Development and validation of an online dynamic nomogram system for pulmonary consolidation in children with Mycoplasma pneumoniae pneumonia.

INTRODUCTION: The occurrence of pulmonary consolidation in children with Mycoplasma pneumoniae pneumonia (MPP) can lead to exacerbation of the disease. Therefore, early identification of children with MPP in combination with pulmonary consolidation is critical. The purpose of this study was to develop a straightforward, easy-to-use online dynamic nomogram for the identification of children with MPP who are at high risk of developing pulmonary consolidation. METHODS: 491 MPP patients were chosen and divided randomly into a training cohort and an internal validation cohort at a 4:1 ratio. Multi-factor logistic regression was used to identify the risk variables for mixed pulmonary consolidation in children with Mycoplasma pneumoniae (MP). The selected variables were utilized to build the nomograms and validated using the C-index, decision curve analysis, calibration curves, and receiver operating characteristic (ROC) curves. RESULTS: Seven variables were included in the Nomogram model: age, fever duration, lymphocyte count, C-reactive protein (CRP), ferritin, T8 lymphocyte percentage, and T4 lymphocyte percentage. We created a dynamic nomogram that is accessible online ( https://ertong.shinyapps.io/DynNomapp/ ). The C-index was 0.90. The nomogram calibration curves in the training and validation cohorts were highly comparable to the standard curves. The area under the curve (AUC) of the prediction model was, respectively, 0.902 and 0.883 in the training cohort and validation cohort. The decision curve analysis (DCA) curve shows that the model has a significant clinical benefit. CONCLUSIONS: We developed a dynamic online nomogram for predicting combined pulmonary consolidation in children with MP based on 7 variables for the first time. The predictive value and clinical benefit of the nomogram model were acceptable.

Effects of Perineal Warm Compresses during the Second Stage of Labor on Reducing Perineal Trauma and Relieving Postpartum Perineal Pain in Primiparous Women: A Systematic Review and Meta-Analyses.

Non-pharmaceutical midwifery techniques, including perineal warm compresses, to improve maternal outcomes remain controversial. The aims of this study are to assess the effects of perineal warm compresses on reducing perineal trauma and postpartum perineal pain relief. This systematic review included randomized controlled trials (RCTs). We searched seven bibliographic databases, three RCT register websites, and two dissertation databases for publications from inception to 15 March 2023. Chinese and English publications were included. Two independent reviewers conducted the risk of bias assessment, data extraction, and the evaluation of the certainty of the evidence utilizing the Cochrane risk of bias 2.0 assessment criteria, the Review Manager 5.4, and the online GRADEpro tool, respectively. Seven RCTs involving 1362 primiparous women were included. The combined results demonstrated a statistically significant reduction in the second-, third- and/or fourth- degree perineal lacerations, the incidence of episiotomy, and the relief of the short-term perineal pain postpartum (within two days). There was a potential favorable effect on improving the integrity of the perineum. However, the results did not show a statistically significant supportive effect on reducing first-degree perineal lacerations and the rate of perineal lacerations requiring sutures. In summary, perineal warm compresses effectively reduced the second-, third-/or fourth-degree perineal trauma and decreased the short-term perineal pain after birth.

Value of modified qSOFA, glucose and lactate in predicting prognosis in children with sepsis in the PICU.

The purpose was to investigate how well age-adjusted modified quick Sequential Organ Failure Assessment (qSOFA) scores paired with blood glucose and lactate levels predict the outcomes of septicemic children in the pediatric intensive care unit (PICU). One hundred children who were diagnosed with sepsis and septic shock in the PICU of Henan Children's Hospital were eligible, and other 20 patients in the same hospital at different times were selected as a validation set. Respiratory rate (RR), heart rate (HR), capillary refill time (CRT), and Alert, Voice, Pain, Unresponsive (AVPU) scale were included in the age-adjusted modified qSOFA scoring criteria for scoring. The primary outcome was 28-day all-cause mortality. The predictive values were evaluated by the ROC curve. In the sepsis group, 50 patients were male, and 50 patients were female. The 28-day all-cause mortality rate was 52%. Fifty-one patients with age-adjusted modified qSOFA scores >1. The serum lactate level was 2.4 mmol/L, and the blood glucose level was 9.3 mmol/L. The AUCs for the age-adjusted modified qSOFA score, serum lactate and blood glucose levels for the prediction of 28-day all-cause mortality in children with sepsis were 0.719, 0.719 and 0.737, respectively. The cut-off values were one point, 3.8 mmol/L and 10 mmol/L, respectively. The AUC of the age-adjusted modified qSOFA score for the validation set of was 0.925. When the three indices were combined, the AUC was 0.817, the Hosmer-Lemeshow goodness-of-fit test showed χ2 = 2.428 and p = .965. When children with sepsis are admitted to the ICU, we recommend performing rapid scoring and rapid bedside lactate and glucose testing to determine the early prognosis.

Impact of the COVID-19 outbreak and interventions on hand, foot and mouth disease in Zhengzhou, China, 2014-2022: a retrospective study.

BACKGROUND: Since December 2019, COVID-19 has spread rapidly around the world, and studies have shown that measures to prevent COVID-19 can largely reduce the spread of other infectious diseases. This study explored the impact of the COVID-19 outbreak and interventions on the incidence of HFMD. METHODS: We gathered data on the prevalence of HFMD from the Children's Hospital Affiliated to Zhengzhou University. An autoregressive integrated moving average model was constructed using HFMD incidence data from 2014 to 2019, the number of cases predicted from 2020 to 2022 was predicted, and the predicted values were compared with the actual measurements. RESULTS: From January 2014 to October 2022, the Children's Hospital of Zhengzhou University admitted 103,995 children with HFMD. The average number of cases of HFMD from 2020 to 2022 was 4,946, a significant decrease from 14,859 cases from 2014 to 2019. We confirmed the best ARIMA (2,0,0) (1,1,0)12 model. From 2020 to 2022, the yearly number of cases decreased by 46.58%, 75.54%, and 66.16%, respectively, compared with the forecasted incidence. Trends in incidence across sexes and ages displayed patterns similar to those overall. CONCLUSIONS: The COVID-19 outbreak and interventions reduced the incidence of HFMD compared to that before the outbreak. Strengthening public health interventions remains a priority in the prevention of HFMD.

A new dynamic nomogram for predicting the risk of severe Mycoplasma pneumoniae pneumonia in children.

Mycoplasma pneumoniae pneumonia (MPP) is usually mild and self-limiting, but still about 12% of them will progress to severe Mycoplasma pneumoniae pneumonia (SMPP), which have poor survival rates and often require intensive medical resource utilization. We retrospectively collected clinical data from 526 children with MPP admitted to the Children's Hospital Affiliated to Zhengzhou University from June 2018 to February 2023 and randomly divided the data into a training cohort and a validation cohort at a ratio of 4:1. Univariate and multivariate logistic regressions were used to identify independent risk factors for SMPP. Age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze are independent risk factors for SMPP in children. Then, we built an online dynamic nomogram ( https://ertongyiyuanliexiantu.shinyapps.io/SMPP/ ) based on the 11 independent risk factors. The C-index, ROC curve, DCA curve and calibration curve were used to assess the performance of the nomogram, which all showed that the dynamic nomogram has excellent clinical value. Based on age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze, the first dynamic nomogram for accurately predicting SMPP was successfully established.

Research on 3D point cloud alignment algorithm based on SHOT features.

To overcome the problem of the high initial position of the point cloud required by the traditional Iterative Closest Point (ICP) algorithm, in this paper, we propose a point cloud registration method based on normal vector and directional histogram features (SHOT). Firstly, a hybrid filtering method based on the voxel idea is proposed and verified using the measured point cloud data, and the noise removal rates of 97.5%, 97.8%, and 93.8% are obtained. Secondly, in terms of feature point extraction, the original algorithm is optimized, and the optimized algorithm can better extract the missing part of the point cloud. Finally, a fine alignment method based on normal vector and directional histogram features (SHOT) is proposed, and the improved algorithm is compared with the existing algorithm. Taking the Stanford University point cloud data and the self-measured point cloud data as examples, the plotted iteration-error plots can be concluded that the improved method can reduce the number of iterations by 40.23% and 37.62%, respectively.

Clinical Characteristics of Lung Consolidation with Mycoplasma pneumoniae Pneumonia and Risk Factors for Mycoplasma pneumoniae Necrotizing Pneumonia in Children.

INTRODUCTION: Mycoplasma pneumoniae necrotizing pneumonia (MPNP) is an uncommon but increasingly recognized severe complication of pneumonia, and the delayed diagnosis and treatment are prone to pulmonary sequelae. The aim of this study is to explore independent risk factors for MPNP in children with lung consolidation. METHODS: A retrospective observational study was conducted on 118 children with MPNP (MPNP group) and 184 children with lung consolidation of Mycoplasma pneumoniae pneumonia (MPP) (control group) admitted to Children's Hospital Affiliated to Zhengzhou University from June 2018 to August 2023. Clinical manifestations and laboratory data were analyzed and the independent risk factors for MPNP in children were analyzed by multivariate logistic regression. RESULTS: The age of onset, hospitalization days, fever days, proportion of dyspnea, chest pain, complications, and need for fiberoptic bronchoscopic alveolar lavage (FBAL) were higher than those in the control group, and the difference was statistically significant (P < 0.05). The levels of white blood cells (WBC), platelets, neutrophil percentage (N%), neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), fibrinogen (Fbg), D-dimer (D-D), erythrocyte sedimentation rate (ESR), alanine transaminase (ALT), γ-glutamyl transpeptidase (γ-GGT), globulin, lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (α-HBDH), urea, immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin A (IgA), complement component 3, antistreptolysin O (ASO), serum ferritin, and interleukin-6 (IL-6) in the MPNP group were higher than those in the control group. Red blood cell (RBC), lymphocyte percentage (L%), activated partial thromboplastin time (APTT), alkaline phosphatase (ALP), total protein, albumin, albumin-to-globulin ratio (AGR), creatine kinase (CK), uric acid, natrium, chlorine, calcium, and complement C4 in the MPNP group were lower than those in the control group, and the difference was statistically significant (P < 0.05). The results of multivariate logistic regression analysis showed that age ≥ 83.50 months, fever days ≥ 10.50, ALT ≥ 15.25 U/l, IgM ≥ 1.46 g/l, complement C3 ≥ 1.47 g/l, Fbg ≥ 3.93 g/l, dyspnea and needing FBAL were independent risk factors for MPNP in children. CONCLUSIONS: Age, fever days, ALT, IgM, complement C3, Fbg, dyspnea, and needing FBAL were independent risk factors for MPNP in children. For children suspected of MPNP, pediatricians should pay close attention to the above indicators, strive for early diagnosis and treatment, and improve prognosis.

Analysis of clinical characteristics and risk factors for death due to severe influenza in children.

OBJECTIVE: The study analyzed the clinical features of children who had severe influenza and discussed on the risk factors associated with death in this population. METHODS: A total of 167 children with severe influenza admitted to the intensive care unit of our hospital from January 2018 to August 2023 were selected and divided into the death group (27 cases) and the survival group (140 cases). Demographic characteristics and clinical data were collected and compared between the two groups. Logistic regression analysis was used to explore the risk factors for death in children with severe influenza. RESULTS: The male-to-female ratio of the 167 children with severe influenza was 2.21:1, the median age was 3 years, and influenza A accounted for 70.66%. The CD4+ T cells percentage and CD4/CD8 were lower in the death group; the percentage of comorbid underlying diseases, mechanical ventilation, other systemic involvement, comorbid associated encephalopathy or encephalitis, and red blood cell distribution width (RDW), lactate dehydrogenase, activated partial thromboplastin time (APTT), and interleukin 6 were higher in the death group. The mechanical ventilation, associated encephalopathy or encephalitis, RDW, APTT, and CD4/CD8 were the independent risk factors for death. CONCLUSION: Mechanical ventilation, comorbid encephalopathy or encephalitis, increased RDW, prolonged APTT, and decreased CD4/CD8 are independent risk factors for death in children with severe influenza.

Effective measures to improve influenza vaccination coverage among healthcare workers during and after COVID-19.

The influenza vaccine is the most effective measure to prevent influenza. The aim of this study was to evaluate the impact of measures taken by the hospital on the influenza vaccination coverage of medical staff after implementation. We collected and compared the influenza vaccination of staff in key departments from 2018 to 2022. As the results, in 2018 and 2019, the influenza vaccination rates of staff in key departments in our hospital were generally as low as 10.3% and 11.6%, respectively. After the policy of free vaccination for staff in key departments was adopted in 2020 and other incentive measures, the overall influenza vaccination rates of key departments from 2020 to 2022 were 77.2%, 71.4%, and 81.3%, respectively, which were significantly higher than the pre-2020 vaccination rates in our hospital and healthcare workers in most regions of China. In conclusion, with the implementation of several measures to promote influenza vaccination, the rate of influenza vaccination among medical staff has significantly increased.

Development of an Efficient On-Tissue Epoxidation Reaction Mediated by Urea Hydrogen Peroxide for MALDI MS/MS Imaging of Lipid C═C Location Isomers.

Unsaturated lipids containing different numbers and locations of C═C bonds are significantly associated with a variety of cellular and metabolic functions. Although matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) has been used to visualize the spatial distribution patterns of various lipids in biological tissues, in situ identification, discrimination, and visualization of lipid C═C location isomers remain challenging. Herein, an efficient and fast on-tissue chemical derivatization (OTCD) approach was developed to pinpoint the locations of C═C bonds in complex lipids in situ via methyltrioxorhenium (MTO)-catalyzed epoxidation of C═C with a urea hydrogen peroxide (UHP)/hexafluoroisopropanol (HFIP) system. The efficiency of OTCD could reach 100% via one-step spray deposition of the solution mixture of MTO/UHP/HFIP at room temperature. The developed OTCD method provided rich structural information on lipid C═C location isomers, and their accurate spatial distribution patterns were resolved in mouse brain tissues. Tissue-specific distributions and changes of lipid C═C location isomers in the liver sections of obese ob/ob and diabetic db/db mice were further investigated, and their correlation in two animal models was revealed. The simplicity and high efficiency of the OTCD method developed for MALDI tandem MSI of lipid C═C location isomers possess great potential for functional spatial lipidomics.

Formation of oil-particle aggregates in the presence of marine algae.

After an oil spill, the formation of oil-particle aggregates (OPAs) is associated with the interaction between dispersed oil and marine particulate matter such as phytoplankton, bacteria and mineral particles. Until recently, the combined effect of minerals and marine algae in influencing oil dispersion and OPA formation has rarely been investigated in detail. In this paper, the impacts of a species of flagellate algae Heterosigma akashiwo on oil dispersion and aggregation with montmorillonite were investigated. This study has found that oil coalescence is inhibited due to the adhesion of algal cells on the droplet surface, causing fewer large droplets to be dispersed into the water column and small OPAs to form. Due to the role of biosurfactants in the algae and the inhibition of algae on the swelling of mineral particles, both the oil dispersion efficiency and oil sinking efficiency were improved, which reached 77.6% and 23.5%, respectively at an algal cell concentration (Ca) of 1.0 × 106 cells per mL and a mineral concentration of 300 mg L-1. The volumetric mean diameter of the OPAs decreased from 38.4 µm to 31.5 µm when Ca increased from 0 to 1.0 × 106 cells per mL. At higher turbulent energy, more oil tended to form larger OPAs. The findings may add knowledge about the fate and transport of spilled oil and provide fundamental data for oil spill migration modelling.

Detection of Advanced Glycosylation End Products in the Cornea Based on Molecular Fluorescence and Machine Learning.

Advanced glycosylation end products (AGEs) are continuously produced and accumulated in the bodies of diabetic patients. To effectively predict disease trends in diabetic patients, a corneal fluorescence detection device was designed based on the autofluorescence properties of AGEs, and corneal fluorescence measurements were performed on 83 volunteers. Multiple linear regression (MLR), extreme gradient boosting (XGBoost), support vector regression (SVR), and back-propagation neural network (BPNN) were used to predict the human AGE content. Physiological parameters which may affect corneal AGE content were collected for a correlation analysis to select the features that had a strong correlation with the corneal concentration of AGEs to participate in modeling. By comparing the predictive effects of the four models in the two cases of a single-input feature and a multi-input feature, it was found that the model with the single-input feature had a better predictive effect. In this case, corneal AGE content was predicted by a single-input SVR model, with the average error rate (AER), mean square error (MSE), and determination coefficient R-squared (R2) of the SVR model calculated as 2.43%, 0.026, and 0.932, respectively. These results proved the potential of our method and device for noninvasive detection of the concentration of AGEs in the cornea.

Anthropogenic activity and millennial climate variability affect Holocene mercury deposition of an alpine wetland near the largest mercury mine in China.

Mercury (Hg) is a potentially toxic element that can be transported globally through the atmosphere, once deposited in the environment, has strong bioaccumulation and extreme toxicity in food webs, especially in wetland ecosystems. Anthropogenic Hg emissions have enhanced Hg deposition by 3-5 times since the industrial revolution, and the mining and smelting of Hg ore are important emission sources. However, the dynamics in Hg deposition around the largest Hg mine in China before the industrial revolution and their driving forces remain poorly explored. Here we reconstruct the atmospheric Hg depositional fluxes (named here Hg influx (Hginflux)) during the Holocene using a 450-cm alpine wetland sediment core taken from the Jiulongchi wetland, which is only 65 km to the Wanshan Mercury Mine. Our record shows an abrupt rapid increase in Hg concentration since 2500 cal yr BP, suggesting that Hg mining in southwest China may have started before the establishment of the Qin dynasty. Two major Hginflux peaks were found during the periods 10,000-6000 and 6000 - 3800 cal yr BP, with an increase in Hg deposition by a factor of 4-8. These two peaks are also found in other terrestrial archives from several sites across the Northern Hemisphere. We speculate that critical millennial-scale climate changes, i.e., the Holocene Climatic Optimum (HCO) and the Mid-Holocene Transition (MHT), were the potential triggers of these two Hginflux peaks. This study highlights the importance of climatic variability and local Hg mining in controlling atmospheric Hg deposition during the Holocene.

Effects of perineal massage during childbirth on maternal and neonatal outcomes in primiparous women: A systematic review and meta-analysis.

BACKGROUND: Perineal massage during childbirth has been recommended as an effective measure to prevent perineal injury. However, the overall effects of perineal massage during childbirth on maternal and neonatal outcomes in primiparous women remain inconclusive. Particularly, the effects of perineal massage begun during different stages of labor need to be further investigated. OBJECTIVES: To comprehensively review the effects of perineal massage during childbirth on primiparous health outcomes, including perineal-related outcomes, duration of labor, hemorrhage and postpartum perineal pain, and neonatal outcomes, including Apgar scores and neonatal complications, and to further explore the effects of perineal massage begun during different stages of labor. DESIGN: A systematic review and meta-analysis following the Cochrane Handbook guidelines and PRISMA2020. METHODS: A systematic search strategy was developed following the three-phase search approach, and the literature search was conducted in electronic databases and clinical trial registers from inception to 7th January 2022. Study selection and data extraction were completed independently by two researchers. The updated Cochrane risk of bias 2.0 tool for randomized trials was chosen to evaluate the quality of included studies. Data analyses were conducted using the Revman5.4 software, and subgroup analyses were performed based on the different start times of perineal massage. Furthermore, the certainty of body of evidence for each outcome was assessed utilizing the GRADEpro online tool. RESULTS: Seventeen randomized controlled trials involving 3248 primiparous women were included in the review. The pooled results of meta-analyses indicated that perineal massage begun during the second stage of labor significantly increased the occurrence of intact perineum (RR = 2.78, 95 % CI: [1.52, 5.05], P < 0.001), reduced the rate of second- and third-degree perineal lacerations (P < 0.05), and decreased the incidence of episiotomy (RR = 0.63, 95 % CI: [0.50, 0.79], P < 0.001), while perineal massage during the first stage of labor effectively shortened the duration of the first and second stages of labor (P < 0.05). The available evidence also suggests the potential role of perineal massage on hemorrhage and long-term postpartum perineal pain (P < 0.05). However, the aggregated results failed to demonstrate the beneficial effects of perineal massage on neonatal outcomes (P > 0.05). CONCLUSIONS: Perineal massage begun during the second stage of labor effectively improves the perineal-related outcomes in primiparous women, while perineal massage during the first stage of labor significantly shortens the duration of labor. High-quality studies exploring the standardized procedure for perineal massage and the short- and long-term effects of perineal massage are warranted. REGISTRATION NUMBER: CRD42022302336 (PROSPERO).

A Non-Invasive Hemoglobin Detection Device Based on Multispectral Photoplethysmography.

The measurement of hemoglobin is a vital index for diagnosing and monitoring diseases in clinical practice. At present, solutions need to be found for the soreness, high risk of infection, and inconvenient operation associated with invasive detection methods. This paper proposes a method for non-invasively detecting hemoglobin levels based on multi-wavelength photoplethysmography (PPG) signals. AFE4490 and TMUX1109 were used to implement the low-cost collection of an eight-LED transmissive PPG signal. We used seven regular LEDs and one broadband LED (Osram SFH4737) as light sources. Additionally, a finger clip integrating multiple sensors was designed and manufactured via 3D printing to simultaneously monitor the LED-sensor distance and the pressure from the tester's finger during PPG signal acquisition. We used a method to extract features from PPG signals using a sliding-window's variance and an evaluation metric for PPG signals based on the AdaCost classification. Data were gathered from 56 participants from the Nephrology department, including 16 anemic patients. Pearson correlation analysis was conducted on the collected data to remove any data with a weak correlation. The advantage of using a broadband LED as a light source was also demonstrated. Several non-invasive hemoglobin regression models were created by applying AdaBoost, BPNN, and Random Forest models. The study's results indicate that the AdaBoost model produced the best performance, with a mean absolute error (MAE) of 2.67 g/L and a correlation coefficient (R2) of 0.91 The study results show that the device we designed and manufactured can achieve effective non-invasive hemoglobin detection and represents a new methodological approach to obtaining measurements that can be applied in a clinical setting.

Free-Form Surface Partitioning and Simulation Verification Based on Surface Curvature.

To address the problem of low overall machining efficiency of free-form surfaces and difficulty in ensuring machining quality, this paper proposes a MATLAB-based free-form surface division method. The surface division is divided into two stages: Partition area identification and area boundary determination. In the first stage, the free-form surface is roughly divided into convex, concave, and saddle regions according to the curvature of the surface, and then the regions are subdivided based on the fuzzy c-means clustering algorithm. In the second stage, according to the clustering results, the Voronoi diagram algorithm is used to finally determine the boundary of the surface patch. We used NURBS to describe free-form surfaces and edit a set of MATLAB programs to realize the division of surfaces. The proposed method can easily and quickly divide the surface area, and the simulation results show that the proposed method can shorten machining time by 36% compared with the traditional machining method. It is proved that the method is practical and can effectively improve the machining efficiency and quality of complex surfaces.

Submicron 3,4-dihydroxybenzoic acid-TiO2 composite particles for enhanced MALDI MS imaging of secondary metabolites in the root of differently aged baical skullcap.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has become an attractive technique for the localization and visualization of small molecules in various biological tissue sections. In this work, submicron 3,4-dihydroxybenzoic acid-TiO2 composite particles (3,4-DHB-TiO2 CPs) were synthesized for enhanced MALDI MSI of secondary metabolites in the root of Scutellaria baicalensis Georgi (baical skullcap). Submicron TiO2 particles were synthesized as starting materials by using a facile sol-gel method and chemically modified with six analogs of dihydroxybenzoic acids (DHB) (2,3-DHB, 2,4-DHB, 2,5-DHB, 2,6-DHB, 3,4-DHB, and 3,5-DHB). Among them, 3,4-DHB-TiO2 CPs provided superior performance in MALDI MSI of small molecules. Compared with conventional matrices, such as 2,5-dihydroxybenzoic acid (2,5-DHB) and α-cyano-4-hydroxycinnamic acid (CHCA), 3,4-DHB-TiO2 CPs exhibited low background noise and high detection sensitivity for the visualization of spatial distribution patterns of secondary metabolites in the roots of differently aged S. baicalensis by using MALDI MSI. The age-related spatial and content changes of flavonoids in S. baicalensis roots were demonstrated and further validated by liquid chromatography-mass spectrometry (LC-MS). This work provides a potential organic-inorganic hybrid matrix for MALDI MSI of secondary metabolites in plant tissues.

Experimental investigations on the vertical distribution and properties of oil-mineral aggregates (OMAs) formed by different clay minerals.

After oil spills, the floating oil may interact with suspended minerals to form the oil-mineral aggregates (OMAs) in turbulent environments. In this work, a flume was used in conjunction with a settling device to investigate the vertical distribution and properties of OMAs formed by different clay minerals. The density and size of OMAs depend on the density and surface properties of the constituent particles, which also affect the vertical distribution of dispersed oil. Density of oil-montmorillonite aggregates increased from 1165 to 1897 kg/m3 within 6 h test. Among the four minerals, montmorillonite displayed the highest affinity with dispersed oil and the most significant modification of oil-water interfacial tension. Oil dispersion efficiency was significantly greater and reached 39.3% in the presence of montmorillonite at 300 mg/L compared with the control group (17.6%). Particle concentration is the most important factor for the capture of oil and participation of particles during the OMA formation, while the zeta potential and hydrophobicity have nonsignificant effect on the two processes. Cation exchange capacity has a moderate effect on the sunken oil formation, which is also the second main factor governing the particle participation. Particle size plays a second leading role in governing the sunken oil formation but with a minor contribution of the particle participation.

Obstacle Capability of an Air-Ground Amphibious Reconnaissance Robot with a Planetary Wheel-Leg Type Structure.

According to the requirements of the reconnaissance robot for the ability to adapt to a complex environment and the in-depth study of the obstacle climbing mechanisms, a planetary wheel-leg-combined mechanism capable of adapting to complex terrains is proposed. According to the proposed planetary wheel-leg-combined mechanism, the land part of the air-ground amphibious reconnaissance robot is designed. Considering the obstacle and fast marching performance, four groups of combined wheel-leg mechanisms are adopted in the land bank. Under the action of three kinds of obstacles, the stability and the movement ability of the robot are analyzed by using the static method. The parameter model of the reconnaissance robot is built by a virtual prototype dynamics software MSC.ADMAS. The kinematic characteristic curves of each component and the whole prototype are obtained, which provides a theoretical basis for the design and numerical calculation of the robot structure. Finally, the climbing ability tests of the reconnaissance robot prototype verify the reliability and practicability of the body structure of the reconnaissance robot.

Performance of dispersed oil and suspended sediment during the oil-sediment aggregation process.

Oil-sediment aggregation is an important transport and transformation process of spilled oil, which has been considered as a pathway of spill remediation. This work focused on the individual performance of dispersed oil and sediment during the aggregation process. Dispersion of three oils was first tested and validated in a water tank. An approach of estimating the mass variation of the sediment that has participated in forming the oil-sediment aggregates (OSAs) has been developed by density analysis. Results indicated that the density of the formed OSAs increases during the aggregation. In the context of remediation, it takes longer for sediment to reach equilibrium than for dispersed oil, especially under high mixing energy at a large sediment concentration, which results in the formation of dense OSAs, as well as high aggregation degree and rate. Roncador oil possesses a relatively high capability of capturing sediment to form dense OSAs, especially at an initial sediment concentration of over 150 mg/L. Oil sinking efficiency and the characteristic change rate of aggregated oil mass seem to be proportional to oil dispersion efficiency, and decrease with the mean size of dispersed oil droplets. The process of aggregation can further promote the dispersion of oil into water column. This study also provides fundamental data for the formation kinetics of OSAs.