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The aim of this study was to evaluate the effects of continuous application of rice straw and biochar for 10 years on soil humus composition and structure in paddy soil. A 10-year field experiment was conducted in a paddy field and included three treatments: rice straw biochar (SC); rice straw (RS), no biochar or rice straw. The elemental analyser, Fourier transform infrared (FT-IR) spectrum, and three-dimensional excitation-emission matrix (3D EEM) fluorescence spectroscopy with fluorescence regional integration (FRI) analysis were used to study the soil humus composition and structure under different treatments. The results verified that the incorporation of rice straw and biochar significantly improved soil pH values and the soil organic carbon contents compared with the control. Rice straw significantly increased the contents of extractable humus, humic acid (HA) and fulvic acid in soil, while biochar only significantly affected HA and humic degree values. The molecular structure of HA affected by biochar is characterised by high humification and aromaticity, but rice straw increased the aliphaticity of the HA structure, as presented by elemental composition. Moreover, 3D EEM spectroscopy combined with FRI analysis showed that RS treatment formed soil humus had more aliphatic compounds, while SC treatment increased the aromatic components of humus. These results suggest that rice straw promotes the renewal of humus, and biochar enhances the humification degree of humus and the aromaticity of HA.

Abstract Background In the context of deeper integration of the internet and healthcare services, eHealth literacy levels have become an important predictor of public health outcomes and health-promoting behaviors. However, there is a lack of comprehensive understanding of eHealth literacy levels among older adults. Objective To systematically assess the level of eHealth literacy among older adults. Methods We conducted searches in MEDLINE, Embase, Web of Science, CINAHL, PsycINFO, China National Knowledge Infrastructure Database (CNKI), Wanfang Database, Weipu Database (VIP), and Chinese Biomedical Database (Sinomed) to collect survey studies on the eHealth literacy levels of the older adults, with a search timeframe from the establishment of the database to May 2024. The quality of the included literature was assessed using the Agency for Healthcare Research and Quality (AHRQ) and the Newcastle-Ottawa Scale (NOS). Additionally, subgroup analysis and meta-regression were conducted to detect sources of heterogeneity. Funnel plots and Egger’s test were used to assess publication bias. Results A total of 48 relevant studies were included, including 45 cross-sectional, 2 cohort studies and 1 longitudinal study, comprising 33,919 older adults. The quality of the studies was all above moderate, with 10 high-quality publications. Meta-integration results showed that the eHealth literacy score of older adults was 21.45 (95% CI:19.81–23.08). Subgroup analysis showed that among the elderly population, females had lower eHealth literacy at 19.13 (95% CI:15.83–22.42), those aged 80 years and older had lower eHealth literacy at 16.55 (95% CI:11.73–21.38), and elderly individuals without a spouse and living alone had even lower eHealth literacy at 18.88 (95% CI:15.71–22.04) and 16.03 (95% CI:16.51–21.79). Based on region, eHealth literacy was lower among older adults in developing countries at 20.71 (95% CI:18.95–22.48). Meta-regression results indicate that sample size and region can significantly impact heterogeneity. Conclusion Our results found that the average eHealth literacy score of the elderly was 21.45, which was much lower than the passing level (≥ 32), suggesting that more attention should be paid to the eHealth literacy aspect of the elderly. Meanwhile, due to the limitation of the literature sources, the global representativeness of the results of this study still needs to be supported by more research data from other countries.

Abstract Skin cutaneous melanoma (SKCM) is a highly malignant form of skin cancer, known for its unfavorable prognosis and elevated mortality rate. RARRES1, a gene responsive to retinoic acid receptors, displays varied functions in various cancer types. However, the specific role and underlying mechanisms of RARRES1 in SKCM are still unclear. GSE15605 was utilized to analyze the expression of RARRES1 in SKCM. Subsequently, the TCGA and GEO databases were employed to investigate the relationships between RARRES1 and clinicopathological parameters, as well as the prognostic implications and diagnostic efficacy of RARRES1 in SKCM. GO, KEGG, and GSEA analyses were conducted to explore the potential functions of RARRES1. Furthermore, the associations between RARRES1 and immune infiltration were examined. Genomic alterations and promoter methylation levels of RARRES1 in SKCM were assessed using cBioPortal, UALCAN, and the GEO database. Finally, RARRES1 expression in SKCM was validated through immunohistochemistry, and its functional role in SKCM progression was elucidated via in vivo and in vitro experiments. We found that RARRES1 was downregulated in SKCM compared with normal tissues, and this low expression was associated with worse clinicopathological features and poor prognosis of SKCM. The diagnostic efficacy of RARRES1, as determined by ROC analysis, was 0.732. Through GO, KEGG, and GSEA enrichment analysis, we identified 30 correlated genes and pathways that were mainly enriched in the tumor immune microenvironment, proliferation, apoptosis, and autophagy. Additionally, RARRES1 expression was found to be positively related to the infiltration of various immune cells in SKCM, particularly macrophages and T helper cells, among others. Analysis of genomic alterations and promoter methylation revealed that shallow deletion and hypermethylation of the RARRES1 promoter could lead to reduced RARRES1 expression. IHC validation confirmed the downregulation of RARRES1 in SKCM. Moreover, overexpression of RARRES1 inhibited the proliferation and migration of A375 cells, promoted apoptosis, and inhibited autophagic flux. In the mouse xenograft model, RARRES1 overexpression also suppressed SKCM tumor growth. Collectively, these findings suggest that RARRES1 may function as a suppressor and could potentially serve as a prognostic biomarker and therapeutic target for SKCM.

To improve the performance of hydrocyclones for in-situ natural gas hydrate recovery and desanding, this study analyzed the hydrocyclone’s sensitivity factors, optimized the structural parameters, and investigated the adaptability to the reservoir and operating parameters through numerical simulations and experiments. Results showed that the optimal structural parameters were spiral pitch of 24 mm, vortex finder diameter of 36 mm, spigot diameter of 26 mm, number of spirals equals 5, and cone angle of 6°. Under the optimal parameter configuration, the efficiency of the hydrocyclone is exceeded 90%, and the pressure drop was within 0.5 MPa. When the inlet natural gas hydrate volume concentration, or the inlet sand volume concentration are increased, the separation efficiency and pressure drop changed only slightly. The natural gas hydrate hydrocyclone showed good adaptability to the reservoir and operating parameters. These findings provide theoretical guidance for the design and construction of natural gas hydrate in-situ separators.

The paper proposes and verifies a small-angle measurement method based on the defect spot mode of the position-sensitive detector (PSD). With the output characteristics of the PSD in the defect spot mode and the size transformation properties of a focused beam, the measurement sensitivity can be significantly improved. Calibration experiments with the piezoelectric transducer (PZT) indicate that compared with the current PSD-based autocollimation method, the proposed method can improve the sensitivity of small-angle measurement by 57 times, and the measurement sensitivity of the proposed method can be further improved by optimizing the system parameters, while the proposed method has the advantages of a simple system and high real-time performance. Therefore, the proposed method is expected to be used in high-precision motion error detection, as well as in shape and position measurement.

A low-cost metal-organic framework suitable for high-efficiency production is synthesized by a solvothermal method using a transition element Zn and 4-hydroxybenzoic acid (HBA). These hollow Zn-HBA nanospheres are added to epoxy resin-based coating (E 51-LP 3) to form a flame-retardant and thermal insulation coating. Data obtained from cone calorimetric test demonstrates that the addition of Zn-HBA nanospheres effectively inhibits the combustion and smoke release of the coating. At Zn-HBA content of 50.0 vol%, the limiting oxygen index increases by 46% (from 21.5% to 31.5%) and UL 94 rating reaches V-0. Moreover, the thermal insulation performance of E 51-LP 3 containing 50 vol% Zn-HBA as flame-retardant is also significantly improved. This work demonstrates that these low-cost hollow Zn-HBA nanospheres, suitable for high-efficiency production, can be used as an additive to produce nanocoatings with both excellent flame-retardant and thermal insulation properties, while providing a solution for reducing the cost of multifunctional coatings.

Abstract Background The present study intended to establish a predictive nomogram for early relapse (ER) ( UNL, and response less than very good partial response (VGPR) after ASCT. The calibration curve showed good fitness between the nomogram predictions and the actual observations and the nomogram was further validated by a clinical decision curve. The nomogram's C‐index achieved 0.75 (95% CI, 0.70–0.80), which was higher than that of the Revised International Staging System (R‐ISS) (0.62), ISS (0.59), and Durie–Salmon (DS) staging system (0.52). The discrimination ability of the nomogram in the validation cohort was superior to that of the other staging systems (C‐index: 0.73 vs. R‐ISS (0.54), ISS (0.55), and DS staging system (0.53)). DCA showed the prediction nomogram adds much more clinical utility. Different scores of the nomogram draw a distinction of OS. Conclusion The present nomogram could serve as a feasible and accurate prediction of ER in novel drug induction transplantation‐eligible MM patients, which could help modify the post‐ASCT strategy for patients at high risk of ER.

Abstract Oil-impregnated porous polyimide (iPPI) materials are usually used as retainer for bearings. In these bearings, balls and rings, balls and retainers are two different kinds of contact. In this paper, the friction and wear properties of iPPI were investigated using steel (disc)—steel (ball)—iPPI (pin) double-contact friction test rig for simulating the actual contact in bearings. The results show that compared with that of iPPI—steel single contact, the friction coefficient of iPPI—steel in double contacts is lower and decreases with the amount of additional oil. The surface of iPPI in single contact suffers more wear compared with that in double contacts. Different from single contact, the worn surfaces of iPPI in double contacts are blackened. The Raman spectra of worn surfaces of balls and discs indicate that α-Fe2O3 and Fe3O4 were formed during rubbing of the double contacts. Many nanoscale iron oxide particles are found on the worn surfaces of iPPI in double contacts; on the contrary, few particles could be found on the surface in single contact. In double-contact friction, the nanoscale wear debris penetrates inside the iPPI material through the process of extruding and recycling of oil, which is the mechanism of the blackening of the iPPI worn surfaces. The studies show that the double-contact friction method is a new and effective method to study the friction in bearings, especially for those with polymer retainer.

Equipment failure risk identification and risk assessment are essential part of offshore platform equipment integrity management. Realizing the risk identification and quantitative assessment of offshore platform equipment and failure modes will help to formulate more reasonable risk management measures. However, the previous methods are not enough to support precise risk assessment of offshore platform equipment. Therefore, this paper proposes a new quantitative risk assessment method based on fuzzy set theory, gray correlation analysis and fuzzy Borda method. This paper creatively proposed the approach, which integrates the solid expressive ability of the fuzzy set theory to vagueness and uncertainty information, the strong point of GRA method in studying the dependence of failure modes, and the advantage of FBM for aggregating experts’ diversity evaluations. Based on the above integrated approach, the proposed risk assessment model can favorably capture and aggregate diversity evaluations of FMECA team members. In addition, the effectiveness of this method is verified by the risk assessment of offshore platform equipment. The new method solves the problem existing in the quantitative risk assessment of multiple risks and multiple FMECA reports. This comprehensive quantitative risk assessment method can screen out high-risk failure modes and essential components in a system, and provide a reference for maintenance decision-making of complex industrial systems. This paper is conducive to promote the application of PHM, RCM and AIM in high-risk industries such as oil and gas production.

Because of its significant advantage of fast postoperative recovery, natural orifice specimen extraction surgery (NOSES) has attracted increasing attention worldwide. However, the NOSES in gastric cancer (GC) treatment still needs more clinical practice, especially for the rare anatomical anomaly. Situs inversus totalis (SIT) is a rare autosomal recessive anatomical anomaly with an incidence ranging between 1/8,000 and 1/25,000 births. We present a video of transvaginal specimen extraction following totally laparoscopic D2 distal gastrectomy performed in a 59-year-old woman known to have SIT. Preoperative investigations revealed that the patient had early GC at the antrum. A gastroscopy report from the local hospital showed signet-ring cell carcinoma. The preoperative computed tomography scan revealed irregular thickening of the gastric wall at the junction of the greater curvature and antrum without metastasis to the lymph nodes. In total, laparoscopic D2 distal gastrectomy was performed with transvaginal specimen extraction. Billroth II with Braun anastomosis was performed for reconstruction. The length of the operation was 240 min without intraoperative complications and with minimal blood loss of 50 ml. The patient was uneventfully discharged on postoperative Day 7. The final pathology confirmed signet-ring cell carcinoma confined to the mucosal muscle without metastasis in 16 lymph nodes. Transvaginal specimen extraction following totally laparoscopic D2 distal gastrectomy can be safely performed in patients with SIT and has similar surgical outcomes to usual laparoscopic gastrectomy.

Abstract Apoptosis is a critical event in the pathogenesis of lung ischemia/reperfusion (I/R) injury. Sirtuin 3 (SIRT3), an important deacetylase predominantly localized in mitochondria, regulates diverse physiological processes, including apoptosis. However, the detailed mechanisms by which SIRT3 regulates lung I/R injury remain unclear. Many polyphenols strongly regulate the sirtuin family. In this study, we found that a polyphenol compound, procyanidin B2 (PCB2), activated SIRT3 in mouse lungs. Due to this effect, PCB2 administration attenuated histological lesions, relieved pulmonary dysfunction, and improved the survival rate of the murine model of lung I/R injury. Additionally, this treatment inhibited hypoxia/reoxygenation (H/R)-induced A549 cell apoptosis and rescued Bcl-2 expression. Using Sirt3-knockout mice and specific SIRT3 knockdown in vitro, we further found that SIRT3 strongly protects against lung I/R injury. Sirt3 deficiency or enzymatic inactivation substantially aggravated lung I/R-induced pulmonary lesions, promoted apoptosis, and abolished PCB2-mediated protection. Mitochondrial pyruvate kinase M2 (PKM2) inhibits apoptosis by stabilizing Bcl-2. Here, we found that PKM2 accumulates and is hyperacetylated in mitochondria upon lung I/R injury. By screening the potential sites of PKM2 acetylation, we found that SIRT3 deacetylates the K433 residue of PKM2 in A549 cells. Transfection with a deacetylated mimic plasmid of PKM2 noticeably reduced apoptosis, while acetylated mimic transfection abolished the protective effect of PKM2. Furthermore, PKM2 knockdown or inhibition in vivo significantly abrogated the antiapoptotic effects of SIRT3 upregulation. Collectively, this study provides the first evidence that the SIRT3/PKM2 pathway is a protective target for the suppression of apoptosis in lung I/R injury. Moreover, this study identifies K433 deacetylation of PKM2 as a novel modification that regulates its anti-apoptotic activity. In addition, PCB2-mediated modulation of the SIRT3/PKM2 pathway may significantly protect against lung I/R injury, suggesting a novel prophylactic strategy for lung I/R injury.

Abstract A metal–organic framework (MOF) formed between Zn and p‐hydroxybenzoic acid (PHBA) is synthesized using a solvothermal method. These Zn‐PHBA nanorods, which are inexpensive and suitable for mass production, are added as a flame‐retardant into vinyl resin (430 LV, a material used in marine composites). Data from cone calorimetric test demonstrates that adding the Zn‐PHBA nanorods to 430 LV significantly improves flame retardation and smoke suppression. At a high Zn‐PHBA content of 10.0 wt%, the limiting oxygen index of 430 LV increases from 19.5% to 28.5%, and the material reaches the V‐0 rating in vertical burning tests (UL‐94). Moreover, the tensile and impact strengths of 430 LV containing 10 wt% Zn‐PHBA as flame‐retardant do not deteriorate and are even slightly improved. This work demonstrates that this MOF synthesized by a simple and efficient method may be used to produce nanocomposites with excellent flame retardation and mechanical properties, while keeping the material cost sufficiently low for marine applications.

Abstract Thermal decomposition in solution is the most effective approach for achieving highly monodisperse iron oxide nanoparticles (IONPs). However, a simple, economical, and environment‐friendly iron precursor with high iron content remains in great demand. Although siderite (FeCO3) has been reported to produce iron oxide particles via calcination, it is difficult to control the shapes of the obtained particles compared to those obtained by solution methods. Herein, FeCO3 was employed as a precursor in solution thermal decomposition to prepare monodisperse IONPs and investigated the influence of reaction conditions on the particle size, including the concentration of oleic acid, concentration of the precursor, and the reaction temperature. The seed‐mediated growth method with FeCO3 as a precursor was also studied to extend the scope of particle size. The experimental results demonstrate that high‐quality IONPs can be synthesized in solution via FeCO3 thermal decomposition. The particle diameter was tuned between 3 and 20 nm by varying the reaction conditions, and by seed‐mediated growth. FeCO3 is thus a readily available, economical, environment‐friendly precursor with high iron content, which is a novel candidate for the synthesis of IONPs.

Aiming at the operation conflict problem of multi-objective, multi-path and multi-vehicle relay during mine locomotive operation under complex geological conditions, a mine operation of locomotive modeling method based on an object-oriented stratified timed Petri net is proposed. In order to load and transport materials as object oriented, which are combined with the mine operation of locomotive rules and time constraints, stratified modeling of an underground roadway route is carried out. In addition, given token time parameters to describe the dynamic behavior of the locomotive, through the model to analyze the operation of a mine transport locomotive, the correlation matrix and accessibility tree analysis are used to study the conflict. Taking the actual operation of a locomotive in a complex mine in Guizhou as an example, the operation of locomotive behavior model was established to detect the interval and time of operation conflicts. The experimental results show that the proposed operation of locomotive modeling and conflict analysis method are effective and feasible, and have important application value to the safe operation of a mine production system.

Abstract The purpose of the study was to investigate the application of virtual monoenergetic images (VMIs) in reducing metal artifacts in rabbit VX2 liver cancer models treated with microwave ablation (MWA) therapy. A total of 31 VX2 liver cancer models that accepted CT-guided percutaneous microwave ablation were analyzed. Conventional images (CIs) with the most severe metallic artifacts and their corresponding energy levels from 40 to 200 keV with 10 keV increment of VMIs were reconstructed for further analysis. Objective image analysis was assessed by recording the attenuation (HU) and standard deviation of the most severe hyper/hypodense artifacts as well as artifact-impaired liver parenchyma tissue. Two radiologists visually evaluated the extent of artifact reduction, assessed data obtained by a diagnostic evaluation of liver tissues, and appraised the appearance of new artifacts according to the grade score. Statistical analysis was performed to compare the difference between CIs and each energy level of VMIs. For subjective assessment, reductions in hyperdense and hypodense artifacts were observed at 170–200 keV and 160–200 keV, respectively. The outcomes of the diagnostic evaluation of adjacent liver tissue were statistically higher at 140–200 keV for VMIs than for CIs. In terms of objective evaluation results, VMIs at 90–200 keV reduced the corrected attenuation of hyperdense and of artifact-impaired liver parenchyma compared with CIs (P

Abstract Background Autologous stem cell transplantation (ASCT) has been recommended as a standard approach for young multiple myeloma (MM) patients for decades, even in the era of novel agents. Gain of chromosome 1q21 is a common cytogenetic abnormality in MM, while its clinical prognostic value is still controversial. Methods In this multicenter study, we retrospectively analyzed 1q21 gain in 446 newly diagnosed MM patients who received at least one ASCT from three large myeloma centers in China. Results Of the all 446 patients, 1q21 gain was an adverse predictor of progression‐free survival (PFS) (34 vs 56 months, P = .005) and overall survival (OS) (69 vs 100 months, P = .002). Gain of 1q21 was more likely to coexist with t(4;14), t(14;16), and del(13q). Nevertheless, isolated 1q21 gain still exhibited unfavorable effects on PFS (35 vs 66 months, P = .045) and OS (61 vs 100 months, P = .026). The coexistence of 1q21 gain and high‐risk cytogenetics (HRCs) [del(17p), t(4;14),and/or t(14;16)] showed poor prognosis on both PFS and OS, while no additional adverse effect could be identified when compared with HRCs alone. Moreover, when coexisting with t(11;14), patients with 1q21 gain showed a comparable survival to those without 1q21 gain. For patients treated with novel induction regimens followed by ASCT, 1q21 gain also conferred an inferior prognosis. Multivariate analysis further confirmed 1q21 gain could independently predict shorter PFS and OS. Conclusion In conclusion, 1q21 gain is an adverse prognostic factor for MM patients received ASCT.

Abstract Jet breaking using a high‐pressure nozzle is one solution for breaking natural gas hydrate (NGH) formations, creating a larger breaking volume and fluidizing broken solid fragments. Based on the analysis of various jet breaking mechanisms for the variation of the flow velocity of the internal and outlet sections of different nozzles, a straight‐swirling mixed nozzle (SSMN) was designed. We obtained different jet breaking effects for a single nozzle, including the influences of the working pressure and target distance on the hole shape, as well as working pressure on hole parameters and target distance on hole parameters. In addition, we analyzed the influences of the nozzle number, type of NGH rock, and construction parameters on the rock‐breaking efficiency and selected the best combination mode of multiple nozzles. The research results of the rock‐breaking mechanism and efficiency of the SSMN promotes the development of commercial mining technology for nondiagenetic NGH in deep‐sea shallow areas.

The motion of the floating platform is one of the important factors influencing the safety of testing string. The allowable motion limits of various floating drilling platforms are discussed and their calculation formulas are presented, based on which the nonlinear dynamic response characteristics of the testing tube are investigated through ABAQUS software. Results show that an excessive offset of floating platform will cause many problems to testing tube, such as operation difficulty in rising and landing pipe string, disconnection difficulty of testing tree in case of emergency. Under heave motion and slow drift motion condition, the maximum Mises stress appears in the part closed to the upper end. The heave and horizontal motions of the platform have a superposition influence on the axial force of the pipe. So, a more precise dynamic theoretical model should be developed to study the longitudinal-transverse coupled vibration of testing string in the future.

Follicular thyroid carcinoma (FTC) is a common endocrine malignancy with highly aggressive features. In this study, next-generation sequencing technology was used to identify aberrant expression of sialyltransferase (ST) family members in FTC. Aberrant high expression of alpha-2,6-sialyltransferase 2 (ST6GAL2) was demonstrated to promote tumorigenesis of FTC in vitro and in vivo. Furthermore, ST6GAL2 promoted tumorigenesis by inactivating the Hippo signaling pathway. Resveratrol is a native compound extracted from Vitis species, and many studies have confirmed its protective cardiovascular and antineoplastic effects. Here we found that resveratrol can inhibit the tumorigenesis of FTC by suppressing the expression of ST6GAL2, further activating the Hippo pathway. In summary, this study revealed the role of the ST6GAL2-Hippo signaling pathway in FTC tumorigenesis and indicated that resveratrol, a commonly found antineoplastic compound, could inhibit tumorigenesis of FTC by regulating the abovementioned pathways. Keywords: follicular thyroid carcinoma, resveratrol, Hippo signaling pathway, sialyltransferase families

In 2019–2020, an array weather radar (AWR) network consisting of seven X-band phased-array radars (PARs), with a detection spatial resolution of 30 m and a temporal resolution of 30 s, was built in the city of Foshan in China’s Guangdong Province. The detection time deviation in the same space is within 5 s. Through variational data assimilation, the three-dimensional wind field inside the storm can be obtained. This study selected instances of hail, thunderstorms, strong winds, and short-duration heavy precipitation in 2020 to conduct a detailed analysis. The results show the following: (1) The fine detection ability enables phased-array radars to detect the complete evolution process of convective storms, including development, strengthening, and weakening, providing a useful reference for judging the future variation trends of convective storms. (2) Through evolutionary analysis of the three-dimensional wind field, the dynamic mechanisms of storm strengthening and weakening could be obtained, which could serve as a reference to predict the development of storms. The gust wind index and convection index calculated based on the three-dimensional wind field could provide advanced warning for nowcasting. When the gust wind index was greater than 263, the probability of gale-force wind (above 17.0 m/s) was determined to be high. Moreover, the warning could be provided 10–20 min in advance. A convection index greater than 35 and the presence of concentrated contour lines were found to be conducive to the strengthening and formation of a convection, and the warning could be provided 20 min in advance. These results show that the application of PAR can provide important technical support for nowcasting severe convective weather.

Objective: Hypoxic tumors contribute to local failure and distant metastases. Nevertheless, the molecular hallmarks of hypoxia remain ill-defined in osteosarcoma. Here, we developed a hypoxic gene signature in osteosarcoma prognoses.Methods: With the random survival forest algorithm, a prognostic hypoxia-related gene signature was constructed for osteosarcoma in the TARGET cohort. Overall survival (OS) analysis, receiver operating characteristic (ROC) curve, multivariate cox regression analysis, and subgroup analysis were utilized for assessing the predictive efficacy of this signature. Also, external validation was presented in the GSE21257 cohort. GSEA was applied for signaling pathways involved in the high- and low-risk samples. Correlation analyses between risk score and immune cells, stromal/immune score, immune checkpoints, and sensitivity of chemotherapy drugs were performed in osteosarcoma. Then, a nomogram was built by integrating risk score, age, and gender.Results: A five-hypoxic gene signature was developed for predicting survival outcomes of osteosarcoma patients. ROC curves confirmed that this signature possessed the well predictive performance on osteosarcoma prognosis. Furthermore, it could be independently predictive of prognosis. Metabolism of xenobiotics by cytochrome P450 and nitrogen metabolism were activated in the high-risk samples while cell adhesion molecules cams and intestinal immune network for IgA production were enriched in the low-risk samples. The low-risk samples were characterized by elevated immune cell infiltrations, stromal/immune scores, TNFRSF4 expression, and sensitivity to cisplatin. The nomogram accurately predicted 1-, 3-, and 5-years survival duration.Conclusion: These findings might offer an insight into the optimization of prognosis risk stratification and individualized therapy for osteosarcoma patients.

Consumer reviews are important information that reflects the quality of E-commerce goods and services and their existing problems after shopping. Due to the possible differences in consumers' experiences with goods and service quality, consumer reviews can involve multiple-aspect expressions of emotions or opinions. This may result in attitudes expressed by a consumer in the same review sometimes having a variety of emotions. We introduce a sentiment multiclassification method based on a directed weighted model. The model represents the sentiment entity vocabulary as the sentiment nodes and represents the relation between nodes as the directed weighted link. The sentiment entity vocabulary is the entity with attributes, which can express sentiment meaning in related reviews. Directed weighted links represent the sentiment similarity between two nodes of entities with attributes and determined by the direct correlation calculation between them. The paths are all connected directed links from one node to another, which are composed of several nodes and links with close sentiment similarity. Then, we can establish a directed weighted model concerning the sentiments. Directed weighted links having similar sentiment relations with each other may constitute a directed weighted path. There are several directed weighted paths from a start node to the end nodes of the sentiment entity vocabulary in the directed weighted model. Each different path is a different sentiment expression, which represents a different sentiment type. The different sentiment classifications can be obtained through the restriction of path length. Experiments and analysis of the results show that the sentiment multiclassification model based on the directed weighted model proposed in this paper can classify the review sentiments according to different limited threshold rules. Comprehensive analysis indicates the classification results have good accuracy and high efficiency.

Safety and overall productivity of the complex mechanical system (CMS) are affected by their health state directly. In order to achieving accurate and effective health state evaluation (HSE) of the CMS, dependency and correlation among system, subsystem, component, failure mode and characteristic variable are revealed. Based on their dependency and correlation between failure mode and characteristic variable, two novel concepts, including occurrence probability of failure mode (OPFM) and degradation probability of characteristic quantity (DPCQ), are defined and their calculation function relation is established for the HSE of the CMS. A framework for HSE of the CMS based on the OPEM is proposed. This HSE method can deal with the CMS with characteristics such as the small number of characteristic quantity corresponding to a single failure mode, health state, the correlation between failure mode and characteristic quantity and so on. For quantitative HSE of the CMS,“failure mode-component-subsystem-system” can be realized by step-by-layer solution. Finally, this method has been verified by a case study, which can effectively avoid problems of redundancy of characteristic quantity, wrong selection of characteristic quantity, complex calculation relation and large amount of calculation data in the HSE of the CMS.

Abstract This work aims to explore the overflow characteristics of a vertical H2S‐containing natural gas well. A two‐phase flow model for H2S‐containing natural gas well combining with a transient temperature prediction model was established to simulate the overflow process of a vertical H2S‐containing natural gas well. The model was validated by reproducing the field data of Well Longhui #2. The effects of H2S content, mud displacement, drilling fluid density, geothermal gradient, and reservoir permeability on the overflow characteristics of a vertical H2S‐containing natural gas well were studied and analyzed in this work. Results indicate that bubble, slug, and churn flows constitute the main flow patterns in the whole overflow process. The higher the H2S content is, the more obviously the gas void fraction increases. The phase change position of H2S is closer to the wellhead at lower H2S content. An increase in mud displacement indicates the decreases in overflow time. As drilling fluid density increases, the release position of H2S moves up, and the overflow time and shut‐in casing pressure increase. The initial gas void fraction is higher and the gas invasion volume will be larger in gas reservoirs with higher permeability. As the reservoir permeability increases, the shut‐in casing pressure rises while the overflow time declines. With higher geothermal gradient, the wellbore temperature tends to be higher at the same depth, leading to an increase in the H2S solubility. The gasification starting position is further away from the wellhead at higher geothermal gradient. The results of this work could provide important theoretical basis and technical guidance for drilling engineers to reduce a blowout risk during drilling of H2S‐containing natural gas well.

To select reasonable excavating and crushing process parameters and nozzle structure parameters is one of the key factors to realize commercial excavation of marine natural gas hydrate (hereinafter “hydrate” for short) in solid fluidization exploitation. For analyzing the factors influencing jet crushing efficiency of hydrate in actual engineering, nozzle diameter, pump pressure and other parameters were simulated and analyzed in k–ε turbulence model based on the laboratory experiments and the field production test data at Liwan 3 Station in the northern South China Sea with a gas production rate of 120 thousand m3/d as the target of commercial hydrate exploitation. And the following research results were obtained. First, the relationship curves of nozzle diameter, pump pressure and displacement are determined when the critical jet speed for crushing hydrate is 24 m/s. Second, the crushing rate to satisfy the daily hydrate sediment excavation of commercial exploitation is 2.48 m3/min and its corresponding jet crushing diameter is 800 mm. Third, when the nozzle diameter is fixed, other parts in the process will be damaged if jet displacement and pump pressure are increased directly. In conclusion, these selected design parameters for commercially excavating and crushing marine non-diagenetic hydrate by means of solid fluidization are conducive to the optimal design of crushing parameters of hydrate in solid fluidization exploitation. Keywords: Natural gas hydrate, Solid fluidization, Nozzle, Fluent, Water jet, Critical crushing rate, Pump pressure, Displacement, Optimal design

This study aimed to explore the potential effects of novel non-coding ribose nucleic acids (ncRNAs) in patients with multiple myeloma (MM). The gene expression profile of plasma cells was used for sequence analysis to explore the expression pattern of ncRNAs in MM. The expression patterns of non-coding RNAs in MM were analyzed by RNA sequencing (whole-transcriptome-specific RNA sequencing). Next, the expression of the selected ncRNAs was verified by quantitative real-time polymerase chain reaction. Further, the lncRNA-associated competitive endogenous RNA network in MM was elucidated using deep RNA-seq. Differentially expressed (DE) ncRNAs were significantly regulated in patients with MM. DE target lncRNAs were analyzed by cis and trans targeting prediction. Two new lncRNAs were shown to be related to MM oncogenes. MSTRG.155519 played a carcinogenic role in myeloma by targeting CEACAM1; MSTRG.13132 was related to FAM46C. Finally, the network of lncRNA–mRNA–miRNA in MM was constructed in this study. The expression of non-coding RNAs through sequence and functional analyses might be helpful for further studies on the pathogenesis of MM and the development of new MM-targeted therapy for non-coding RNAs.

The pressure-controlled injection tool (PCIT) is the key equipment in the process of high-pressure water jet fragmentation in the solid fluidization exploitation of deep-sea natural gas hydrate (NGH). The internal flow field erosion wear numerical simulation model of PCIT is established through computational fluid dynamics software to study the influence law and main factors of the drilling fluid erosion wear of PCIT. The influence laws of different drilling fluid physical parameters and different structural parameters on PCIT erosion wear were analyzed based on the Euler–Lagrangian algorithm bidirectional coupled discrete phase model (DPM) and the solid–liquid two-phase flow model. The results show that the easily eroded areas are the cone of the sliding core, the plug transition section, the plug surface, and the axial flow passage. The sliding core inlet angle and solid particle size are the main factors affecting the PCIT erosion rate. When the inlet angle of the sliding core is 30°, the diameter of solid-phase particles in drilling fluid is less than 0.3 mm, and the erosion degree of the PCIT could be effectively reduced. The research results can provide guidance for the design and application of the PCIT and advance the early realization of the commercial exploitation of hydrate.

ObjectiveTo investigate the prognostic value of t(11;14) for de novo multiple myeloma (MM) patients in novel agent era.MethodsA total of 455 patients with fluorescence in situ hybridization (FISH), before treatments from three hospitals in China, were included in the study. All patients received autologous stem cell transplantation (ASCT) after induction therapy as consolidation. High risk (HR) cytogenetics were defined as t(4;14), t(14;16), and/or del 17p.ResultsA total of 152 patients were in the HR group. Of patients without HR cytogenetics, 55 were in the t(11;14) group, and 248 were in the standard risk (SR) group without t(11;14). Gain in 1q21 was observed in 38.9% patients with t(11;14). There were no differences in median progression free survival (PFS) and overall survival (OS), respectively, between patients in the t(11;14) group and those in the SR group. Patients in the t(11;14) group had the longer median PFS and OS, respectively, compared with those in the HR group. Regardless of coexisting with 1q21 gain or not, patients in the t(11;14) group still had similar median PFS and OS compared to those in the SR group. Finally, multivariate analysis indicated that including 1q21 gain and bone marrow plasma cell with CD20 expression, no variables were found to predict the outcome of the t(11;14) group in our cohort.ConclusionsThese results confirm that outcomes of t(11;14) MM are similar to standard risk patients when they receive novel agent induction therapy consolidated by ASCT. Gain of 1q21 coexists with t(11;14) frequently. In addition, both bone marrow plasma cell with CD20 expression and 1q21 gain have no impact on median PFS or OS for patients with t(11;14).

Objective This study was performed to investigate the clinical features, risk factors, and outcomes of bone and joint tuberculosis in patients undergoing dialysis. Methods We systematically reviewed the medical records of 17 patients with bone and joint tuberculosis undergoing dialysis who were admitted to our hospital from January 2009 to January 2019. Results Seventeen patients with bone and joint tuberculosis undergoing dialysis were identified in this retrospective study, and 13 patients were undergoing hemodialysis. The mean age of the 17 patients was 61.3 years (range, 32–82 years), and 10 (58.9%) patients were male. Most of the patients had a low CD4+ cell count and low hemoglobin and albumin levels. Surgery was performed in 6 patients (35.3%), and 13 of the 17 patients (76.4%) were cured. Three patients had bone or spine sequelae, mainly because of a delayed diagnosis, and one patient died of heart failure. Conclusion These findings indicate that older age, a low CD4+ cell count, and low hemoglobin and albumin levels are possible risk factors for bone and spine tuberculosis in patients undergoing dialysis. If diagnosed early, most patients should have a good outcome after anti-tubercular therapy with or without surgery.

The context of a sentence is composed of a limited number of words. This leads to the feature sparsity problem whereby the sentence's meaning is easily influenced by language phenomena such as polysemy, ambiguity and puns. To resolve these problems, the set space model (SSM) uses language characteristics to group features of a sentence into different sets. Afterwards, the proposed feature calculus is used to capture the structural information of the sentence. Experiments have shown that this approach to the relation recognition task is effective. However, at least three weaknesses remain. First, due to the lack of a probabilistic explanation, several aspects of SSM (e.g., filter selection) have not yet been covered. Second, the existing studies have only provided an outline of SSM, and many issues remain unclear. To understand this approach, it is necessary to discuss a suitable example in detail. Third, SSM has been applied only to the task of relation recognition. Case studies of more typical topics (e.g., named entity recognition) will help illustrate the use of SSM's methodology to manipulate features. This paper develops SSM to cover these problems. It describes a systematic and novel approach to manipulating features of a sentence. In the experimental part, two typical information extraction tasks are performed to demonstrate SSM's capabilities. Two case studies are considered, and favorable improvements are observed. All of the obtained results surpass those of compared approaches. The experiments also show the influence of sentence structural information on information extraction.

Marine natural gas hydrate (NGH) reservoirs in China are characterized by shallow burial depth and weak cementing. In view of these characteristics, it is in an urgent need to develop a series of technologies and support tools to ensure safe, economical, green and efficient NGH exploitation. In this paper, a new technical idea of NGH jet breaking and fluidization exploitation without changing the temperature and pressure conditions of NGH reservoirs was proposed, and the support nozzle tools for NGH jet breaking was designed, experimentally tested and optimized. Then, the relationships between the jet breaking parameters of nozzles (e.g. working pressure drop, flow rate, and lifting and lowering velocity and frequency) and the borehole diameters and breaking rates of broken NGH were investigated based on laboratory tests, and the field construction engineering charts of NGH jet breaking and fluidization exploitation were established. Finally, this method was practically verified at Well Liwan 3 in the South China Sea. And following research results were obtained. First, the NGH jet breaking and fluidization exploitation technology can increase the production efficiency of NGH exploitation, protect the safety of reservoir bottom and reduce the energy consumption of NGH exploitation. Second, by using the nozzle tools of NGH jet breaking, the generated borehole diameters are regular, broken particles can flow back well, and the lowering velocity of jet breaking without pilot holes is less than 7.1 m/h. Third, the engineering charts of NGH jet breaking and fluidization exploitation interpret the influential laws of jet breaking behaviors and construction parameters on the borehole diameters and breaking rates of NGH so as to provide a reference for the selection of NGH production test technology parameters. And fourth, the successful implementation of the NGH jet breaking and fluidization technology in the production tests of Well Liwan 3 verifies the feasibility of NGH jet breaking and fluidization exploitation process, and exhibits its promising application prospects in NGH future commercial exploitation. Keywords: Natural gas hydrate (NGH), Jet breaking, Fluidization exploitation, Multi-functional nozzle, Breaking effect, Technological parameter, Construction chart, Production test, South China sea, Well Liwan 3

Deep-sea hydrate has great commercial exploitation value as a new type of energy, due to huge reserves, wide distribution, cleanliness, and lack of pollution. Accurately, prediction of the mechanical properties of hydrate reservoirs is a key issue for safe and efficient exploitation of deep-sea hydrate. Although there have been some experimental and numerical simulation studies on the borehole stability of the hydrate layer, the influence of temperature and flow on the decomposition of reservoir hydrate is still not well understood. There have been few pure mechanical studies on the stress and strain state of the hydrate formation around the well, and it is impossible to intuitively understand the influence of the wellbore on the original stress state of the hydrate formation. This paper therefore uses a discrete element method to establish a deep-water shallow hydrate reservoir borehole stability model and compares the discrete element numerical model with an elastoplastic analytical model of borehole stability to verify the reliability of the numerical model. A simulation study on the influence of factors such as reservoir depth and hydrate saturation on wellbore stability is carried out. The simulation results effectively present the constitutive characteristics of strain softening of hydrate sediments. According to the different mechanical characteristics, the near-well zone can be divided into a plastic strain softening zone, a plastic strain hardening zone, and an elastic zone. Reservoir depth and hydrate saturation are found to change the stress state near the well. The greater the depth and the lower the hydrate saturation, the greater the borehole shrinkage. The diameter of the optimal horizontal well in the goaf is in the range from 0.6 to 1.2 m.

The spiral separator is an important tool for desanding in natural gas hydrate production, and the change of hydrate reservoir parameters has a great impact on spiral separator behavior. Mastering the influence law is helpful to improve the separation performance. Until now, there was still no detailed analysis of the effect mechanism between reservoir parameters and spiral separator behavior. In this paper, a downhole spiral separator was designed. Then, the effects of reservoir parameters (particle size, hydrate, volume fraction, and sand volume fraction) on separation performance (discrete phase distribution, separation efficiency, and differential pressure) with different flow rates were investigated by numerical simulation method Fluent 18.0. The results show that effects degree of reservoir parameters is in order from large to small: sand phase volume fraction, particle size, hydrate volume fraction. As the particle size increases, the separation performance is improved. When the sand volume fraction increases, the natural gas hydrate (NGH) recovery efficiency and differential pressure both increase, but the sand removal efficiency decreases. When the hydrate fraction increases, the separation performance change law is opposite to that when the sand volume fraction increases. In addition, with increasing the flow rate, the efficiency and differential pressure increase. Therefore, reservoir saturation and porosity can balance NGH recovery efficiency and sand removal efficiency. Furthermore, the spiral separator has good performance under the change of reservoir parameters. The performance of the NGH spiral separator can be also maintained by increasing the flow rate.

The theoretical analysis of sediment scour in vertical direction caused by a vertical suction inlet is presented here. The predictive formulas of the critical inlet height of particle initial motion and scour depth in equilibrium state are expressed as Froude type relations based on the phenomenological theory of turbulence and the momentum transfer hypothesis between fluid and grain. The experimental data of the literature shows good consistency with the theoretical relationship, and the physical mechanism is clear. In addition, the discussion for the applicability of the predictive formula in an extensive range of Reynolds numbers reveals that the sediment incipient motion can be excellently explained by the energy spectrum of the phenomenological theory. Then the theoretical errors in different flow regions are investigated. The research presents universal relevance and reference value for similar research and application.

In order to improve the recovery efficiency of natural gas hydrate in solid-state fluidized mining of natural gas hydrate, we solve drilling safety problems, such as narrow density of natural gas hydrate formation pressure window and poor wellbore stability caused by high upstream velocity during drilling and production. In this study—in order to increase the natural gas hydrate output and reduce production costs—based on the principle of the solid-state fluidized mining, a natural gas hydrate drilling method based on double-layer continuous-pipe double-gradient drilling was proposed to solve the above problems. The article introduces a drilling and production tool combination scheme and the mathematical model of wellbore-pressure dynamic regulation. Simulation software was used to study and compare the migration efficiency of multiphase mixed slurries of sediment and natural gas hydrates in the horizontal section of the double-layer continuous-pipe double-gradient drilling method and traditional drilling method. The results show that the transport efficiency of the multiphase mixed slurry of sediment and natural gas hydrate in the horizontal section of the double-layer continuous-pipe double-gradient drilling method is better than the traditional drilling method under the same conditions. When the double-layer continuous-pipe double-gradient drilling method is adopted, the multiphase mixed slurry of sediment and natural gas hydrate is transported in the pipe and has the function of the submarine lift pump, which effectively avoids the problem of the stability of the shaft wall caused by excessive flow velocity. This will also be more suitable for the transportation of large-diameter particles during the solid-state fluidized mining of natural gas hydrates.

Water jet technology is a key technology in the marine natural gas hydrate (NGH) solid fluidization mining method. As an important parameter in water jet breaking NGH sediments technology, the critical breaking velocity of NGH sediments is unknown. In the present research, an orthogonal design experiment is carried out to study the critical velocity of NGH breakage by water jet, using frozen soil and sand as experimental samples. First, the time it takes to reach maximum NGH breaking depth is determined. Then, ultimate breaking distance is studied with respect to the NGH saturation, jet pressure, and nozzle diameter. Following that, the variation of critical velocity with NGH saturation is analyzed. Eventually, a formula to calculate the critical velocity for marine NGH breakage by water jet process is established, and the undetermined coefficient (η) in the formula is calibrated with the experiment data. The results show that the ultimate breaking distance is mostly achieved within 63 s. The three experimental factors in order of the effect on the ultimate breaking depth (from high to low) are NGH saturation, jet pressure, and nozzle diameter. The critical velocities for marine NGH breakage corresponding to the NGH saturations of 20%, 40,%, 6%, and 80% are 5.71 m/s, 7.14 m/s, 9.60 m/s, and 10.85 m/s, respectively. The undetermined coefficient η in critical velocity formula is 1.44 m/s.

The landing string is an important component of deepwater riserless drilling systems. Determination of the dynamic characteristics of the landing string plays an essential role in its design for ensuring its safe operation. In this paper, a dynamic model is developed to investigate the dynamic response characteristics of a landing string, where a landing string in a marine environment is modeled as a flexible slender tube undergoing coupled transverse and axial motions. The heaving motion of the drilling platform is taken as the upper boundary condition and the motion of the drilling bit caused by the interaction between the rock and the bit as the lower boundary condition. A semiempirical Morison equation is used to simulate the effect of the load imposed by the marine environment. The dynamic model, which is nonlinearly coupled and multibody, is discretized by a finite element method and solved by the Newmark technique. Using the proposed model, the dynamic responses of the displacement, axial force, and moment in the landing string are investigated in detail to find out the influences of driving depth of surface catheter, platform motion, bit movement, and marine environment on the dynamical characteristics of the landing string.

The application of a hydrocyclone to recycle NGH and desand during NGH exploitation is a novel idea. The flow field and performance of this hydrocyclone is in the frontier of the research in this field and is unclear so far. This research aimed to reveal the flow field characteristics and performance of NGH downhole hydrocyclones. In this paper, flow field, solid phase particle volume distribution and separation efficiency were investigated according to the two objectives of NGH recovery efficiency and sand removal efficiency with different inlet velocities by computational fluid simulations (CFD)-FLUENT software. The results show that the short circuit flow contributed to the recovery of NGH. Axial velocity is a decisive factor in balancing the two objectives of NGH recovery efficiency and sand removal efficiency. In addition, the same as those in traditional hydrocyclones, the static pressure, tangential velocity and turbulence intensity play key roles in separation performance, hydrocyclone performance can be improved by increasing the inlet velocity. On the other hand, most separation efficiencies were greater than 80%, when the particle size was larger than 15 µm, and the differential pressure was less than 0.6 MPa. Therefore, all the above results confirm that hydrocyclone has good performance in NGH exploitation, and the basis of its structural design and optimization are provided.

A glue stick is comprised of solidified adhesive mounted in a lipstick-like push-up tube. Whey is a byproduct of cheese making. Direct disposal of whey can cause environmental pollution. The objective of this study was to use whey protein isolate (WPI) as a natural polymer along with polyvinylpyrrolidone (PVP) to develop safe glue sticks. Pre-dissolved WPI solution, PVP, sucrose, 1,2-propanediol (PG), sodium stearate, defoamer, and preservative were mixed and dissolved in water at 90 oC and then molded in push-up tubes. Chemical composition, functional properties (bonding strength, glue setting time, gel hardness, extension/retraction, and spreading properties), microstructure, and storage stability of the prototypes were evaluated in comparison with a commercial control. Results showed that all WPI/PVP prototypes had desirable bonding strength and exhibited faster setting than PVP prototypes and control. WPI could reduce gel hardness and form less compact and rougher structures than that of PVP, but there was no difference in bonding strength. PVP and sucrose could increase the hygroscopicity of glue sticks, thus increasing storage stability. Finally, the optimized prototype GS3 (major components: WPI 8.0%, PVP 12.0%, 1,2-propanediol 10.0%, sucrose 10.0%, and stearic sodium 7.0%) had a comparable functionality to the commercial control. Results indicated that whey protein could be used as an adhesive polymer for glue stick formulations, which could be used to bond fiber or cellulose derived substrates such as paper.

This paper analyzes the evolution of video technology, studies of analog and digital development of network technology, analyzes the advantages and disadvantages comparison of different network technology, describes using the city optical network based on PON technology has more advantages in the application of video monitoring network system. At the same time, it is concerned about the operation and maintenance and technical problems and explore solutions of PON to carry video system.

The inserted sealing tool is a critical downhole implement that is used to balance the downhole pressure in multistage fracturing operations and prevent fracturing fluid from overflow and/or backward flow. The sealing ring of an inserted sealing tool plays an important role in downhole sealing since a sealing failure would ail the fracturing operation. In order to improve the sealing performance and reduce the potential fracturing failures, this research aims to investigate the influence of V-shaped sealing ring geometries on sealing performance. Constitutive experiments of rubber materials were carried out and the parameters of the constitutive relationship of rubber materials were obtained. A two-dimensional axisymmetric model considering the sealing ring has been established and influences are investigated with considerations of various system parameters and operating conditions. It is found that the stresses concentrated at the shoulder and inner vertex of the sealing ring have direct impact on the damage of the sealing rings under operational conditions. Moreover, the sealing interference, among several other factors, greatly affects the life of the sealing ring. A new design of the sealing ring is suggested with optimized geometric parameters. Its geometric parameters are the edge height of 5 mm, the vertex angle of 90°–100°, and the interference of 0.1 mm, which show a better performance and prolonged operation life of the sealing ring.

The influence of spring stiffness and valve quality on the motion behaviors of reciprocating plunger pump discharge valves was investigated by fluid structure interaction (FSI) simulation and experimental analysis. The mathematical model of the discharge valve motion of a 2000-fracturing pump was developed and the discrete differential equations were solved according to FSI and results obtained by ANDINA software. Results indicate that spring stiffness influences the maximum lift, the opening resistance and shut-off lag angle, as well as the fluid velocity of the clearance, the impact stress and the volume efficiency of the pump valve in relation to the valve quality. An optimal spring stiffness parameter of 14.6 N/mm was obtained, and the volumetric efficiency of the pumping valve increased by 4‰ in comparison to results obtained with the original spring stiffness of 10.09N/mm. The experimental results indicated that the mathematical model and FSI method could provide an effective approach for the subsequent improvement of valve reliability, volumetric efficiency and lifespan.

Amplitude changes in the P-wave of intracavitary electrocardiography have been used to assess the tip placement of central venous catheters. The research assessed the sensitivity and specificity of this sign in comparison with standard radiographic techniques for tip location, focusing on factors influencing its clinical utility. Both intracavitary electrocardiography guided tip location and X-ray positioning were used to verify catheter tip locations in patients undergoing central venous catheter insertion. Intracavitary electrocardiograms from 1119 patients (of a total 1160 subjects) showed specific amplitude changes in the P-wave. As the results show, compared with X-ray positioning, the sensitivity of electrocardiography-guided tip location was 97.3%, with false negative rate of 2.7%; the specificity was 1, with false positive rate of zero. Univariate analyses indicated that features including age, gender, height, body weight, and heart rate have no statistically significant influence on P-wave amplitude changes (P > 0.05). Multivariate logistic regression revealed that catheter insertion routes (OR = 2.280, P = 0.003) and basal P-wave amplitude (OR = 0.553, P = 0.003) have statistically significant impacts on P-wave amplitude changes. As a reliable indicator of tip location, amplitude change in the P-wave has proved of good sensitivity and excellent specificity, and the minor, zero, false positive rate supports the clinical utility of this technique in early recognition of malpositioned tips. A better sensitivity was achieved in placement of centrally inserted central catheters (CICCs) than that of peripherally inserted central catheters (PICCs). In clinical practice, a combination of intracavitary electrocardiography, ultrasonic inspection and the anthropometric measurement method would further improve the accuracy.