Whole-Genome Resequencing Revealed Selective Signatures for Growth Traits in Hu and Gangba Sheep.

A genomic study was conducted to uncover the selection signatures in sheep that show extremely significant differences in growth traits under the same breed, age in months, nutrition level, and management practices. Hu sheep from Gansu Province and Gangba sheep from the Tibet Autonomous Region in China were selected. We collected whole-genome data from 40 sheep individuals (24 Hu sheep and 16 Gangba sheep), through whole-genome sequencing. Selection signals were analyzed using parameters such as FST, π ratio, and Tajima's D. We have identified several candidate genes that have undergone strong selection, particularly those associated with growth traits. Specifically, five growth-related genes were identified in both the Hu sheep group (HDAC1, MYH7B, LCK, ACVR1, GNAI2) and the Gangba sheep group (RBBP8, ACSL3, FBXW11, PLAT, CRB1). Additionally, in a genomic region strongly selected in both the Hu and Gangba sheep groups (Chr 22: 51,425,001-51,500,000), the growth-associated gene CYP2E1 was identified, further highlighting the genetic factors influencing growth characteristics in these breeds. This study analyzes the genetic basis for significant differences in sheep phenotypes, identifies candidate genes related to sheep growth traits, lays the foundation for molecular genetic breeding in sheep, and accelerates the genetic improvement in livestock.

Study on aging behavior of polyethylene glycol under three wavelengths of ultraviolet light irradiation.

PEG2000 (polyethylene glycol, molecular weight: 2000) is commonly used for the dehydration and reinforcement of waterlogged wooden cultural relics, but its photo-aging degradation will seriously affect the long-term conservation of the wooden cultural relics. In this study, the photo-aging characteristics and mechanisms of PEG2000 under UV (ultraviolet) irradiations of three wavelengths were comprehensively investigated, and the surface morphology, crystal structure, and relative molecular weight of PEG2000 were systematically characterized. The results showed that PEG2000 showed a higher gloss loss rate, carbonyl index and crystallinity, and a wider molecular weight distribution with increasing aging time, especially under the irradiation of 313 nm ultraviolet light. The evolution of the PEG2000 from surface to interior during photoaging was elucidated by SEM (scanning electron microscopy) and FTIR (Fourier transform infrared spectroscopy), and it was determined that photodegradation not only occurs on the surface of PEG2000 but also gradually extends to the interior of the sample with the prolongation of irradiation time, resulting in the transformation of the basic component unit of spherical crystals in PEG2000 from fibrous crystals to spherical particles. Based on 1H-NMR (nuclear magnetic resonance spectroscopy), the photochemical reactions for the generation of degradation products were proposed, and it was found that the degradation occurred at the C-H and C-O-C bonds on the main chain, forming a large number of ester and ethoxy structures. The aging degree of PEG2000 was evaluated from the perspective of surface morphology and chemical structure by gloss and FTIR spectroscopy, and it was found that the combination of gloss loss rate and carbonyl index was more suitable to evaluate the aging degree of the sample. The relevant theoretical research will provide reliable guidance for the preservation of polyethylene glycol in waterlogged wooden cultural relics.

α-Linolenic acid-regulated testosterone biosynthesis via activation of the JNK-SF-1 signaling pathway in primary rooster Leydig cells.

As a functional fatty acid, α-linolenic acid (ALA) is essential in promoting animal testosterone biosynthesis. This study investigated the effects of ALA on testosterone biosynthesis and the possible mechanism underlying the signaling pathway in primary Leydig cells of the rooster. METHODS: Primary rooster Leydig cells were treated with ALA (0, 20, 40, or 80 µmol/L) or pretreated with a p38 inhibitor (50 µmol/L), a c-Jun NH2-terminal kinase (JNK) inhibitor (20 µmol/L), or an extracellular signal-regulated kinase (ERK) inhibitor (20 µmol/L) before ALA treatment. Testosterone content in the conditioned culture medium was detected using an enzyme-linked immunosorbent assay (ELISA). The expression of steroidogenic enzymes and JNK-SF-1 signaling pathway factors was detected using real-time fluorescence quantitative PCR (qRT-PCR). RESULTS: Supplementation with ALA significantly increased testosterone secretion within culture media (P < 0.05), and the optimized dose was 40 µmol/L. Compared with the control group, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) mRNA expression significantly increased (P < 0.05) in the 40 µmol/L ALA group; 17-hydroxylase/c17-20 lyase (P450c17) and p38 mRNA expressions were not significantly different in the 40 µmol/L ALA group; ERK and JNK mRNA expressions were significantly upregulated (P < 0.05) in 40 µmol/L ALA group. In the inhibitor group, testosterone levels were significantly downregulated (P < 0.05). Compared with the 40 µmol/L ALA group, StAR, P450scc, and P450c17 mRNA expressions were significantly decreased (P < 0.05), and 3ß-HSD mRNA expression in the p38 inhibitor group did not change; StAR, P450scc, and 3ß-HSD mRNA expressions were significantly decreased (P < 0.05), and P450c17 mRNA expression in ERK inhibitor group did not change; StAR, P450scc, 3ß-HSD, and P450c17 mRNA expressions were significantly decreased (P < 0.05) in JNK inhibitor group. Additionally, the increased steroidogenic factor 1 (SF-1) gene expression levels induced by ALA were reversed when the cells were pre-incubated with JNK and ERK inhibitors. The levels in the JNK inhibitor group were significantly lower than those in the control group (P < 0.05). CONCLUSION: ALA may promote testosterone biosynthesis by activating the JNK-SF-1 signaling pathway to upregulate StAR, P450scc, 3ß-HSD, and P450c17 expression in primary rooster Leydig cells.

The Molecular Mechanism of the TEAD1 Gene and miR-410-5p Affect Embryonic Skeletal Muscle Development: A miRNA-Mediated ceRNA Network Analysis.

Muscle development is a complex biological process involving an intricate network of multiple factor interactions. Through the analysis of transcriptome data and molecular biology confirmation, this study aims to reveal the molecular mechanism underlying sheep embryonic skeletal muscle development. The RNA sequencing of embryos was conducted, and microRNA (miRNA)-mediated competitive endogenous RNA (ceRNA) networks were constructed. qRT-PCR, siRNA knockdown, CCK-8 assay, scratch assay, and dual luciferase assay were used to carry out gene function identification. Through the analysis of the ceRNA networks, three miRNAs (miR-493-3p, miR-3959-3p, and miR-410-5p) and three genes (TEAD1, ZBTB34, and POGLUT1) were identified. The qRT-PCR of the DE-miRNAs and genes in the muscle tissues of sheep showed that the expression levels of the TEAD1 gene and miR-410-5p were correlated with the growth rate. The knockdown of the TEAD1 gene by siRNA could significantly inhibit the proliferation of sheep primary embryonic myoblasts, and the expression levels of SLC1A5, FoxO3, MyoD, and Pax7 were significantly downregulated. The targeting relationship between miR-410-5p and the TEAD1 gene was validated by a dual luciferase assay, and miR-410-5p can significantly downregulate the expression of TEAD1 in sheep primary embryonic myoblasts. We proved the regulatory relationship between miR-410-5p and the TEAD1 gene, which was related to the proliferation of sheep embryonic myoblasts. The results provide a reference and molecular basis for understanding the molecular mechanism of embryonic muscle development.

Multi-Omics Analysis Reveals the Potential Effects of Maternal Dietary Restriction on Fetal Muscle Growth and Development.

In terms of fetal muscle growth, development, and health, maternal nutrition is a crucial influence, although the exact biochemical mechanism by which this occurs is still not fully understood. To examine the potential impacts of maternal dietary restriction on fetal muscle development, the sheep maternal dietary restriction model was developed for this study. In our study, 12 pregnant ewes were evenly split into two experimental groups and fed either 75% or 100% of a maternal nutrient. In addition, a multi-omics analysis was used to study the embryonic longissimus dorsis on gestational days (GD) 85 and 135. The fetal weight at GD 135 was significantly below normal due to the maternal restricted diet (p < 0.01). When fetuses were exposed to the dietary deficit, 416 mRNAs and 40 proteins were significantly changed. At GD 85, the multi-omics analysis revealed that maternal dietary restriction led to a significant up-regulation of the cell cycle regulator CDK2 gene in the cellular senescence signaling pathway, and the results of the qRT-PCR were similar to the multi-omics analysis, which showed that SIX1, PAX7, the cell cycle factors CDK4 and CDK6, and the BCL-2 apoptosis factor were up-regulated and several skeletal muscle marker genes, such as MYF5 and MyoD were down-regulated. At GD 135, maternal dietary restriction blocks the muscle fiber differentiation and maturation. The multi-omics analysis revealed that the TEAD1 gene was in the Hippo signaling pathway, the muscle marker genes MYF5 and MyoG were significantly down-regulated, and the TEAD1 binding of the down-regulated VGLL3 gene might be potential mechanisms affecting myofiber differentiation and maturation. Knocking down the CDK2 gene could inhibit the proliferation of primary embryonic myoblasts, and the expression levels of cell cycle regulatory factors CDK4 and CDK6 were significantly changed. Under low nutrient culture conditions, the number of myoblasts decreased and the expression of CDK2, CDK6, MYF5, PAX7 and BCL-2 changed, which was in perfect agreement with the multi-omics analysis. All of the findings from our study helped to clarify the potential effects of maternal dietary restriction on fetal muscle growth and development. They also provided a molecular foundation for understanding the molecular regulatory mechanisms of maternal nutrition on fetal muscle growth and development, as well as for the development of new medications and the management of related metabolic diseases.

Whole-genome resequencing reveals genetic diversity and selection characteristics of dairy goat.

The dairy goat is one of the earliest dairy livestock species, which plays an important role in the economic development, especially for developing countries. With the development of agricultural civilization, dairy goats have been widely distributed across the world. However, few studies have been conducted on the specific characteristics of dairy goat. In this study, we collected the whole-genome data of 89 goat individuals by sequencing 48 goats and employing 41 publicly available goats, including five dairy goat breeds (Saanen, Nubian, Alpine, Toggenburg, and Guanzhong dairy goat; n = 24, 15, 11, 6, 6), and three goat breeds (Guishan goat, Longlin goat, Yunshang Black goat; n = 6, 15, 6). Through compared the genomes of dairy goat and non-dairy goat to analyze genetic diversity and selection characteristics of dairy goat. The results show that the eight goats could be divided into three subgroups of European, African, and Chinese indigenous goat populations, and we also found that Australian Nubian, Toggenburg, and Australian Alpine had the highest linkage disequilibrium, the lowest level of nucleotide diversity, and a higher inbreeding coefficient, indicating that they were strongly artificially selected. In addition, we identified several candidate genes related to the specificity of dairy goat, particularly genes associated with milk production traits (GHR, DGAT2, ELF5, GLYCAM1, ACSBG2, ACSS2), reproduction traits (TSHR, TSHB, PTGS2, ESR2), immunity traits (JAK1, POU2F2, LRRC66). Our results provide not only insights into the evolutionary history and breed characteristics of dairy goat, but also valuable information for the implementation and improvement of dairy goat cross breeding program.

Adaptive Deep Reinforcement Learning-Based In-Loop Filter for VVC.

Deep learning-based in-loop filters have recently demonstrated great improvement for both coding efficiency and subjective quality in video coding. However, most existing deep learning-based in-loop filters tend to develop a sophisticated model in exchange for good performance, and they employ a single network structure to all reconstructed samples, which lack sufficient adaptiveness to the various video content, limiting their performances to some extent. In contrast, this paper proposes an adaptive deep reinforcement learning-based in-loop filter (ARLF) for versatile video coding (VVC). Specifically, we treat the filtering as a decision-making process and employ an agent to select an appropriate network by leveraging recent advances in deep reinforcement learning. To this end, we develop a lightweight backbone and utilize it to design a network set S containing networks with different complexities. Then a simple but efficient agent network is designed to predict the optimal network from S , which makes the model adaptive to various video contents. To improve the robustness of our model, a two-stage training scheme is further proposed to train the agent and tune the network set. The coding tree unit (CTU) is seen as the basic unit for the in-loop filtering processing. A CTU level control flag is applied in the sense of rate-distortion optimization (RDO). Extensive experimental results show that our ARLF approach obtains on average 2.17%, 2.65%, 2.58%, 2.51% under all-intra, low-delay P, low-delay, and random access configurations, respectively. Compared with other deep learning-based methods, the proposed approach can achieve better performance with low computation complexity.

Efficient proton conductivity of a novel 3D open-framework vanadoborate with [V6B20] architectures.

A new three-dimensional (3-D) inorganic metal-oxygen network vanadoborate Na3H10[Ni(H2O)2(VO)6(B10O22)2]·NH4·19H2O (1) constructed from lantern-type {(VO)6(B10O22)2} clusters, NaO6 polyhedra and NiO6 octahedra, was successfully synthesized by a hydrothermal method. In the structure, the {V6B20} clusters are linked together through NiO6 octahedral bridges, resulting in 1-D chains along the c-axis. The 1-D chains are further connected by NaO6 polyhedra to give rise to a 3-D open-framework structure. Furthermore, lots of NH4+ and H2O molecules are accommodated in the void of the structure, and may interact with the [V6B20] system via N-HO, O-HO hydrogen bonds, constructing a complex hydrogen-bonding network system. Strikingly, compound 1 exhibited a high proton conductivity of 3.22 × 10-3 S cm-1 at 50 °C under 100% RH with an activation energy of 1.66 eV.

Enzyme-free and label-free detection of Staphylococcus aureus based on target-inhibited fluorescence signal recovery.

In this work, a one-step fluorometric strategy based on nanometal surface energy transfer (NSET) between carbon dots (CDs) and gold nanoparticles (AuNPs) was developed for facile detection of Staphylococcus aureus (S. aureus). The fluorescence of CDs was quenched up to 63.5% by AuNPs due to nucleic acid hybridization in the presence of linker DNA, which contained the complementary sequences of S. aureus-specific aptamer, and the fluorescence signal was in the "off" state. Upon aptamer addition, the CDs was released from linker DNA through the strong competitiveness of aptamer, leading to the notable fluorescence recovered. Once S. aureus is introduced, aptamer preferentially bind to the bacterial surface and cannot hybridize with complementary sequences in the linker DNA, resulting in the fluorescence signal with "off" state. Based on these findings, the performance and reliability of the fluorescence-based assay were evaluated. Compared to direct hybridization of complementary DNA on the surface of CDs and AuNPs, our sensing strategy has enhanced detection limit (10 cfu⋅mL-1) and improved linear range (10 to 106 cfu⋅mL-1) for S. aureus. Therefore, our proposed enzyme-free and label-free strategy may become a promising method for ease of operation, sensitive and selective S. aureus detection.

A multicolor sensing system for simultaneous detection of four foodborne pathogenic bacteria based on Fe3O4/MnO2 nanocomposites and the etching of gold nanorods.

Food safety problems attributed to foodborne pathogenic bacteria seriously endanger human health and cause substantial economic losses. Novel assays for rapid and sensitive identification of foodborne pathogenic bacteria are highly desired. In this study, a multicolor sensing system has been established for simultaneous determination of four foodborne bacteria by exploiting oxidase mimicking activity of aptamer-functionalized manganese dioxide-coated ferriferrous oxide (apt-Fe3O4/MnO2) nanocomposites and oxTMB etching of gold nanorods (AuNRs). Apt-Fe3O4/MnO2 nanocomposites were used as capture probes to recognize and capture specific bacteria. The captured bacteria blocked the catalytic sites of the magnetic conjugate, which inhibited the catalyzation of oxTMB and further reduced the etching of AuNRs. Consequently, the longitudinal shift of AuNRs decreased linearly with the increase of the concentration of bacteria ranging from 10 to 106 CFU mL-1. Instrumental detection limits for S. aureus, L. monocytogenes, E. coli O157:H7 and V. parahaemolyticus reached down to 1.3 CFU mL-1, 1.2 CFU mL-1, 1.3 CFU mL-1 and 1.4 CFU mL-1, respectively. And their visual detection limit was as low as 10 CFU mL-1. The whole detection process only needs 40 min, suggesting that this method is promising in on-site detection of bacteria.

Layer-by-layer assembly into bulk-like g-C3N4via artificial manipulation of electrostatic forces.

For the first time, bulk-like g-C3N4 was achieved through initiating layer-by-layer assembly, which involves the important process of artificially manipulating protonated and oxygen doped g-C3N4 nanosheets. When acting as a photocatalyst under UV-visible light irradiation, bulk-like g-C3N4 exhibited an excellent photocatalytic H2 production rate of 1538 µmol h-1 g-1, about 8 times higher than that of the bulk g-C3N4 counterpart.

Identification and Comparative Analysis of Long Non-Coding RNA in the Skeletal Muscle of Two Dezhou Donkey Strains.

Long non-coding RNA (lncRNA) has been extensively studied in many livestock. However, compared with other livestock breeds, there is less research regarding donkey lncRNA function. It has been reported that lncRNA plays an important role in the timing control of development, aging, and death of livestock. Therefore, the study of donkey skeletal muscle lncRNA is of great significance for exploring donkey meat production performance. In this study, RNA-Seq was used to perform high-throughput sequencing of skeletal muscle (longissimus dorsi and gluteus) of two Dezhou donkey strains (SanFen and WuTou). The differentially expressed lncRNAs were screened between different strains and tissues. Then candidate genes for conjoint analysis were screened based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Finally, the accuracy of the sequencing data was verified by real-time quantitative polymerase chain reaction (RT-qPCR). Herein, we identified 3869 novel lncRNAs and 73 differentially expressed lncRNAs. Through the comparison between groups, the specific expression of lncRNAs were found in different strains and muscle tissues. Importantly, we constructed the lncRNA-miRNA-mRNA interaction network and found three important candidate lncRNAs (MSTRG.9787.1, MSTRG.3144.1, and MSTRG.9886.1) and four candidate genes (ACTN1, CDON, FMOD, and BMPR1B). Analysis of the KEGG pathway indicates that the TGF-ß signaling pathway plays a pivotal role in the growth and development of skeletal muscle in Dezhou donkey strains.

Dietary supplementation with linseed oil improves semen quality, reproductive hormone, gene and protein expression related to testosterone synthesis in aging layer breeder roosters.

Omega-3/n-3 polyunsaturated fatty acids (ω-3/n-3 PUFAs) play an important role in male reproductive function. The present study was designed to evaluate the effects of linseed oil (LO) as a source of α-linolenic acid (ALA, n-3 PUFA) on semen quality, plasma reproductive hormone and expression of key enzyme and protein related to steroidogenesis in aging layer breeder roosters. Ninety-six 57-wk-old Nongda No.3 layer breeder roosters were randomly assigned into one of four dietary treatments. All birds were fed a basal diet for 1wk and then assigned to a corn-soybean meal-based diet containing 0, 1, 2, 4% LO for 4 wk. After feeding trial, the roosters were slaughtered and investigated. The results showed that semen volume was dramatically increased relative to the other treatments in 2% LO group (P < 0.05). With an increase in dietary LO, semen concentration, sperm viability, sperm motility and total sperm count increased linearly (P < 0.05). Plasma follicle-stimulating hormone (FSH) level increased gradually and reached a maximum when 4% LO was fed (P < 0.01). Plasma luteinizing hormone (LH) levels in 1% and 2% LO group were improved significantly (P < 0.05) relative to the control group. Plasma testosterone (T) levels were remarkably improved compared with the control when birds were fed 2% and 4% LO (P < 0.05). A significant increase of steroidogenic acute regulatory protein (StAR) mRNA expression in 2% and 4% LO group was observed relative to the control group (P < 0.05). An increase in dietary LO supplementation from 1% to 4% markedly enhanced (P < 0.05) the mRNA expression of cholesterol side-chain cleavage enzyme (P450scc) compared to the control. A significant increase (P < 0.05) in the Steroidogenic Factor 1 (SF-1) mRNA levels was observed in the 2% and 4% LO-added groups. SF-1 protein expression was markedly increased by adding LO in diets (P < 0.05), and reached a maximum in 2% LO group. In conclusion, the results above suggest that dietary LO may improve semen quality by increasing the T hormone secretion, which may be related to higher StAR and P450scc mRNA expression and SF-1 expression. These findings provide a potential for using LO to attenuate the age-related sub-fertility in commercial layer breeder roosters.

[Effects of allitridi capsules on endothelial function and clinical prognosis in coronary artery disease patients with obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To explore the effects of allitridi capsules on endothelial function and clinical prognosis in coronary artery disease (CAD) patients with obstructive sleep apnea hypopnea syndrome (OSAHS). METHODS: A total of 80 CAD patients with OSAHS were randomly assigned to receive conventional treatment (control, n = 40) and additional allitridi treatment (120 mg/day, n = 40) for 6 months. Another 40 CAD patients without OSAHS and 30 healthy individuals were chosen as controls. Endothelial function was assessed by endothelium dependent flow-mediated dilation (FMD) with high-definition color Doppler ultrasound. Serum nitric oxide (NO) and plasma endothelin-1 (ET-1) levels were determined by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay. The duration of follow-up was 1 year. RESULTS: The baseline clinical characteristics were not different between control and allitridi groups (P > 0.05). Compared with CAD patients without OSAHS, FMD and serum NO level were significantly lower ((7.9 ± 1.5)% vs (11.2 ± 2.9)%, P = 0.011 and (71.11 ± 10.62) vs (86.28 ± 11.03) µmol/L, P = 0.007), plasma ET-1 level was markedly higher ((112.34 ± 17.22) vs (89.87 ± 11.56) ng/L, P = 0.025) in CAD patients with OSAHS. At Month 6 post-treatment, FMD and serum NO level were significantly higher ((12.1 ± 3.1)% vs (9.1 ± 1.6)%, P = 0.020 and (105.24 ± 17.01) vs (82.39 ± 11.12) µmol/L, P = 0.001) and plasma ET-1 level in the allitridi group was lower ((77.12 ± 9.65) vs (97.77 ± 11.04) ng/L, P = 0.001) than that in the control group. At Month 12 post-treatment, the incidence of MACE was lower in the allitridi group than that in the control group (8.3% vs 15.8%, P = 0.016). CONCLUSION: Allitridi capsules significantly improved endothelial function in CAD patients with OSAHS.

Changes in respiratory and circulatory functions during sequential invasive-noninvasive mechanical ventilation.

OBJECTIVE: To investigate the changes in respiratory and circulatory functions in chronic obstructive pulmonary disease (COPD) patients during sequential invasive-noninvasive mechanical ventilation therapy, and evaluate the effects of this new technique. METHODS: Twelve COPD patients with type II respiratory failure due to severe pulmonary infection were ventilated through an endotracheal tube. When the pulmonary infection control window (PIC-Window) occurred, the patients were extubated and were ventilated with a facial mask using pressure support ventilation combined with positive end-expiratory pressure. The parameters of hemodynamics, oxygen dynamics, and esophageal pressure were measured at the PIC-Window during invasive mechanical ventilation, one hour after oxygen therapy via a naso-tube, and three hours after non-invasive mechanical ventilation. RESULTS: The variation in esophageal pressure was 20.0 +/- 6 cmH(2)O during naso-tube oxygen therapy, and this variation was higher than that during non-invasive mechanical ventilation (10 +/- 6 cmH(2)O, P < 0.01). The changes in respiratory and circulatory parameters were not significantly different between invasive mechanical ventilation and noninvasive mechanical ventilation (P > 0.05). CONCLUSIONS: The respiratory and circulatory functions of COPD patients remained stable during sequential invasive-noninvasive mechanical ventilation therapy using PIC-Window as a switch point for early extubation. The COPD patients can tolerated the transition from invasive mechanical ventilation to noninvasive mechanical ventilation.

Sequential non-invasive mechanical ventilation following short-term invasive mechanical ventilation in COPD induced hypercapnic respiratory failure.

OBJECTIVE: To estimate the feasibility and the efficacy of early extubation and sequential non-invasive mechanical ventilation (MV) in chronic obstructive pulmonary disease (COPD) with exacerbated hypercapnic respiratory failure. METHODS: Twenty-two intubated COPD patients with severe hypercapnic respiratory failure due to pulmonary infection (pneumonia or purulent bronchitis) were involved in the study. At the time of pulmonary infection control window (PIC window) appeared, when pulmonary infection had been significantly controlled (resolution of fever and decrease in purulent sputum, radiographic infiltrations, and leukocytosis) after the antibiotic and the comprehensive therapy, the early extubation was conducted and followed by non-invasive MV via facial mask immediately in 11 cases (study group). Other 11 COPD cases with similar clinical characteristics who continuously received invasive MV after PIC window were recruited as control group. RESULTS: All patients had similar clinical characteristics and gas exchange before treatment, as well as the initiating time and all indices at the time of the PIC window. For study group and control group, the duration of invasive MV was (7.1 +/- 2.9) vs (23.0 +/- 14.0) days, respectively, P < 0.01. The total duration of ventilatory support was (13 +/- 7) vs (23 +/- 14) days, respectively, P < 0.05. The incidence of ventilator associated pneumonia (VAP) were 0/11 vs 6/11, respectively, P < 0.01. The duration of intensive care unit (ICU) stay was (13 +/- 7) vs (26 +/- 14) days, respectively, P < 0.05. CONCLUSIONS: In COPD patients requiring intubation and MV for pulmonary infection and hypercapnic respiratory failure, early extubation followed by non-invasive MV initiated at the point of PIC window significantly decreases the invasive and total durations of ventilatory support, the risk of VAP, and the duration of ICU stay.