The preparation of polysilicon films on highly boron doped silicon substrates and their effects on Cu out-diffusion.

The behavior of copper (Cu) diffusion at different storage temperatures of heavily boron-doped silicon substrates is investigated. The surface Cu concentration of the substrate with quantitative Cu contamination exhibits an initial increase followed by a subsequent decrease upon storage at 25 °C and 85 °C. The surface Cu, originating from the out-diffusion, can be effectively removed through RCA cleaning. The polysilicon film, prepared by low-pressure chemical vapor deposition (LPCVD) on the back of the substrate, exhibits a pronounced inhibitory effect on the out-diffusion of Cu. This phenomenon can be attributed to the effective gettering of Cu by both grain boundaries and disordered grain structures within the polycrystalline silicon film. Additionally, the multilayered structure of the polysilicon film exhibits enhanced gettering capabilities. The enhanced gettering effectiveness achieved by the multilayer polysilicon film can be attributed to an increased number of interfaces between layers.

Regulating Au coverage for the direct oxidation of methane to methanol.

The direct oxidation of methane to methanol under mild conditions is challenging owing to its inadequate activity and low selectivity. A key objective is improving the selective oxidation of the first carbon-hydrogen bond of methane, while inhibiting the oxidation of the remaining carbon-hydrogen bonds to ensure high yield and selectivity of methanol. Here we design ultrathin PdxAuy nanosheets and revealed a volcano-type relationship between the binding strength of hydroxyl radical on the catalyst surface and catalytic performance using experimental and density functional theory results. Our investigations indicate a trade-off relationship between the reaction-triggering and reaction-conversion steps in the reaction process. The optimized Pd3Au1 nanosheets exhibits a methanol production rate of 147.8 millimoles per gram of Pd per hour, with a selectivity of 98% at 70 °C, representing one of the most efficient catalysts for the direct oxidation of methane to methanol.

Heterojunction Engineering of Multinary Metal Sulfide-Based Photocatalysts for Efficient Photocatalytic Hydrogen Evolution.

Photocatalytic hydrogen evolution (PHE) via water splitting using semiconductor photocatalysts is an effective path to solve the current energy crisis and environmental pollution. Heterojunction photocatalysts, containing two or more semiconductors, exhibit better PHE rates than those with only one semiconductor owing to the altered band alignment at the interface and stronger driving force for charge separation. Traditional binary metal sulfide (BMS)-based heterojunction photocatalysts, such as CdS, MoS2 , and PbS, demonstrate excellent PHE performance. However, the recently developed multinary metal sulfide (MMS)-based photocatalysts possess favorable chemical stability, tunable band structure, and flexible element compositions, and have considerable potential to realize higher PHE rates than those of BMSs. In this review article, the mechanism of PHE is first elucidated and then various single and heterojunction MMS-based photocatalysts and their charge transfer behaviors and PHE performances are systematically summarized. A perspective on potential future research directions in this field is concluded.

Synthesis of the 5-6-7 Tricyclic Core of Daphnicyclidin-Type Alkaloids via a Tiffeneau-Demjanov Ring Enlargement Strategy.

An expedient construction of the 5-6-7 tricyclic core of daphnicyclidin-type alkaloids is described. The synthetically challenging cycloheptanone C ring was constructed via a Tiffeneau-Demjanov ring enlargement reaction from a 5-6-6 tricyclic precursor commonly found in calyciphylline A-type alkaloids. Other key transformations included Davis oxidation, 1,2-addition, oxidation, and dehydration to elaborate the essential cyclcohept-2-enone motif.

Differentiation of bladder cancer stages using the vesical imaging -reporting and data system and apparent diffusion coefficient.

Background: T stage is closely related to the treatment and prognosis of patients with bladder cancer (BC). However, preoperative T staging is still challenging. Multiparametric magnetic resonance imaging (mpMRI) may be valuable. This study was performed to explore the value of the Vesical Imaging-Reporting and Data System (VI-RADS) and the volumetric apparent diffusion coefficient (ADC) histogram parameters in detecting T2 stage and below stage (≤T2 stage) from T3 stage and above stage (≥T3 stage) BCs. Methods: The study included 62 patients (mean age, males vs. females: 62.1±10.9 vs. 61.8±11.7 years) with BC pathologically confirmed by partial or radical cystectomy. All of the tumors were scored normatively by two radiologists using the VI-RADS scoring system by two radiologists. The volumetric ADC histogram of each lesion was obtained from the ADC maps. The Cochran-Armitage test was used to examine the relevance between VI-RADS scores and T stages. The Mann-Whitney U test was used to compare the histogram parameters between ≤T2 stage and ≥T3 stage BCs. A receiver operating characteristic (ROC) curve was used to assess the predictive power of each model. Results: The minimum ADC; mean ADC; median ADC; maximum ADC; and 10th, 25th, 75th, and 90th percentile ADC of ≤T2 stage BCs were significantly higher than those of ≥T3 stage BCs, while skewness and kurtosis had opposite results. VI-RADS achieved the highest area under the curve (AUC) of 0.834 among all parameters. The combination of VI-RADS, skewness and kurtosis yield a significantly higher AUC than VI-RADS alone (0.915 vs. 0.834, P=0.0478). Conclusions: VI-RADS and volume ADC histogram analysis can effectively discriminate between ≤T2 stage and ≥T3 stage BCs, and the volumetric ADC histogram can provide further information to supplement VI-RADS.

A scalable and anti-fouling silver-nickel/cellulose paper with synergy photothermal effect for efficient solar distillation.

Solar interfacial evaporation is one of the most efficient and environmentally-friendly clean freshwater production technologies. Plasma metal nanoparticles are excellent optical absorption materials, but their high cost and inherent resonance narrow bandwidth absorption limit their application. In this work, commercial cellulose papers are used as substrates to synthesize Ag-Ni/cellulose paper by the seed-mediated method. The Ag-Ni/cellulose paper exhibits high light absorption at the full wavelength (200-2500 nm) resulting from the synergistic effect of localized surface plasmon resonance (LSPR) of Ag NPs and the interband transitions (IBTs) of Ni. Under one-sun irradiation (1 kW m-2), the energy utilization efficiency of Ag-Ni/cellulose paper is as high as 93.8%, and the water evaporation rate is 1.87 kg m-2 h-1. Diffusion inhibition experiment results show that the Ag-Ni/cellulose paper exhibits excellent antibacterial performance, and the antibacterial performance is highly related with Ag NPs content. These provide new opportunities for commercial production of competitive cost, green, and portable solar evaporators for different application sceneries.

Advanced Stimuli-Responsive Structure Based on 4D Aerogel and Covalent Organic Frameworks Composite for Rapid Reduction in Tetracycline Pollution.

Intelligentization of materials and structures is an important trend. Herein, the stimuli-responsive 4D aerogel is used as a smart substrate for rapid reduction in tetracycline (TC) pollution, in which this smart stimuli-responsive substrate is designated as P4D. Its fourth dimension originates from stimuli-responsive characteristics with time evolution. Meanwhile, the covalent organic frameworks (COFs) composite is constructed by BiPO4 and triazine-based sp2 carbon-conjugated g-C18N3-COF (COF-1), which is another key aspect of COF-1/BiPO4@P4D for rapid photocatalytic degradation regarding TC pollution. This emerging smart structure of COFs@P4D can fix programmable temporary state and recover permanent state under thermal or water stimulus without any complicated equipment. Its performance can be tailored by structure, composition, and function. Compared with traditional powder-form photocatalysts, this stimuli-responsive structure provides attractive advantages, such as high permeable framework, self-adaptivity, flexibly customized functional groups, and fast reduction in TC pollution. The predictable development of COFs@P4D could draw much attention for various promising applications in pollution treatment and sensors.

Chiral molecule induced valley polarization enhancement of MoS2.

Monolayers of transition metal dichalcogenides (TMDCs) are atomically thin direct-bandgap semiconductors with potential applications in nanoelectronics, opto-electronics, and electrochemical sensing. Recent theoretical and experimental results have suggested that they are ideal systems for exploiting the valley degrees of freedom of Bloch electrons. Here, we report detailed studies of the opto-valleytronic properties of a chiral histidine molecule embedded in monolayer MoS2 single crystals grown via chemical vapor deposition. By irradiating MoS2 with circularly polarized light and measuring the resulting spatially resolved circularly polarized emission, we find the existence of a significantly increased circular polarization for D-histidine doped MoS2. The increased valley contrast is attributed to the selective enhancement of both the excitation and emission rates having one particular handedness of the circular polarization. These results provide a promising pathway to enhance the valley contrast for monolayer TMDCs at room temperature.

FGFR3 mutation characterization identifies prognostic and immune-related gene signatures in bladder cancer.

BACKGROUND: Immunotherapy and FGFR3-targeted therapy play an important role in the management of locally advanced and metastatic bladder cancer (BLCA). Previous studies indicated that FGFR3 mutation (mFGFR3) may be involved in the alterations of immune infiltration, which may affect the priority or combination of these two treatment regimes. However, the specific impact of mFGFR3 on the immunity and how FGFR3 regulates the immune response in BLCA to affect prognosis remain unclear. In this study, we aimed to elucidate the immune landscape associated with mFGFR3 status in BLCA, screen immune-related gene signatures with prognostic value, and construct and validate a prognostic model. METHODS: ESTIMATE and TIMER were used to assess the immune infiltration within tumors in the TCGA BLCA cohort based on transcriptome data. Further, the mFGFR3 status and mRNA expression profiles were analyzed to identify immune-related genes that were differentially expressed between patients with BLCA with wild-type FGFR3 or mFGFR3 in the TCGA training cohort. An FGFR3-related immune prognostic score (FIPS) model was established in the TCGA training cohort. Furthermore, we validated the prognostic value of FIPS with microarray data in the GEO database and tissue microarray from our center. Multiple fluorescence immunohistochemical analysis was performed to confirm the relationship between FIPS and immune infiltration. RESULTS: mFGFR3 resulted in differential immunity in BLCA. In total, 359 immune-related biological processes were enriched in the wild-type FGFR3 group, whereas none were enriched in the mFGFR3 group. FIPS could effectively distinguish high-risk patients with poor prognosis from low-risk patients. The high-risk group was characterized by a higher abundance of neutrophils; macrophages; and follicular helper, CD4, and CD8 T-cells than the low-risk group. In addition, the high-risk group exhibited higher expression of PD-L1, PD-1, CTLA-4, LAG-3, and TIM-3 than the low-risk group, indicating an immune-infiltrated but functionally suppressed immune microenvironment. Furthermore, patients in the high-risk group exhibited a lower mutation rate of FGFR3 than those in the low-risk group. CONCLUSIONS: FIPS effectively predicted survival in BLCA. Patients with different FIPS exhibited diverse immune infiltration and mFGFR3 status. FIPS might be a promising tool for selecting targeted therapy and immunotherapy for patients with BLCA.

A chromosome-level genome assembly of Hong Kong catfish (Clarias fuscus) uncovers a sex-determining region.

BACKGROUND: Hong Kong catfish (Clarias fuscus) is an ecologically and economically important species that is widely distributed in freshwater regions of southern China. Hong Kong catfish has significant sexual growth dimorphism. The genome assembly of the Hong Kong catfish would facilitate study of the sex determination and evolution mechanism of the species. RESULTS: The first high-quality chromosome-level genome of the Hong Kong catfish was constructed. The total genome was 933.4 Mb, with 416 contigs and a contig N50 length of 8.52 Mb. Using high-throughput chromosome conformation capture (Hi-C) data, the genome assembly was divided into 28 chromosomes with a scaffold N50 length of 36.68 Mb. A total of 23,345 protein-coding genes were predicted in the genome, and 94.28% of the genes were functionally annotated in public databases. Phylogenetic analysis indicated that C. fuscus and Clarias magur diverged approximately 63.7 million years ago. The comparative genome results showed that a total of 60 unique, 353 expanded and 851 contracted gene families were identified in Hong Kong catfish. A sex-linked quantitative trait locus identified in a previous study was located in a sex-determining region of 30.26 Mb (0.02 to 30.28 Mb) on chromosome 13 (Chr13), the predicted Y chromosome. This QTL region contained 785 genes, of which 18 were identified as sex-related genes. CONCLUSIONS: This study is the first to report the chromosome-level genome assembly of Hong Kong catfish. The study provides an excellent genetic resource that will facilitate future studies of sex determination mechanisms and evolution in fish.

Histopathological bladder cancer gene mutation prediction with hierarchical deep multiple-instance learning.

Gene mutation detection is usually carried out by molecular biological methods, which is expensive and has a long-time cycle. In contrast, pathological images are ubiquitous. If clinically significant gene mutations can be predicted only through pathological images, it will greatly promote the widespread use of gene mutation detection in clinical practice. However, current gene mutation prediction methods based on pathological images are ineffective because of the inability to identify mutated regions in gigapixel Whole Slide Image (WSI). To address this challenge, hereby we propose a carefully designed framework for WSI-based gene mutation prediction, which consists of three parts. (i) The first part of cancerous area segmentation, based on supervised learning, quickly filters out a large number of non-mutated regions; (ii) the second part of cancerous patch clustering, based on the representations derived from contrastive learning, ensures the comprehensiveness of patch selection; and (iii) the third part of mutation classification, based on the proposed hierarchical deep multi-instance learning method (HDMIL), ensures that sufficient patches are considered and inaccurate selections are ignored. In addition, benefiting from a two-stage attention mechanism in HDMIL, the patches that are highly correlated with gene mutations can be identified. This interpretability can help a pathologist to analyze the correlation between gene mutation and histopathological morphology. Experimental results demonstrate that the proposed gene mutation prediction framework significantly outperforms the state-of-the-art methods. In the TCGA bladder cancer dataset, five clinically relevant gene mutations are well predicted.

Hierarchical structure design of sea urchin Shell-Based evaporator for efficient omnidirectional Solar-Driven steam generation.

Solar-driven steam generation (SSG) is regarded as a feasible solution to the problem of fresh water scarcity. Although several attempts have been devoted to increase the efficiency of solar-to-steam conversion, it remains difficult to fabricate cost-effective, steady, and multi-angle sunlight-absorbing evaporators from readily available biomass materials. Herein, a novel hierarchical structured SSG evaporator (PDA@Shell-NaClO) is developed through a simple, low-cost, and scalable etching treatment on discarded sea urchin (SU) shells. Attributing to the dedicatedly designed microneedles array structure and porous skeleton structure of the SU shell, this PDA@Shell-NaClO evaporator shows an outstanding average light absorption performance (>90%) in a broad range of angles from 0° to 60° and exceedingly high evaporation rate of 2.81 kg m-2 h-1 under one sun condition. Furthermore, the prepared evaporator also maintains an overall stable evaporation performance and exhibits an excellent durability for a long time of up to two weeks in actual seawater. This full-ocean biomass-based SSG evaporator with plentiful raw material availability offers innovative opportunities for large-scale fresh water production.

Value of contrast-enhanced magnetic resonance imaging-T2WI-based radiomic features in distinguishing lung adenocarcinoma from lung squamous cell carcinoma with solid components >8 mm.

Background: Radiomics is one of the research frontiers in the field of imaging and has excellent diagnostic performance. However, there is a lack of magnetic resonance imaging (MRI)-based omics studies on identifying pathological subtypes of lung cancer. Here we explored the value of the contrast-enhanced MRI-T2-weighted imaging (T2WI)-based radiomic analysis in distinguishing adenocarcinoma (Ade) from squamous cell carcinoma (Squ) with solid components >8 mm. Methods: A retrospective analysis was performed of a total of 71 lung cancer patients who undergoing contrast-enhanced MRI and computed tomography (CT) before treatment, and the nodules had solid components ≥8 mm in our center from January 2020 to September 2021. All enrolled patients were divided into Squ and Ade groups according to the pathological results. In addition, the two groups were randomly divided into training set and validation set in a ratio of about 7:3. Radiomics software was used to extract the relevant radiomic features. The least absolute shrinkage and selection operator (Lasso) was used to screen radiomic features that were most relevant to lung cancer subtypes, thus calculating the radiomic scores (Rad-score) and constructing the radiomic models. Multivariate logistic regression was used to combine relevant clinical features with Rad-score to form combined model nomograms. The receiver operating characteristic (ROC) curves. the area under the ROC curve (AUC), the decision curve analysis (DCA) and the DeLong's test were used to evaluate the clinical application potentials. Results: The sensitivity and specificity of the clinical model based on smoking was 75.0% and 93.8%. The AUC of the constructed magnetic resonance (MR)-Rad model for differentiating the pathological subtypes of lung cancer was 0.8651 in the validation sets. The AUC of the CT-Rad model in the validation set were 0.9286. The combined model constructed by combining clinical features and Rad-score had AUC of 0.8016, for identifying the 2 pathological subtypes of lung cancer in the validation set. There was no significant difference in diagnostic performance between MR-Rad model and CT-Rad model (P>0.05). Conclusions: The MR-Rad model has a diagnostic performance similar to that of CT-Rad model, while the diagnostic performance of the combined mode was better than the single MR model.

Feasibility analysis of coexistence between plantation and tower concentrating solar system.

There are large-scale thermal utilization needs in rural and urban fringes in China that can provide many employment opportunities. However, due to the limited use of small and medium-sized coal-fired boilers, thermal energy is actually in short supply. If embedding these spaces including plantations with solar heliostat fields, a large number of nodes for cheap thermal energy supply can be obtained through solar energy, which can create more small-scale industrial and commercial employment opportunities near user side. However, to ensure the crop harvest, plantations are often prohibited from being used for other purposes. In order to verify the idea of coexistence between tower concentrating solar system with sparse heliostat field and plantation, the clean-sky model was used to analyze the shading rate of the heliostat to the ground in each month and the proportion of the area with a relative sunshine duration of less than 80% for the heliostat fields at low, middle, and high latitude areas, and further gave the correction of the above analysis results using typical meteorological year conditions. The results show that heliostats in mid latitude area have obvious adverse effects on overwintering crops. In high latitude area, although the heliostats are more severely blocked in the cold season, there is no planting activity in this season, so the impact on planting can be ignored. The shade ratio of the heliostats to the ground in low, middle and high latitude regions is tolerable in the months suitable for planting, and shade-tolerant crops can also be interplanted in the shaded area to enrich the variety structure. Therefore, by embedding the tower concentrating solar system with a sparse heliostat field, the plantation can meet the two functions of planting and thermal energy supply at the same time to further increase its income.

Synthesis of Phase Junction Cadmium Sulfide Photocatalyst under Sulfur-Rich Solution System for Efficient Photocatalytic Hydrogen Evolution.

Photocatalyst with excellent semiconductor properties is the key point to realize the efficient photocatalytic hydrogen evolution (PHE). As a representative binary metal sulfide (BMS) semiconductor, cadmium sulfide (CdS) possesses suitable bandgap of 2.4 eV and negative conduction band potential, which has a great potential to realize efficient visible-light PHE performance. In this work, CdS with unique cubic/hexagonal phase junction is facilely synthesized through a sulfur-rich butyldithiocarbamate acid (BDCA) solution process. The results illustrate that the phase junction can efficiently enhance the separation and transfer of photogenerated electron-hole pairs, resulting in an excellent PHE performance. In addition, the sulfur-rich property of BDCA solution leads to the absence of additional sulfur sources during the synthesis of CdS photocatalyst, which greatly simplifies the fabrication process. The optimal PHE rate of the BDCA-synthesized phase junction CdS photocatalyst is 7.294 mmol g-1  h-1 and exhibits a favorable photostability. Moreover, density function theory calculations indicated that the apparent redistribution of charge density in the cubic/hexagonal phase junction regions gives a suitable hydrogen adsorption capacity, which is responsible for the enhanced PHE activity.

Inherited mutations in Chinese patients with upper tract urothelial carcinoma.

Upper tract urothelial carcinoma (UTUC) accounts for 10% of urothelial carcinomas (UCs) and has a substantial hereditary component. However, the majority of our knowledge of germline spectrum comes from bladder cancer (BCa) data in White populations. Here, we sequence 309 Chinese UTUC cases and identify 71 germline pathogenic/likely pathogenic (P/LP) mutations in 62 patients (20.1%). Compared with White cases, we observe disparities and similarities in inherited mutational profiles. Association analysis reveals that germline P/LP mutations in MSH2, BRCA2, BRCA1, and BRIP1 significantly increase UTUC risk in Chinese populations. Furthermore, germline P/LP mutation in homologous recombination genes indicates poor prognosis for non-metastatic UTUC. Finally, we perform paired sequencing and observe significant correlations between germline mutation patterns and tumor subtypes. This study highlights the importance of genetic testing in patients with UTUC and calls for germline data from various ethnicities to better understand this disease.

Overall Carbon-neutral Electrochemical Reduction of CO2 in Molten Salts using a Liquid Metal Sn Cathode.

An overall carbon-neutral CO2 electroreduction requires enhanced conversion efficiency and intensified functionality of CO2 -derived products to balance the carbon footprint from CO2 electroreduction against fixed CO2 . A liquid Sn cathode is herein introduced into electrochemical reduction of CO2 in molten salts to fabricate core-shell Sn-C spheres (Sn@C). An in situ generated Li2 SnO3 /C directs a self-template formation of Sn@C. Benefitting from the accelerated reaction kinetics from the liquid Sn cathode and the core-shell structure of Sn@C, a CO2 -fixation current efficiency higher than 84 % and a high reversible lithium-storage capacity of Sn@C are achieved. The versatility of this strategy is demonstrated by other low melting point metals, such as Zn and Bi. This process integrates energy-efficient CO2 conversion and template-free fabrication of value-added metal-carbon, achieving an overall carbon-neutral electrochemical reduction of CO2 .

Clinicopathological characteristics and loss of mismatch repair protein expression in Chinese upper tract urothelial carcinomas.

Expression of DNA mismatch repair (MMR) protein (MLH1, PMS2, MSH2, and MSH6) in upper tract urothelial carcinoma (UTUC) has been explored in Western cohorts, but it is rarely reported in Eastern cohorts. We aimed to assess the loss of MMR protein expression among Chinese UTUC patients and study its clinicopathological implications. We enrolled 175 UTUC patients at our center and tested the expression of MMR proteins by immunohistochemistry. Then, we explored these patients' clinicopathological characteristics. We found loss of MMR proteins in 19 (10.9%) of 175 patients in our cohort (6 MSH2 and MSH6, 2 MSH6 alone, 6 MSH2 alone, 3 MLH1 and PMS2, and 2 PMS2 alone). Loss of MMR proteins was not a significant prognostic factor of relapse-free survival for these patients. In addition, patients with lower T stage or with bladder cancer history were more likely to have loss of MMR protein expression. At last, two metastatic patients (MSH2 and MSH6 loss; MSH2 loss) with loss of MMR protein experienced tumor recession after several cycles of anti-PD-1 immunotherapy. In conclusion, this is the largest Chinese UTUC cohort study to date that explores the loss of MMR protein expression. The rate of MMR loss observed was comparable to that in the Western UTUC cohort, supporting universal UTUC screening in China. Furthermore, a subset of advanced UTUCs with MMR protein loss are probably immunogenic, for whom single or combined immunotherapy may be potential therapeutic options in the future.

Studying Performance and Kinetic Differences between Various Anode Electrodes in Proton Exchange Membrane Water Electrolysis Cell.

The electrode, as one of the most critical components in a proton exchange membrane water electrolysis (PEMWE) cell for hydrogen production, has a significant impact on cell performance. Electrodes that are fabricated via various techniques may exhibit different morphologies or properties, which might change the kinetics and resistances of the PEMWE. In this study, we have successfully fabricated several electrodes by different techniques, and the effects of electrode coating methods (ultrasonic spray, blade coating, and rod coating), hot press, and decal transfer processes are comprehensively investigated. The performance differences between various electrodes are due to kinetic or high frequency resistance changes, while the influences are not significant, with the biggest deviation of about 26 mV at 2.0 A cm-2. In addition, the effects of catalyst ink compositions, including ionomer to catalyst ratio (0.1 to 0.3), water to alcohol ratio (1:1 to 3:1), and catalyst weight percentage (10% to 30%), are also studied, and the electrodes' performance variations are less than 10 mV at 2.0 A cm-2. The results show that the PEMWE electrode has superior compatibility and redundancy, which demonstrates the high flexibility of the electrode and its applicability for large-scale manufacturing.

The Impact of Improved Oral Care Methods on the Oral Health of Patients Undergoing Transoral Mechanical Ventilation.

Objective: To explore the effects of improved oral care on the number of oropharyngeal bacteria and the incidence of ventilator-associated pneumonia in patients undergoing mechanical ventilation through oral endotracheal intubation by improving conventional oral care methods and operating procedures and to evaluate the quality of improved oral care and effect. Methods: A total of 100 cases of mechanically ventilated patients with oral endotracheal intubation who met the inclusion criteria were randomly divided into the observation group and control group with 50 cases each. The control group took routine oral care, that is, scrubbing 3 times per day, and the oral care solution was selected as physiological brine. The observation group improved the conventional oral care method, namely, oral scrubbing before intubation, brushing and washing after intubation, 3 times per day, and 0.1% povidone-iodine in oral care solution. Analysis and comparison of the oral bacterial flora, oral cleanliness, and incidence of ventilator-associated pneumonia, mechanical ventilation time, ICU hospitalization time, and mortality rate of the two groups of patients were analyzed and compared. The relevant data were collected and processed for statistical processing. Results: The oral bacterial flora of the two groups of patients before oral care after mechanical ventilation after oral tracheal intubation was compared, and there was no significant statistical difference (P > 0.05). After nursing, the oral bacterial flora of the observation group at 8 h, 16 h, and 24 h after intubation was significantly lower than that of the control group. Statistics showed that the difference was statistically significant (P < 0.05). After nursing, the number of patients with oral cleanliness in the observation group was significantly higher than that of the control group, while the incidence of ventilator-associated pneumonia in the observation group was 8% significantly lower than that of the control group 14%. Statistics show that this difference is statistically significant (P < 0.05). After nursing, the observation group's oral cleanliness score, mechanical ventilation time, ICU hospitalization time, and GCS score were better than those of the control group. Statistics showed that the difference was statistically significant (P < 0.05). The mortality of the observation group was significantly lower than that of the control group, which was not statistically significant (P > 0.05). Conclusion: Oral care can effectively reduce the number of oropharyngeal bacteria in patients who are mechanically ventilated through orotracheal intubation and significantly reduce the incidence of ventilator-associated pneumonia.