were 73.01%, 40.22%, 70.31%, and 32.82%, respectively. The contribution rate of mining activities to As was 42.59%, while that of industrial sources of Cd was 22.01%; the contributions of other human activity sources of Cd, As, Pb, and Zn were 21.12%, 34.40%, 23.04%, and 32.15%, respectively.

New technology for preparing energetic materials by nanofiltration membrane (NF): rapid and efficient preparation of high-purity ammonium dinitramide (ADN).

The development of environment-friendly and non-toxic green energetic materials and their safe, environmentally friendly, and economical production is very important to the national economy and national security. As an innovative, efficient, and environmentally friendly energetic material, the preferred preparation method of ammonium dinitramide (ADN) is the nitro-sulfur mixed acid method, which has the advantages of high yield, simple method, and easy access to raw materials. However, the large number of inorganic salt ions introduced by this method limits the large-scale production of ADN. Nanofiltration (NF) has been widely used in various industrial processes as a separation method with high separation efficiency and simple operation. In this study, NF was used for the desalination and purification of ADN synthesized by the mixed acid method. The effects of NF types, operation process (pressure, temperature, and feed solution concentration) on desalination efficiency, and membrane flux during purification were examined. The results showed that 600D NF could achieve the efficient desalination and purification of ADN. It was verified that the highest desalination and purification efficiency was achieved at 2 MPa pressure, 25 °C, and 1 time dilution of the feed solution, and the membrane flux of the desalination and purification process was stable. Under the optimized process conditions, the removal rate of inorganic salts and other impurities reached 99% (which can be recycled), the purity of ADN reached 99.8%, and the recovery rate reached 99%. This process has the potential for the large-scale production of ADN and provides a new process for the safe, efficient, and cheap preparation of energetic materials.

Autophagy benefits the in vitro and in vivo clearance of Talaromyces marneffei.

Talaromycosis, namely Talaromyces marneffei infection, is increasing gradually and has a high mortality rate even under antifungal therapy. Although autophagy acts differently on different pathogens, it is a promising therapeutic strategy. However, information on autophagy in macrophages and animals upon infection by T. marneffei is still limited. Therefore, several models were employed here to investigate the role of autophagy in host defense against T. marneffei, including RAW264.7 macrophages as in vitro models, different types of Caenorhabditis elegans and BALB/c mice as in vivo models. We applied the clinical T. marneffei isolate SUMS0152 in this study. T. marneffei-infected macrophages exhibit increased formation of autophagosomes. Further, macrophage autophagy promoted by rapamycin or Earle's balanced salt solution (EBSS) inhibited the viability of intracellular T. marneffei. In vivo, compared with uninfected Caenorhabditis elegans, the wild-type nematodes upregulated the expression of the autophagy-related gene lgg-1 and atg-18, and nematodes carrying GFP reporter were induced to form autophagosomes (GFP::LGG-1) after T. marneffei infection. Furthermore, the knockdown of lgg-1 significantly reduced the survival rate of T. marneffei-infected nematodes. Likewise, the autophagy activator rapamycin reduced the fungal burden and suppressed lung inflammation in a mouse model of infection. In conclusion, autophagy is essential for host defense against T. marneffei in vitro and in vivo. Therefore, autophagy may be an attractive target for developing new therapeutics to treat talaromycosis.

[Proventive and Therapentic Effects of Endothelial Progenitor Cells on Monocrotaline-Induced Hepatic Vein Occlusion Disease].

OBJECTIVE: To investigate the preventive and therapeutic effects of endothelial progenitor cells on monocrotaline-induced hepatic vein occlusion disease in mice. METHODS: C57BL/6 mice were randomly divided into 3 groups: saline group (n=15), monocrotaline group (n=15), and endothelial progenitor cell infusion group (n=15). Liver function (TBIL, ALT, AST), liver index, and serum levels of TNF-α and IL-6 were measured on the 8th day after intragastric administration. Hepatic sinusoidal endothelial cells, hepatic central venous endothelial cells and hepatocytes were observed by both HE and immunohistochemical staining. Hepatic fibrosis was observed by Masson's trichrome staining. RESULTS: By the light microscopy, the liver of the monocrotaline group showed moderate to the severe injuries of hepatic sinusoidal and central venous endothelial cells, and hepatic venous congestion. Masson staining showed moderate to severe hepatic fibrosis of central vein and hepatic sinus. In the endothelial progenitor cell group, hepatic sinusoidal and central venous endothelial cell injuries, and the fibrosis of central hepatic vein and hepatic sinus were mild to moderate. Hepatic venous congestion was reduced in comparison with that in the mice of the monocrotaline group. Compared with the endothelial progenitor cell group, the liver index was higher, the liver function was more abnormal, and the serum expression levels of TNF-α and IL-6 were higher in the monocrotaline group. CONCLUSION: The monocrotaline-induced damage of hepatic sinusoidal and central venous endothelial cells is an linitiating factor for hepatic vein occlusive disease. Infusion of endothelial progenitor cells can play a role in preventing and treating hepatic vein occlusion.

Identification of potential therapeutic target genes in mouse mesangial cells associated with diabetic nephropathy using bioinformatics analysis.

The aim of the present study was to identify genes under the effect of transforming growth factor-ß (TGF-ß1), high glucose (HG) and glucosamine (GlcN) in MES-13 mesangial cells and elucidate the molecular mechanisms of diabetic nephropathy (DN). The gene expression datasets GSE2557 and GSE2558 were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were independently screened using the GEO2R online tool. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the Database for Annotation, Visualization, and Integrated Discovery. The protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes and Cytoscape software. The hub genes were identified by the NetworkAnalyzer plugin. Overlapping genes were subjected to molecular docking analysis using SystemsDock. A total of 202 upregulated and 158 downregulated DEGs from the HG-treated groups, 138 upregulated and 103 downregulated DEGs from the GlcN-treated groups, and 81 upregulated and 44 downregulated DEGs from the TGF-ß1-treated groups were identified. The majority of the DEGs were independently enriched in 'nucleosome assembly', 'chromatin silencing' and 'xenobiotic glucuronidation'. In addition, KEGG pathways were significantly enriched in 'systemic lupus erythematosus', 'protein processing in endoplasmic reticulum' and 'aldarate metabolism pathway', and 'TNF signaling pathway' intersected in the TGF-ß1-treated and HG-treated groups. In total, eight hub genes, Jun, prostaglandin-endoperoxide synthase 2 (Ptgs2), fibronectin 1 (Fn1), cyclin-dependent kinase (Cdk)2, Fos, heat shock protein family A (Hsp70) member 5 (Hspa5), Hsp90b1 and homo sapiens hypoxia upregulated 1 (Hyou1), and three overlapping genes, Ras homolog gene family, member B (RHOB), complement factor H (CFH) and Krüppel-like factor 15 (KLF15), were selected. Valsartan with RHOB, and fosinopril with CFH and KLF15 had preferential binding activity. In conclusion, Jun, Ptgs2, Fn1, Cdk2, Fos, Hspa5, Hsp90b1, Hyou1, RHOB, CFH and KLF15 may be potential therapeutic targets for mesangial cells associated with DN, which may provide insight into DN treatment strategies.

[Mechanism of effective components of Mori Folium in alleviating insulin resistance based on JNK signaling pathway].

A stable hepatoma cell line(Hep G2 cell) insulin resistance model was established and used to analyze the effect of effective components of Mori Folium in alleviating insulin resistance,and preliminary explore the mechanism for alleviating insulin resistance. The Hep G2 insulin action concentration and the duration of action were investigated using the glucose oxidase method(GOD-POD method) to establish a stable Hep G2 insulin resistance model. Normal control group,model group,Mori Folium polysaccharide group,Mori Folium flavonoid group and rosiglitazone group were divided to determine the glucose consumption. The effect of Mori Folium effective components on Hep G2 insulin resistance was analyzed. The mRNA expressions of JNK,IRS-1 and PDX-1 in each group were detected by Real-time quantitative PCR(qRT-PCR). The protein expressions of p-JNK,IRS-1 and PDX-1 were detected by Western blot. And the mechanism of effective components of Mori Folium in alleviating insulin resistance was investigated. The results showed that the glucose consumption was significantly decreased in the insulin resistance cells after incubation with 25. 0 mg·L-1 insulin for 36 h(P<0. 01),and the model was relatively stable within 36 h. Mori Folium polysaccharides and flavonoids all alleviated insulin resistance,among which Mori Folium flavonoids had better effect in alleviating Hep G2 insulin resistance(P<0. 05). The qRT-PCR analysis showed that Mori Folium polysaccharides and flavonoids could inhibit JNK and IRS-1 mRNA expressions,while enhancing PDX-1 mRNA expression. Western blot analysis displayed that Mori Folium polysaccharides and flavonoids could inhibit p-JNK and IRS-1 protein expressions,while enhancing PDX-1 protein expression. Mori Folium polysaccharides and flavonoids can alleviate insulin resistance in Hep G2 cells,and its mechanism may be the alleviation of insulin resistance by inhibiting JNK signaling pathway.

The relationship between preoperative psychological evaluation and compensatory sweating.

BACKGROUND: This study analyzes the relationship between preoperative psychological states of primary palmar hyperhidrosis patients and postoperative compensatory sweating. METHODS: We evaluated the psychological states of patients with primary palmar hyperhidrosis who received sympathectomy in our hospital from 2016 to 2017. The relationship between preoperative psychological states and postoperative compensatory sweating were assessed using Spearman's rank-order correlation. RESULTS: Fifty-five patients who received R4 + R3 bypass transection accepted the preoperative questionnaire survey; 35 were males and 20 were females. The average age was 24.0 ± 6.3 years (range, 14-44 years). Depression symptoms were present in 21.9% (12/55) of the patients; the incidence of anxiety was almost similar, at 23.7% (13/55). Compensatory sweating occurred in 67.3% (37/55) of the patients; of these, 56.4% (31/55) was mild and 10.9% (6/55) was moderate. None of the patients had severe compensatory sweating. There was no significant relationship between the scores of SDS, SAS, and the incidence of postoperative compensatory sweating (P>0.05). However, the psychoticism scale displayed a strong impact on the degree of compensatory sweating (P<0.05). The higher the degree of psychoticism scale, the more serious the degree of compensatory sweating. CONCLUSIONS: The results of this study showed that patients with primary palmar hyperhidrosis are more likely to have mild or moderate mental disorders, and that postoperative compensatory sweating may impact the satisfaction of surgery. In addition, the personality characteristics of patients are related to compensatory sweating.

Extraction of flavonoids from Chrysanthemum morifolium and antitumor activity in vitro.

The aim of the present study was to optimize flavonoid extraction from Chrysanthemum morifolium and to study the antitumor effects of flavonoids on human gastric cancer MKN45 cells in vitro. A single factor experiment was designed and the extraction process was optimized using an orthogonal test. MKN45 cells were treated with different concentrations of flavonoid from Chrysanthemum morifolium for 24 and 48 h and the inhibitory effect on the MKN45 cells was evaluated using an MTT assay. Following staining with Annexin V-fluorescein isothiocyanate/propidium iodide, flow cytometry was performed. The optimized flavonoid extraction conditions were as follows: Duration of ultrasonic treatment: 35 min; ethanol concentration: 75%; extraction temperature: 80°Cand liquid-to-solid ratio 25: 1. Under the above conditions, the extraction rate of flavonoids was 5.24%. When compared with a blank control group, flavonoids extracted from Chrysanthemum morifolium inhibited the proliferation of MKN45 cells in a dose- and time-dependent manner. Furthermore, in cell groups treated with low, moderate and high concentrations of flavonoid, it was observed that the proportion of apoptotic cells increased in a dose-dependent manner. The extraction process optimized by the orthogonal test achieved a high yield and satisfactory extraction efficiency. Additionally, the experiment demonstrated that flavonoids from Chrysanthemum morifolium inhibited the growth of MKN45 cells and induced their apoptosis. Thus, flavonoids from Chrysanthemum morifolium exerted antitumor effects on MKN45 cells, which may be exploited as a potential antitumor therapeutic for gastric cancer.

Ultrasound assisted extraction of polysaccharides from Lentinus edodes and its anti-hepatitis B activity in vitro.

The aim of this study was to optimize the extraction process of polysaccharides from the fruiting bodies of Lentinus edodes and investigate its anti-hepatitis B virus activity. The extracting parameters including ultrasonic power (240-320W), extraction temperature (40-60°C) and extraction time (15-25min) was optimized by using three-variable-three-level Box-Behnken design based on the single-factor experiments. Data analysis results showed that the optimal conditions for extracting LEPs were an extraction temperature of 45°C, extraction time of 21min and ultrasonic power of 290W. Under these optimal conditions, the experimental yield of LEPs was 9.75%, a 1.62-fold increase compared with conventional heat water extraction (HWE). In addition, crude polysaccharides were purified to obtain two fractions (LEP-1 and LEP-2). Chemical analysis showed that these components were rich in glucose, arabinose and mannose. Furthermore, HepG2.2.15 cells were used as in vitro models to evaluate their anti-hepatitis B virus (HBV) activity. The results suggest that LEPs possesses potent anti-HBV activity in vitro.

Room temperature continuous wave quantum dot cascade laser emitting at 7.2 µm.

We demonstrate a quantum cascade laser with active regions consisting of InAs quantum dots deposited on GaAs buffer layers that are embedded in InGaAs wells confined by InAlAs barriers. Continuous wave room temperature lasing at the wavelength of 7.2 µm has been demonstrated with the threshold current density as low as 1.89 kA/cm2, while in pulsed operational mode lasing at temperatures as high as 110 °C had been observed. A phenomenological theory explaining the improved performance due to weak localization of states had been formulated.

High efficiency, single-lobe surface-emitting DFB/DBR quantum cascade lasers.

We demonstrate a surface-emitting quantum cascade laser (QCL) based on second-order buried distributed feedback/distributed Bragg reflector (DFB/DBR) gratings for feedback and outcoupling. The grating fabricated beneath the waveguide was found to fundamentally favor lasing in symmetric mode either through analysis or experiment. Single-lobe far-field radiation pattern with full width at half maximum (FWHM) of 0.18° was obtained along the cavity-length direction. Besides, the buried DFB/DBR grating structure successfully provided an efficient vertical outcoupling mechanism with low optical losses, which manages to achieve a high surface outcouping efficiency of 46% in continuous-wave (CW) operation and 60% in pulsed operation at room temperature. Single-mode emission with a side-mode suppression ratio (SMSR) about 25 dB was continuously tunable by heat sink temperature or injection current. Our work contributes to the realization of high efficiency surface-emitting devices with high far-field beam quality that are significantly needed in many application fields.

Optimization of cellulase-assisted extraction process and antioxidant activities of polysaccharides from Tricholoma mongolicum Imai.

BACKGROUND: Tricholoma mongolicum Imai is a well-known edible and medicinal mushroom which in recent years has attracted increasing attention because of its bioactivities. In this study, water-soluble polysaccharides were extracted from T. mongolicum Imai by cellulase-assisted extraction and their antioxidant activities were investigated. RESULTS: In order to improve the yield of polysaccharides, four variables, cellulase amount (X1 ), pH (X2 ), temperature (X3 ) and extraction time (X4 ), were investigated with a Box-Behnken design. The optimal conditions were predicted to be cellulase amount of 20 g kg(-1) , pH of 4.0, temperature of 50 °C and extraction time of 127 min, with a predicted polysaccharide yield of 190.1 g kg(-1) . The actual yield of polysaccharides under these conditions was 189.6 g kg(-1) , which matched the predicted value well. The crude polysaccharides were purified to obtain four fractions, and characterization of each was carried out. In addition, antioxidant properties of four polysaccharides assessed by 1,1-diphenyl-2-picryldydrazyl (DPPH) and hydroxyl radical-scavenging assays indicated that polysaccharides from T. mongolicum Imai (TMIPs) possessed antioxidant activity in a dose-dependent manner. CONCLUSION: TMIPs show moderate antioxidant activities in vitro. Therefore it is suggested that TMIPs are potential natural antioxidants for use in functional foods. © 2016 Society of Chemical Industry.

Serum TGF-ß1 as a Biomarker for Type 2 Diabetic Nephropathy: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Abnormal expression of serum TGF-ß1 was found in patients with diabetic nephropathy. However, the association of TGF-ß1 with the risk of diabetic nephropathy remains unknown. The present study was undertaken to investigate whether such an association exists. METHODS: We searched the Chinese VIP, Wangfang, China National Knowledge Infrastructure, PubMed, Embase, and Google Scholar databases for relevant studies and extracted all eligible data. Stata12 software was used for statistical analysis. RESULTS: Nine reports met our criteria and were used for data extraction. There were 264 patients and 227 healthy controls from qualified reports in this meta-analysis. The results suggested that serum TGF-ß1 levels were significantly up-regulated in patients with diabetic nephropathy; the instrumental variable was 3.94 (95% confidence interval 3.20-4.68, p<0.01). CONCLUSIONS: Meta-analysis suggested that elevated serum TGF-ß level in patients with diabetes is associated with a high risk of nephropathy. Further studies are required to validate these observations.

[Microbial community structure of the alpine meadow under different grazing styles in Naqu prefecture of Tibet].

To clarify the effects of grazing styles on the soil microbial community in the alpine meadow, we explored the changes of soil microbial community structure in the alpine meadow located in Naqu district of Tibet Autonomous Region by analyzing the soil chemical properties and phospholipid fatty acids (PLFAs). The results showed that the contents of soil total organic carbon, total phosphate and nitrate nitrogen under the different grazing styles followed the trend of 7-year rest grazing > free grazing > grazing prohibition. Except for the ratio of fungal PLFAs/bacterial PLFAs, total PLFAs, the bacterial PLFAs, the fungal PLFAs, the gram negative bacterial and the gram positive bacterial PLFAs over the different grazing types were in the order of 7-year rest grazing > 5-year grazing prohibition > 7-year and 9-year grazing prohibition. The principal component analysis (PCA) presented that the first principal component (PC1 = 74.6%) was mainly composed of monounsaturated fatty acids, polyunsaturated fatty acids and branched fatty acids, and the second principal component (PC2 = 13.2%) was mainly composed of saturated fatty acids and some monounsaturated fatty acids. Total PLFAs content was significantly positively correlated with microbial biomass carbon content. Compared with grazing prohibition, fallow grazing was best for the alpine meadow in Naqu district, and free grazing with light intensity was good for the alpine meadow.

10-W pulsed operation of substrate emitting photonic-crystal quantum cascade laser with very small divergence.

High-power broad area substrate emitting photonic-crystal distributed feedback (DFB) quantum cascade lasers (QCLs) emitting around 4.73 µm is reported. Two-dimensional centered rectangular photonic-crystal (CRPC) grating is introduced to enhance optical coherence in large area device. Main lobe far-field radiation pattern with a very small divergence angle of about 0.65° × 0.31° is obtained. A record peak output power for vertical emitting QCLs exceeding 10 W is obtained with high reflectivity (HR) coating. Robust single longitudinal mode emission with a side mode suppression ratio (SMSR) of 30 dB is continuously tunable by the heat sink temperature up to 65°C.

Small divergence substrate emitting quantum cascade laser by subwavelength metallic grating.

Metallic periodic structure in subwavelength scale offers an exciting way to couple light into surface plasmons (SPs), thus manipulating the properties of near-field optics. We show that subwavelength metallic grating (SMG) defined on the substrate side of substrate emitting quantum cascade lasers enables far-field improvement in mid-infrared spectrum. The SMG is designed to tailor the interaction of SPs with single mode transverse magnetic light. The experiment results are in good agreement with the simulated model. A far-field full width at half maximum (FWHM) divergence angle of 3.9 ° in the direction perpendicular to the laser waveguide layers is obtained, improved by a factor of 8.5 compared with traditional surface emitting device.