Search

Breast cancer is the most common and deadly type of cancer in the world. Based on machine learning algorithms such as XGBoost, random forest, logistic regression, and K-nearest neighbor, this paper establishes different models to classify and predict breast cancer, so as to provide a reference for the early diagnosis of breast cancer. Recall indicates the probability of detecting malignant cancer cells in medical diagnosis, which is of great significance for the classification of breast cancer, so this article takes recall as the primary evaluation index and considers the precision, accuracy, and F1-score evaluation indicators to evaluate and compare the prediction effect of each model. In order to eliminate the influence of different dimensional concepts on the effect of the model, the data are standardized. In order to find the optimal subset and improve the accuracy of the model, 15 features were screened out as input to the model through the Pearson correlation test. The K-nearest neighbor model uses the cross-validation method to select the optimal k value by using recall as an evaluation index. For the problem of positive and negative sample imbalance, the hierarchical sampling method is used to extract the training set and test set proportionally according to different categories. The experimental results show that under different dataset division (8 : 2 and 7 : 3), the prediction effect of the same model will have different changes. Comparative analysis shows that the XGBoost model established in this paper (which divides the training set and test set by 8 : 2) has better effects, and its recall, precision, accuracy, and F1-score are 1.00, 0.960, 0.974, and 0.980, respectively.

Due to the excellent heat transfer performance and low pressure drop, the parallel-plate regenerator (PPR) is very suitable for use in Stirling engines. At present, researches on the application of...

A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

ObjectivesTo investigate the clinical efficacy of long-term of low-dose inhaled glucocorticoid (ICS) in the treatment on children with bronchial asthma, and to evaluate its effects on the height, weight and expression of serum insulin-like growth factor of children with bronchial asthma.Methods91 children with bronchial asthma treated in our hospital from January 2017 to December 2017 were chosen, and 31 healthy children without asthma history in our hospital were selected as the control group (Group C); For the different treatment methods comparison, 91 children with bronchial asthma were divided into treatment group A (48 children) and treatment group B (43 children) randomly. In treatment group A, children were treated with low-dose ICS for more than 1 year; in treatment group B, children were treated with low-dose ICS for less than 1 year or received low-dose ICS for less than 2 months/year. For treatment evaluation, the asthma control test (C-ACT) were scored at 0 months, 12 months and 24 months in three groups, and the height and weight of children, the levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) in serum in each group were also measured.ResultsIn the control group, the C-ACT scores were increased with time (P0.05); there was no significant difference in the expression levels of IGF-1 and IGFBP-3 in serum between treatment group and control group (P>0.05).Compared with the C-ACT scores in treatment group A and treatment group B at 0 month, the C-ACT scores were significantly higher at 12 months and at 24 months, and there was a statistical difference among 0 month, 12 months and at 24 months in treatment group A and treatment group B (PConclusionsTreatment for children with bronchial asthma by long-term use of low-dose ICS is safe and effective, it does not affect health and development of children with bronchial asthma; children with bronchial asthma were treated with low-dose ICS for more than 1 year had a better effective than children were treated with low-dose ICS for less than 1 year or received low-dose ICS for less than 2 months/year.

Background: We aimed to evaluate the accuracy of quick Sequential (sepsis-related) Organ Failure Assessment (qSOFA) for the diagnosis of sepsis-3, and to analyze the prognosis of infected patients in wards over-diagnosed with qSOFA but missed by sepsis-3, and those missed by qSOFA but in accordance with sepsis-3 criteria. We also intended to validate the performance of qSOFA as one predictor of outcome in patients with suspicion of infection. Methods: We reviewed the medical records of 1716 adult patients with infection who were hospitalized from July 1 st , 2012 to June 30 th , 2014 in the Yuetan subdistrict of Beijing, China. Based on the sepsis-3 criteria and qSOFA score proposed by the Third International Consensus Definitions for Sepsis and Septic Shock, these patients were categorized into four groups: qSOFA(−)sepsis(−), qSOFA(+)sepsis(−), qSOFA(−) sepsis(+), and qSOFA(+)sepsis(+). Multivariate logistic regression analysis was used to determine the independent risk factors for in-hospital mortality. The area under the receiver operating characteristic curves (AUROCs) of the qSOFA(+) group were compared with the sepsis(+) group for in-hospital mortality, ICU admission, and invasive ventilation. Results: Among the 1,716 patients with infection, there were 935 patients (54.5%) with sepsis, and 640 patients (37.3%) with qSOFA ≥2. There were 610 patients in the qSOFA(−)sepsis(−) group, 171 in the qSOFA(+)sepsis(−) group, 466 in the qSOFA(−)sepsis(+) group, and 469 in the qSOFA(+)sepsis(+) group. In the logistic regression analysis, increasing age, bedridden status, and malignancy were all independent risk factors of hospital mortality. Sepsis and qSOFA ≥2 were also independent risk factors of hospital mortality, with an adjusted OR of 3.85 (95% CI: 2.70–5.50) and 13.92 (95% CI: 9.87–16.93) respectively. qSOFA had a sensitivity of 50.2% and a specificity of 78.1% for sepsis-3. The false-positive [qSOFA(+)sepsis(−)] group had 38 patients (22.2%) die during hospitalization, and an adjusted OR of 9.20 (95% CI: 4.86–17.38). In addition, the false-negative [qSOFA(−)sepsis(+)] group had a hospital mortality rate of 7.3% (34/466) and an adjusted OR of 2.59 (95% CI: 1.39–4.83). In comparison, patients meeting neither qSOFA nor sepsis criteria had the lowest hospital mortality [2.6% (16/610)], whereas patients with both qSOFA ≥2 and sepsis had the highest hospital mortality [56.5% (265/469)], with an adjusted OR of 42.02 (95% CI: 24.31–72.64). The discrimination of in-hospital mortality using qSOFA (AUROC, 0.846; 95% CI, 0.824–0.868) was greater compared with sepsis-3 criteria (AUROC, 0.834; 95% CI, 0.805–0.863; P Conclusions: In our analysis, the sensitivity(Se) of qSOFA for the diagnosis of sepsis was lower, and qSOFA score ≥2 might identify a group of patients at a higher risk of mortality, regardless of being septic or not.

Background: To increase the utilization of Community Health Service (CHS) centers for primary care, the Central Government of China has promoted the use of contracts—known as “service agreements” (SAs)—between patients and primary care physicians. This study sought to identify factors that predict who signed SAs and the association between SAs and frequency of primary care visits in a CHS center in Beijing. Methods: Four years of electronic health record (EHR) data (2015 to 2018) were analyzed. Multivariate logistic regression analysis was performed to examine the tendency of patients to establish a SA. The pattern of the primary care visits between the SA and the non-SA groups was compared using Gamma regression models, controlling for demographic and comorbidity conditions. Contrast analysis was performed to assess the odds ratios of signing SAs among levels of a specific patient characteristic. Results: Data from 32,682 adult CHS patients were collected. Of those, 66.4% had signed a SA. Patients who were female, older, more educated, married, employed, insured, or had comorbid conditions were more likely to sign SAs. Overall, having a SA was associated with a higher frequency of primary care visits for women and older patients, but not for the young and educated patients. Conclusions: The evidence provides an important consideration for reducing gaps in the use of primary care services during the nationwide transition from the fee-for-service specialty care system to the patient-centered primary care-driven medical home model.

Additional file 1: Table S1. Imputation of missing data for the calculation of SOFA or eSOFA score. eResults. Detailed Description of eSOFA/SOFA score of the 98 eSOFA+/Sepsis-3− patients. Table S2. Frequency of SOFA/eSOFA organ dysfunctions in patients meeting Sepsis-3 or eSOFA criteria. Figure S1. Frequency of SOFA or eSOFA organ dysfunctions in Sepsis-3+/eSOFA+ sepsis patients. Table S3. Risk models of in-hospital mortality.

Xue-Lian Zhang,1 Ming-Xia Yuan,1 Gang Wan,2 Guang-Ran Yang,1 Dong-Mei Li,3 Han-Jing Fu,1 Liang-Xiang Zhu,1 Rong-Rong Xie,1 Jian-Dong Zhang,4 Yu-Jie Lv,5 Yu-Ling Li,6 Xue-Ping Du,7 Zi-Ming Wang,8 Xue-Li Cui,9 De-Yuan Liu,10 Ying Gao,11 Shu-Yan Cheng,12 Qian Wang,13 Yu Ji,14 Guang-Wei Li,15,16 Shen-Yuan Yuan1 1Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, People’s Republic of China; 2Medical Records and Statistics Department, Beijing Ditan Hospital, Capital Medical University, Beijing, People’s Republic of China; 3Clinical and Translational Science Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA; 4Department of General Practice, Jinsong Community Health Service Center, Beijing, People’s Republic of China; 5Department of General Practice, Cuigezhuang Community Health Service Center, Beijing, People’s Republic of China; 6Department of General Practice, Xinjiekou Community Health Service Center, Beijing, People’s Republic of China; 7Department of General Practice, Yuetan Community Health Service Center of Fuxing Hospital, Capital Medical University, Beijing, People’s Republic of China; 8Department of General Practice, Jiangtai Community Health Service Center, Beijing, People’s Republic of China; 9Department of General Practice, Sanlitun Community Health Service Center, Beijing, People’s Republic of China; 10Department of General Practice, Zuojiazhuang Community Health Service Center, Beijing, People’s Republic of China; 11Department of General Practice, The First People’s Hospital of Chongwen District, Beijing, People’s Republic of China; 12Department of General Practice, Balizhuang Community Health Service Center, Beijing, People’s Republic of China; 13Department of General Practice, Majiapu Community Health Service Center, Beijing, People’s Republic of China; 14Department of Endocrinology, Beijing Aerospace General Hospital, Beijing, People’s Republic of China; 15Department of Endocrinology, China-Japan Friendship Hospital, Beijing, People’s Republic of China; 16Center of Endocrinology and Cardiovascular Disease, Department of Endocrinology, National Center of Cardiology and Fuwai Hospital, Beijing, People’s Republic of China Objective: It is well known that diabetic kidney disease is a risk factor for cardiovascular diseases (CVD) in patients with type 2 diabetes mellitus (T2DM). In this study, the effects of urine albumin excretion rate (AER) and estimated glomerular filtration rate (eGFR) on CVD outcomes were analyzed in a population of T2DM. Methods: The study was carried out using recorded information of a cohort study. A total of 1,914 patients with T2DM with no prevalent CVD were enrolled in an 8 years prospective study and received multifactorial intervention. The risk of CVD outcomes was assessed according to chronic kidney disease staging, which was categorized using AER (mg/d) and eGFR (mL/min/1.73 m2). The effects of AER and eGFR on risk of CVD onset were also analyzed. Results: During the follow-up period (median 6.8 years), 71 CVD events occurred. At baseline, those with AER ≥300 mg/d and coexisting eGFR 60–89 mL/min/ 1.73 m2 or

The two-equation model in porous media can describe the local thermal non-equilibrium (LTNE) effects between fluid and solid at REV scale, with the temperature differences in a solid particle neglected. A multi-scale model has been proposed in this study. In the model, the temperature differences in a solid particle are considered by the coupling of the fluid energy equation at REV scale with the heat conduction equation of a solid particle at pore scale. The experiments were conducted to verify the model and numerical strategy. The multi-scale model is more suitable than the two-equation model to predict the LTNE effects in porous media with small thermal conductivity. The effects of particle diameter, mass flow rate, and solid material on the LTNE effects have been investigated numerically when cryogenic nitrogen flows through the porous bed with small thermal conductivity. The results indicate that the temperature difference between solid center and fluid has the same trend at different particle diameters and mass flow rates, while the time to reach the local thermal equilibrium is affected by solid diameter dramatically. The results also show that the temperature difference between solid center and surface is much greater than that between solid surface and fluid. The values of $$ \rho {\text{c}} $$ for different materials have important influence on the time to reach the local thermal equilibrium between solid and fluid.

Background The US Centers for Disease Control and Prevention (CDC) recently released simplified eSOFA organ dysfunction criteria of Adult Sepsis Event for sepsis surveillance in the US. Our study aimed to compare the prevalence, characteristics, and outcomes of sepsis patients identified by eSOFA criteria versus Sequential Organ Failure Assessment (SOFA) Score (Sepsis-3) and assess the external validity of eSOFA criteria in China. Methods We conducted a retrospective cohort study of adult residents of Yuetan Subdistrict, Beijing, China, who were hospitalized from July 1, 2012 to June 30, 2014. Among patients with infection, sepsis was identified if there was a concurrent rise in SOFA score by 2 or more points (Sepsis-3) or the presence of 1 or more eSOFA criteria: vasopressor initiation, mechanical ventilation initiation, doubling in creatinine, doubling in bilirubin to 2.0 mg/dL or above, 50% or greater decrease in platelet count to less than 100 cells/μL, or lactate equal to or above 2.0 mmol/L. Areas under the receiver operating characteristic curves (AUROCs) for in-hospital mortality were compared between sepsis patients detected by the two criteria, adjusting for baseline characteristics. Results Of 1716 hospitalized patients with infection, 935 (54.5%) met Sepsis-3 criteria, 573 (33.4%) met eSOFA criteria, while 475 (27.7%) met both criteria. Demographic and clinical characteristics of sepsis patients meeting Sepsis-3 or eSOFA criteria were similar. In-hospital mortality was higher with eSOFA criteria versus Sepsis-3 (46.6% vs. 32.0%, p p p = 0.097). The predicted probability for in-hospital mortality was higher with eSOFA criteria versus Sepsis-3 (AUROC 0.830 vs. 0.795, p = 0.001) adjusting for baseline characteristics. Conclusions The CDC Adult Sepsis Event’s eSOFA criteria identify a smaller, more severely ill cohort of sepsis patients with similar demographic and clinical characteristics as the more complex Sepsis-3 SOFA score. These results suggest similar performance of eSOFA criteria across diverse populations, with low sensitivity and high specificity for the diagnosis of Sepsis-3.

Fe3O4 magnetic nanoparticles were synthesized by chemical co-precipitation with sodium citrate as surfactant and were characterized by FT-IR spectrometer, X-ray diffraction and transmission electron microscopy. A novel nitrite sensor was fabricated by electropolymerization of alizarin red on the surface of glassy carbon electrode modified with Fe3O4-multiwalled carbon nanotubes composite nanofilm. Under the optimal experimental conditions, it was showed that the proposed sensor exhibited good electrocatalytic activity to the oxidation of nitrite, and the peak current increased linearly with the nitrite concentration from 9.64 x 10(-6) mol x L(-1) to 1.30 x 10(-3) mol x L(-1) (R = 0.9976) with a detection limit of 1.19 x 10(-6) mol x L(-1) (S/N = 3). This sensor showed excellent sensitivity, wide linear range, stability and repeatability for nitrite determination with potential applications.

In this study, the influence of various air inlet angles on the heat transfer and flow friction characteristics of a 2-row plain finned oval tube heat exchanger is analyzed by experimental and numerical methods. The experimental results show that an air inlet angle 45° provides the best heat transfer performance, and an air inlet angle 90° provides the smallest pressure drop, while an air inlet angle 30° provides the worst heat transfer performance associated with the largest pressure drop. The 3-D numerical simulation results indicate that with the decrease of the air inlet angle, the uniformity of the air velocity distribution in the z-direction of the heat exchanger becomes worse. The heat transfer characteristics at different air inlet angles are analyzed from the prospective of the field synergy principle and the effect of the air velocity distribution uniformity. The overall heat transfer performance is also evaluated by the JF factor under the same air mass flow rate. The results show that the air inlet angle 45° offers the best overall heat transfer performance, next is the air inlet angle 60°, while the air inlet angle 30° has the worst overall heat transfer performance.

To investigate the effect of wind deflectors on air flow and heat transfer performance of an air-cooling tower under crosswind conditions, an experimental system based on a surface condenser aluminum exchanger-type indirect air-cooling tower is established at a 1:100 proportional reduction. A 3-D computational fluid dynamics simulation model is built to study the air flow and temperature fields. The air flow rate into the cooling tower and the heat transfer rate of the radiators are used to evaluate cooling performance. Rotating wind deflectors are adopted to reduce the influence of crosswind on the cooling tower performance. The effects of the rotating wind deflectors on the thermal-hydraulic characteristics of the air-cooling tower under different environmental crosswind speeds are studied. Results indicate that the wind direction in the tower reverses as the rotating speed of the wind deflectors increases. The thermal performance of an air-cooling tower under crosswind conditions can be improved by using rotating wind deflectors. The heat transfer rate of a cooling tower with eight wind deflectors begins to increase when the rotating speed exceeds 2 r/min.

In the present study, the recent research of three kinds of surface heat exchangers, i.e., shell-and-tube heat exchangers with helical baffles, air-cooled heat exchangers used in large air-cooled systems, and primary surface heat exchangers are reviewed. They are used in the energy conversion and utilization for liquid to liquid, gas to gas and liquid to gas heat exchange, respectively. It can be concluded that the helical baffled shell-and-tube heat exchangers (STHXs) should be used to replace the conventional segmental baffled STHXs in industries, despite there are a lot of research work have to be done, especially on the novel combined helical baffles. The primary surface gas to gas heat exchangers are developing towards to the more complex 3D CC primary surfaces, such as the double-wave CC primary surface, offset-bubble primary surface and 3D anti-phase secondary corrugation. The whole performance for the air-cooled heat exchangers in the air cooling system and the multi-objectives optimization for air-cooled heat exchangers should be paid more attention, considering the heat transfer, pumper power, space usage and other economic influence factors.

Information about the epidemiology of sepsis in community residents in China remains scarce and incomplete. The purpose of this study was to describe the occurrence rate and outcome of sepsis in Yuetan Subdistrict of Beijing and to estimate the occurrence rate of sepsis in China.Retrospective cohort study.All public hospitals serving residents in Yuetan Subdistrict, Beijing.All patients (n = 1,716) meeting criteria for sepsis based on American College of Chest Physicians/Society of Critical Care Medicine consensus definition.None.We screened all adult residents in Yuetan Subdistrict who were hospitalized from July 1, 2012, to June 30, 2014, and reviewed medical records. Patients with sepsis were included in the analysis. We enrolled 1,716 patients with sepsis out of 21,191 hospitalized adults screened, among whom severe sepsis developed in 256 patients, and septic shock developed in 233 patients. The crude annual occurrence rates of sepsis, severe sepsis, and septic shock in Yuetan Subdistrict were 667, 103, and 91 cases per 100,000 population, corresponding to standardized occurrence rates of 461, 68, and 52 cases per 100,000 population per year, respectively. Both occurrence rate and mortality increased significantly with age, although males had higher age-adjusted occurrence rate and mortality. The occurrence rate of sepsis also exhibited seasonal variation, peaking in winter season. The overall hospital mortality rate of sepsis was 20.6%, yielding a standardized mortality rate of 79 cases per 100,000 population per year.Sepsis is a common and frequently fatal syndrome in Yuetan Subdistrict, Beijing. The occurrence rate and mortality of sepsis are significantly higher in males and elderly people.

The multilayer spiral-wound heat exchanger (SWHX) is used extensively in many industrial fields, but little research on the shell-side thermal-hydraulic performances in SWHXs has been performed. So an investigation on the shell-side flow and heat transfer performances of multilayer SWHXs under turbulent flow is implemented by using experimental and numerical methods. An experiment on the shell-side flow and heat transfer performance of a self-manufactured SWHX with three layers of coils is carried out under heat flux specified boundary condition (BC) to validate a numerical method. The results obtained by the simulations agree well with those from the experiment. Furthermore, to study the effects of different thermal BCs of the tube wall on the shell-side heat transfer performance in the multilayer SWHXs, numerical simulations are performed under the thermal BC of constant heat flux and constant temperature. Then the results are compared to those of the water-to-water conjugate heat transfer. It is found that the maximum relative deviation is 11.4% and 3.5%, respectively. Finally, the correlation of the shell-side Nusselt number, Nus is obtained by the Wilson plot method, which is Nus = 0.179·Res0.862, with the available range of Res from 500 to 3500.

A novel hydrogen peroxide (H2O2) biosensor was constructed based on Fe3O4 magnetic nanoparticles (MNPs) and horseradish peroxidase with graphene–chitosan composite material as a matrix. Fe3O4 MNPs were synthesised by chemical co-precipitation with sodium citrate as surfactant. Fourier transform infrared spectroscopy and transmission electron microscopy were applied for the characterisation of the obtained Fe3O4 MNPs. The conductivity of different composite films was researched by electrochemical impedance spectroscopy and the electrocatalytic properties of the H2O2 biosensor were studied by cyclic voltammetry. Under optimal conditions, experimental results indicated that the biosensor could electrocatalyse the reduction of H2O2; the reduction peak current had a good linear relationship with the concentration of H2O2 from 2.49 × 10−5 to 1.67 × 10−3 mol/l (R = 0.9990). The detection limit was 3.05 × 10−6 mol/l (S/N = 3). This novel biosensor showed good sensitivity, stability and repeatability for H2O2 detection.

Fe3O4 magnetic nanoparticles were synthesized by chemical co-precipitation with sodium citrate as a surfactant and were used with chitosan to construct a novel hydrogen peroxide sensor. The electrochemical behavior of hydrogen peroxide at the sensor was investigated by cyclic voltammetry. The composite film electrocatalyzed the reduction of hydrogen peroxide, and the peak current increased linearly with concentration from 1.00 × 10−5 to 1.00 × 10−3 mol · L−1 (R = 0.9974) with a detection limit of 1.53 × 10−6 mol · L−1. This novel nonenzyme sensor provided good sensitivity, stability, and precision with potential applications.

A novel laccase biosensor was fabricated by entrapping laccase in graphene–chitosan composite materials and applied to determine hydroquinone. The graphene–chitosan composite had good conductivity, high stability, and good biocompatibility. Laccase was firmly embedded into the composite without other cross-linking reagents. The morphology and electrical conductivity of graphene-chitosan film were measured by scanning electron microscopy and electrochemical impedance spectroscopy. This biosensor catalyzed the oxidation of hydroquinone to p-quinone and the reduction back to hydroquinone. The cathodic peak current of hydroquinone increased significantly with concentration in the range of 2.0 × 10−6 to 1.0 × 10−4 mol · L−1 (r = 0.9975) with a limit of detection of 2.6 × 10−7 mol · L−1. The response time of the biosensor to reach 95% of its steady-state current was less than 10 s. Moreover, the biosensor exhibited good stability, reproducibility, and selectivity.

By using the electrocatalytic property of the nanomaterials and the molecular recognition characteristic of neutral red (NR), a new modified electrode was fabricated by electropolymerising the NR onto the surface of the multiwalled carbon nanotubes modified glassy carbon electrode, which exhibited a good electrocatalytic activity for folic acid (FA). The results of experiments showed that a good linear relationship between the reductive peak current of FA and its concentration was in the range of 6.25 × 10−7–5.00 × 10−5 mol/l with a detection limit of 1.37 × 10−7 mol/l in the optimal conditions. The recovery ratio was in the range of 99.3 ∼ 103.2%. The composite film modified electrode exhibited an excellent stability with a simple fabrication, which established a solid foundation for the practical applications.

A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90°, 60 °, 45°, and 30°) are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90°) has the worst performance while 45° and 30° has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60°, while the best performance occurred at 45° and 90° at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

The air inlet flow direction is not orthogonal to the heat exchanger surface in many cases. To study the performance of the heat transfer and pressure drop of a heat exchanger with different air inlet angles, this paper shows the experimental system about a finned oval-tube heat exchanger inclined toward the air incoming flow direction. The heat transfer and pressure drop characteristics of four air inlet angles (90°, 60°, 45°, and 30°) are studied separately for the Reynolds number ranging from 1300 to 13000 in this study. The experimental correlations of Nusselt number and resistance coefficient of the air side are acquired. The results show that the overall heat transfer coefficients become smaller and smaller with the decrease of the air inlet angles, while the pressure drops have significant changes. The heat transfer performances of the heat exchanger under the three inclined air inlet angles are worse than that at 90°. Among the three inclined angles, the performance at 45° is the best under identi...

This work reports on a material synthesized via 1-butyl-3-methylimidazolium tetrachloroferrate and K3[Fe(CN)6]. Its structure and properties were characterized by IR, XPS, AFM and CV, which was inferred as Prussian Blue Type (PBT) material with particle size distribution between 80–120 nm and spike-like aggregation from the characterization results. PBT is insoluble in acetone, water and ethanol uniformly, which gives magnetic properties. It can be reacted with 30 % H2O2, and produce gas bubbles when a voltage is applied. Modified on the glassy carbon electrode, the material showed obviously electrocatalytic activity to sodium nitrite, which has potential application prospect for sensors.

Fe3O4 magnetic nanoparticles were synthesized by chemical co-precipitation with sodium citrate as surfactant and were characterized by FT-IR spectrometer, X-ray diffraction and transmission electron microscopy. A novel nitrite sensor was fabricated by electropolymerization of alizarin red on the surface of glassy carbon electrode modified with Fe3O4-multiwalled carbon nanotubes composite nanofilm. Under the optimal experimental conditions, it was showed that the proposed sensor exhibited good electrocatalytic activity to the oxidation of nitrite, and the peak current increased linearly with the nitrite concentration from 9.64 x 10(-6) mol x L(-1) to 1.30 x 10(-3) mol x L(-1) (R = 0.9976) with a detection limit of 1.19 x 10(-6) mol x L(-1) (S/N = 3). This sensor showed excellent sensitivity, wide linear range, stability and repeatability for nitrite determination with potential applications.

With the rapid development of the artificial intelligence (AI) techniques used in thermal systems in recent decades, more and more AI algorithms are used in the optimal design of heat exchangers. Thermal performance prediction, optimal design, and cost minimization of heat exchangers are important targets for both designers and users. In this article, four common AI methods (artificial neural network, ANN; genetic algorithm, GA; particle swarm optimization, PSO; and Taguchi method) are applied to predict and optimize the thermal performances of three common types of heat exchangers (shell-and-tube heat exchangers, STHXs; finned tube heat exchangers, FTHXs; and primary surface recuperators). It can be concluded that ANNs can be applied to predict thermal performances of the heat exchangers, especially for engineers to model the complicated heat exchangers in engineering applications. The optimized results acquired by the GA and the improved PSO methods for the comprehensive performance of heat exchangers may be used in engineering application and comprehensive study, as long as the optimization objective functions, optimization variables, and restrictive conditions can be chosen appropriately. The Taguchi method can be applied and conducted quickly and inexpensively to study the effect of the design parameters on the comprehensive performances of heat exchangers based on the CFD or experiment methods. Keywords: thermal performance; prediction; optimization; heat exchangers; artificial intelligence

Chemotherapy has significantly improved the prognosis of high-grade osteosarcoma (OS), but over 30% of OS patients can still not be cured. Pemetrexed, the newly-developed anti-folate chemotherapy drug, exerted lower efficacy against OS cells. Here, we aimed to increase pemetrexed efficiency, and found that the cell-permeable short-chain ceramide (C6) significantly enhanced pemetrexed-induced viability reduction and death in cultured OS cell lines (U2OS and MG-63). Pemetrexed induced moderate apoptosis in OS cells, which was dramatically augmented by C6 ceramide. The apoptosis inhibitor z-VAD-fmk largely inhibited C6 ceramide plus pemetrexed-induced cytotoxicity and apoptosis in OS cells. By using pharmacological and siRNA-knockdown strategies, we showed that Akt-mammalian TOR (mTOR) over-activation was an important pemetrexed resistance factor in OS cells, and C6 ceramide-mediated pemetrexed sensitization effect was mediated, at least in part, by Akt-mTOR inhibition. Finally, we found that Akt-S6 Kinase 1 (S6K1, an indicator of mTOR activation) was over-activated in human OS tissues. On the other hand, the osteoblastic MC3T3-E1 cells, which expressed lower Akt-S6K1 phosphorylation, were resistant to pemetrexed and/or C6 ceramide. Together, we conclude that C6 ceramide sensitizes pemetrexed-induced apoptosis and cytotoxicity in OS cells probably through in-activation of Akt-mTOR signaling.

Piperlonguminine (PL), a key compound from the Piper longum fruit, is known to exhibit anti‑tumor and anti‑inflammatory activities. However, little is known about its effects on collagen‑induced arthritis (CIA). Fibroblast‑like synoviocytes (FLS) have a pivotal role in the development of rheumatoid arthritis (RA). Myeloid‑derived suppressor cells (MDSCs) are able to suppress T cell responses and have important roles in the regulation of autoimmune arthritis. The current study investigated whether PL alters the progression of RA. It was determined that PL reduces the arthritis score and histopathologic lesions in a mouse model of CIA. PL also reduces the expression levels of serum anti‑collagen II antibodies (anti‑CⅡ), tumor necrosis factor‑α (TNF‑α), interleukin (IL)‑1β, IL‑23 and IL‑17 in CIA mice. In draining lymph nodes (DLNs), MDSCs were significantly expanded, however, the number of Th17 cells was markedly decreased by PL treatment. Additionally, PL reduced secretion of IL‑1β, IL‑23 and IL‑17 by TNF‑α‑stimulated human RA FLS. PL significantly inhibited the migration and invasion of TNF‑α‑stimulated human RA FLS. These results indicate that PL may be a candidate therapeutic agent for the treatment of RA, via the expansion of MDSCs and the inhibition of the Th17 response and activation of FLS.

OBJECTIVE To investigate the association between neck circumference and central obesity, overweight, and metabolic syndrome in Chinese individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS A total of 3,182 diabetic subjects (aged 20–80 years) were recruited from 15 community health centers in Beijing using a multistage random sampling approach. RESULTS Receiver operating characteristic analysis showed that the area under the curve for neck circumference and central obesity was 0.77 for men and 0.75 for women (P < 0.001). Furthermore, a neck circumference of ≥38 cm for men and ≥35 cm for women was the best cutoff point for determining overweight subjects. A neck circumference of ≥39 cm for men and ≥35 cm for women was the best cutoff point to determine subjects with metabolic syndrome. CONCLUSIONS In the present study, neck circumference is positively related with BMI, waist circumference, and metabolic syndrome in Chinese individuals with type 2 diabetes.

Inflammation plays a critical role in acute myocardial infarction (AMI) and tumor necrosis factor alpha (TNF-alpha) is a potent inflammatory trigger. This study was designed to examine the kinetics of TNF-alpha in plasma in patients with AMI and the potential benefit of inhibition of TNF-alpha monoclonal antibody in AMI.TNF-alpha levels in plasma were measured in 42 patients with AMI. TNF-alpha levels were elevated at 4 hours after onset of chest pain and declined to control values at 48 hours. TNF-alpha levels were higher in patients with Killip III and IV than in those with Killip I and II (P.01). To examine the pathogenic role of TNF-alpha, New Zealand White rabbits were treated with buffer or a TNF-alpha monoclonal antibody before left anterior descending artery (LAD) ligation. Treatment with the TNF-alpha monoclonal antibody decreased area of necrosis, number of circulating endothelial cells, and lipid peroxidation product malonaldehyde bis(dimethyl acetal). There was a significant correlation of TNF-alpha levels with peak CK-MB in AMI patients, and area of necrosis, MDA, and circulating endothelial cells in rabbits (all P.05).TNF-alpha release early in the course of AMI contributes to myocardial injury and dysfunction. Treatment with the monoclonal antibody against TNF-alpha can be cardioprotective, particularly in the setting of heart failure in patients with AMI.

Objectives: Despite optimal treatments, prognosis in acute coronary syndrome (ACS) patients with chronic kidney disease (CKD) remains poor. Elevated serum uric acid (SUA) levels may predict worse outcomes in these patients. The objective was to assess the predictive value of SUA levels on mortality in ACS patients with CKD after drug-eluting stent (DES) implantation. Methods: We retrospectively assessed ACS patients with CKD who underwent successful DES implantation between January 2007 and December 2009. Patients were followed up from January to March 2012. CKD was defined as an estimated glomerular filtration rate 2. We assessed the association between SUA levels and mortality. Results: A total of 1,132 patients were included. The mean age was 67.7 years. During a mean follow-up of 38.5 months, 145 patients died: 50 from cardiac diseases, 28 from cerebral diseases, 14 from renal diseases and 53 from other causes. After adjustment for confounders, SUA levels increased the risk of all-cause, cerebral and other-cause mortality. Adjusted hazard ratios for quartiles 3 and 4 versus quartile 1 of SUA were: all-cause, 1.66 [95% confidence interval (CI) 1.08-2.78] and 1.99 (95% CI 1.21-3.23); cerebral, 2.24 (95% CI 0.43-11.7) and 5.89 (95% CI 1.30-26.6); and other causes, 2.81 (95% CI 1.17-6.78) and 3.89 (95% CI 1.63-9.29), respectively. SUA levels had no impact on cardiac and renal mortality rates. Conclusions: High SUA levels are associated with all-cause, cerebral and other-cause mortality rates in ACS patients with CKD after DES implantation. Future research is needed to determine if lowering SUA levels will decrease mortality in these patients.