Publications by authors named "Guangming Zheng"

11 Publications

  • Page 1 of 1

Clinical Evaluation a New Treatment for Infection After Ventriculoperitoneal Shunt.

J Craniofac Surg 2021 Jan-Feb 01;32(1):e46-e49

Department of Neurosurgery, Kaifeng Central Hospital, Kaifeng, China.

Abstract: To explore a new surgical treatment for infection and obstruction of ventriculoperitoneal shunt in hydrocephalus. Two cases of post-operative infection of ventriculoperitoneal shunt were analyzed retrospectively. One case was cryptococcal infection, the other case was Acinetobacter lwoffii. The number of cerebrospinal fluid cells was high, the infection of ventriculoperitoneal shunt was generally complicated with abdominal obstruction, and the hydrocephalus was aggravated again, The authors try to pull out the drainage tube at the end of abdominal cavity for external drainage, combined with intravenous antibiotics, completely control of infection, and then use the original shunt device for intraventricular jugular shunt. The authors explore that this method is simple, safe and effective, and it is an effective and feasible method for the treatment of infection after ventriculoperitoneal shunt.
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http://dx.doi.org/10.1097/SCS.0000000000006975DOI Listing
November 2020

Model for Predicting the Micro-Grinding Force of K9 Glass Based on Material Removal Mechanisms.

Micromachines (Basel) 2020 Oct 29;11(11). Epub 2020 Oct 29.

School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China.

K9 optical glass has superb material properties used for various industrial applications. However, the high hardness and low fracture toughness greatly fluctuate the cutting force generated during the grinding process, which are the main factors affecting machining accuracy and surface integrity. With a view to further understand the grinding mechanism of K9 glass and improve the machining quality, a new arithmetical force model and parameter optimization for grinding the K9 glass are introduced in this study. Originally, the grinding force components and the grinding path were analyzed according to the critical depth of plowing, rubbing, and brittle tear. Thereafter, the arithmetical model of grinding force was established based on the geometrical model of a single abrasive grain, taking into account the random distribution of grinding grains, and this fact was considered when establishing the number of active grains participating in cutting N. It should be noted that the tool diameter changed with machining, therefore this change was taking into account when building the arithmetical force model during processing as well as the variable value of the maximum chip thickness a accordingly. Besides, the force analysis recommends how to control the processing parameters to achieve high surface and subsurface quality. Finally, the force model was evaluated by comparing theoretical results with experimental ones. The experimental values of surface grinding forces are in good conformity with the predicted results with changes in the grinding parameters, which proves that the mathematical model is reliable.
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http://dx.doi.org/10.3390/mi11110969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693084PMC
October 2020

Simulation Analysis of the Influence of Nozzle Structure Parameters on Material Controllability.

Micromachines (Basel) 2020 Aug 31;11(9). Epub 2020 Aug 31.

School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China.

With the evolution of three-dimensional (3D) printing, many restrictive factors of 3D printing have been explored to upgrade the feasibility of 3D printing technology, such as nozzle structure, print resolution, cell viability, etc., which has attracted extensive attention due to its possibility of curing disease in tissue engineering and organ regeneration. In this paper, we have developed a novel nozzle for 3D printing, numerical simulation, and finite element analysis have been used to optimize the nozzle structure and further clarified the influence of nozzle structure parameters on material controllability. Using novel nozzle structure, we firstly adopt ANSYS-FLUENT to analyze material controllability under the different inner cavity diameter, outer cavity diameter and lead length. Secondly, the orthogonal experiments with the novel nozzle are carried out in order to verify the influence law of inner cavity diameter, outer cavity diameter, and lead length under all sorts of conditions. The experiment results show that the material diameter can be controlled by changing the parameters. The influence degree of parameters on material diameter is shown that lead length > inner cavity diameter > outer cavity diameter. Finally, the optimized parameters of nozzle structure have been adjusted to estimate the material diameter in 3D printing.
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http://dx.doi.org/10.3390/mi11090826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570424PMC
August 2020

Fractal Characteristics of Chip Morphology and Tool Wear in High-Speed Turning of Iron-Based Super Alloy.

Materials (Basel) 2020 Feb 24;13(4). Epub 2020 Feb 24.

School of Mechanical Engineering, Shandong University of Technology, 266 West Xincun Road, Zibo 255000, China.

Considering that iron-based super alloy is a kind of difficult-to-cut material, it is easy to produce work hardening and serious tool wear during machining. Therefore, this work aims to explore the chip change characteristics and tool wear mechanism during the processing of iron-based super alloy, calculate the fractal dimensions of chip morphology and tool wear morphology, and use fractals to analyze their change trend. Meanwhile, a new cutting tool with a super ZX coating is used for a high-speed dry turning experiment. The results indicate that the morphology of the chip is saw-tooth, and its color changes gradually, due to the oxidation reaction. The main wear mechanisms of the tool involve abrasive wear, adhesive wear, oxidation wear, coating spalling, microcracking and chipping. The fractal dimension of the tool wear surface and chip is increased with the improvement of cutting speed. This work investigates the fractal characteristics of chip morphology and tool wear morphology. The fractal dimension changes regularly with the change of tool wear, which plays an important role in predicting this tool wear. It is also provides some guidance for the efficient processing of an iron-based super alloy.
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http://dx.doi.org/10.3390/ma13041020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079632PMC
February 2020

Cutting Performance Evaluation of the Coated Tools in High-Speed Milling of AISI 4340 Steel.

Materials (Basel) 2019 Oct 7;12(19). Epub 2019 Oct 7.

School of Mechanical Engineering, Shandong University of Technology; 266 West Xincun Road, Zibo 255000, China.

The cutting performance of cutting tools in high-speed machining (HSM) is an important factor restricting the machined surface integrity of the workpiece. The HSM of AISI 4340 is carried out by using coated tools with TiN/TiCN/TiAlN multi-coating, TiAlN + TiN coating, TiCN + NbC coating, and AlTiN coating, respectively. The cutting performance evaluation of the coated tools is revealed by the chip morphology, cutting force, cutting temperature, and tool wear. The results show that the serration and shear slip of the chips become more clear with the cutting speed. The lower cutting force and cutting temperature are achieved by the TiN/TiCN/TiAlN multi-coated tool. The flank wear was the dominant wear form in the milling process of AISI 4340. The dominant wear mechanisms of the coated tools include the crater wear, coating chipping, adhesion, abrasion, and diffusion. In general, a TiN/TiCN/TiAlN multi-coated tool is the most suitable tool for high-speed milling of AISI 4340, due to the lower cutting force, the lower cutting temperature, and the high resistance of the element diffusion.
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http://dx.doi.org/10.3390/ma12193266DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6804202PMC
October 2019

Pharmacokinetics and tissue residues of enrofloxacin in the largemouth bass (Micropterus salmoides) after oral administration.

J Vet Pharmacol Ther 2020 Mar 20;43(2):147-152. Epub 2019 Jul 20.

Key Laboratory of Recreational Fisheries Research, Ministry of Agriculture and Ministry of Agriculture Laboratory of Quality & Safety Risky Assessment for Aquatic Product, Pearl River Fisheries Research Institute, Chinese Academic of Fishery Science, Guangzhou, China.

The study was carried out to evaluate the pharmacokinetic disposition of enrofloxacin (ENF) with a single dose of 20 mg/kg after oral administration in largemouth bass (Micropterus salmoides) at 28°C. The concentrations of ENF and of its metabolite ciprofloxacin (CIP) in plasma, liver, and muscle plus skin in natural proportions were determined using HPLC. The concentration-time data for ENF in plasma were best described by a two-compartment open model. After oral administration, the maximum ENF concentration (C ) of 10.99 μg/ml was obtained at 0.60 hr. The absorption half-life (T ) of ENF was calculated to be 0.07 hr whereas the elimination half-life (T ) of the drug was 90.79 hr. The estimates of area under the plasma concentration-time curve (AUC) and apparent volume of distribution (Vd/F) were 1,185.73 μg hr/ml and 2.21 L/kg, respectively. ENF residues were slowly depleted from the liver and muscle plus skin of largemouth bass with the T of 124.73 and 115.14 hr, respectively. Very low levels of ciprofloxacin were detected in the plasma and tissues. A withdrawal time of 24 days was necessary to ensure that the residues of ENF + CIP in muscle plus skin were less than the maximal residue limit (MRL) of 100 μg/kg established by the European Union.
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http://dx.doi.org/10.1111/jvp.12794DOI Listing
March 2020

Pharmacokinetic/pharmacodynamic relationship of enrofloxacin against Aeromonas hydrophila in crucian carp (Carassius auratus gibelio).

J Vet Pharmacol Ther 2018 Dec 25;41(6):887-893. Epub 2018 Jun 25.

Key Laboratory of Recreational Fisheries Research, Ministry of Agriculture and Ministry of Agriculture Laboratory of Quality & Safety Risky Assessment for Aquatic Product, Pearl River Fisheries Research Institute, Chinese Academic of Fishery Science, Guangzhou, China.

The pharmacokinetic (PK) properties of enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP) were investigated in crucian carp following oral administration at different dose levels (5, 10, 20, 40 mg/kg body weight). The disposition kinetics of ENR was found to be linear over the dose range studied. Serum half-lives ranged from 64.56 to 72.68 hr. The in vitro and ex vivo activities of ENR in serum against a pathogenic strain of Aeromonas hydrophila were determined. In vitro and ex vivo bactericidal activity of ENR was concentration dependent. Dosing of 10 mg/kg resulted in an AUC/minimum inhibitory concentration (MIC) ratio of 368.92 hr and a C /MIC ratio of 7.23, respectively, against A. hydrophila 147 (MIC = 0.48 μg/ml), indicating a likely high level of effectiveness in clinical infections caused by A. hydrophila with MIC value ≤ 0.48 μg/ml. Modeling of ex vivo growth inhibition data to the sigmoid Emax equation provided the values of AUC /MIC required to produce bacteriostasis, bactericidal activity, and elimination of bacteria, these values were 21.70, 53.01, and 125.21 hr, respectively. These findings in conjunction with MIC data suggested that ENR at the dose of 7.81 mg/kg predicted a positive clinical outcome and minimize the risk of emergence of resistance.
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http://dx.doi.org/10.1111/jvp.12678DOI Listing
December 2018

Investigation of the interaction between the fate of antibiotics in aquafarms and their level in the environment.

J Environ Manage 2018 Feb 24;207:219-229. Epub 2017 Nov 24.

Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China; State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.

China is the largest freshwater aquaculture producer and antibiotics consumer in the world, and rivers in China are generally polluted by antibiotics. However, there is little information available regarding the linkage of antibiotics in aquaculture and the aquatic environment. Therefore, this study investigated the fate of antibiotics in several open water culture-based freshwater aquafarms, including integrated livestock/fish systems and non-integrated fish ponds, and explored the contamination profiles of antibiotics in the Beijiang River. Then the study tried to clarify the two-way interaction of antibiotics in aquaculture and the environment. The results showed that, when compared with the effluent from livestock farms and wastewater treatment plants, the contribution of antibiotics from non-integrated fish pond water without livestock sewage input was limited, while that of effluent from the integrated livestock/fish system was quite high. The total concentrations of antibiotics detected in the aquafarm source water were similar to those in the upper river water and generally higher than those in the corresponding fish pond water, implying that the occurrence of antibiotics in intensive aquafarms can mainly be attributed to the antibiotic residues in nearby river water. Overall, the results underscore the need to develop a sewage infrastructure for the treatment of effluent from integrated livestock/fish aquafarms, and suggest that open water culture-based fish farms should be located far from seriously contaminated sections of rivers.
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http://dx.doi.org/10.1016/j.jenvman.2017.11.030DOI Listing
February 2018

Analysis of azole fungicides in fish muscle tissues: Multi-factor optimization and application to environmental samples.

J Hazard Mater 2017 Feb 9;324(Pt B):535-543. Epub 2016 Nov 9.

State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR, China.

Azole fungicides have been reported to be accumulated in fish tissue. In this study, a sensitive and robust method using high-performance liquid chromatography-tandem mass spectrometry combined with ultrasonic extraction, solid-liquid clean-up, liquid-liquid extraction and solid-phase extraction (SPE) for enrichment and purification have been proposed for determination of azole fungicides in fish muscle samples. According to the results of non-statistical analysis and statistical analysis, ethyl acetate, primary secondary amine (PSA) and mixed-mode cation exchange cartridge (MCX) were confirmed as the best extraction solvent, clean-up sorbent and SPE cartridge, respectively. The satisfied recoveries (81.7-104%) and matrix effects (-6.34-7.16%), both corrected by internal standards, were performed in various species of fish muscle matrices. Method quantification limits of all azoles were in the range of 0.07-2.83ng/g. This optimized method was successfully applied for determination of the target analytes in muscle samples of field fish from Beijiang River and its tributaries. Three azole fungicides including climbazole, clotrimazole and carbendazim were detected at ppb levels in fish muscle tissues. Therefore, this analytical method is practical and suitable for further clarifying the contamination profiles of azole fungicides in wild fish species.
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http://dx.doi.org/10.1016/j.jhazmat.2016.11.024DOI Listing
February 2017

Correction of pathlength amplification in the filter-pad technique for measurements of particulate absorption coefficient in the visible spectral region.

Appl Opt 2015 Aug;54(22):6763-82

Spectrophotometric measurement of particulate matter retained on filters is the most common and practical method for routine determination of the spectral light absorption coefficient of aquatic particles, ap(λ), at high spectral resolution over a broad spectral range. The use of differing geometrical measurement configurations and large variations in the reported correction for pathlength amplification induced by the particle/filter matrix have hindered adoption of an established measurement protocol. We describe results of dedicated laboratory experiments with a diversity of particulate sample types to examine variation in the pathlength amplification factor for three filter measurement geometries; the filter in the transmittance configuration (T), the filter in the transmittance-reflectance configuration (T-R), and the filter placed inside an integrating sphere (IS). Relationships between optical density measured on suspensions (ODs) and filters (ODf) within the visible portion of the spectrum were evaluated for the formulation of pathlength amplification correction, with power functions providing the best functional representation of the relationship for all three geometries. Whereas the largest uncertainties occur in the T method, the IS method provided the least sample-to-sample variability and the smallest uncertainties in the relationship between ODs and ODf. For six different samples measured with 1 nm resolution within the light wavelength range from 400 to 700 nm, a median error of 7.1% is observed for predicted values of ODs using the IS method. The relationships established for the three filter-pad methods are applicable to historical and ongoing measurements; for future work, the use of the IS method is recommended whenever feasible.
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http://dx.doi.org/10.1364/AO.54.006763DOI Listing
August 2015

Evolution of sediment plumes in the Chesapeake bay and implications of climate variability.

Environ Sci Technol 2015 Jun 18;49(11):6494-503. Epub 2015 May 18.

‡Earth System Science Interdisciplinary Center, University of Maryland, 5825 University Research Court, College Park, Maryland 20740, United States.

Fluvial sediment transport impacts fisheries, marine ecosystems, and human health. In the upper Chesapeake Bay, river-induced sediment plumes are generally known as either a monotonic spatial shape or a turbidity maximum. Little is known about plume evolution in response to variation in streamflow and extreme discharge of sediment. Here we propose a typology of sediment plumes in the upper Chesapeake Bay using a 17 year time series of satellite-derived suspended sediment concentration. On the basis of estimated fluvial and wind contributions, we define an intermittent/wind-dominated type and a continuous type, the latter of which is further divided into four subtypes based on spatial features of plumes, which we refer to as Injection, Transport, Temporary Turbidity-Maximum, and Persistent Turbidity-Maximum. The four continuous types exhibit a consistent sequence of evolution within 1 week to 1 month following flood events. We also identify a "shift" in typology with increased frequency of Turbidity-Maximum types before and after Hurricane Ivan (2004), which implies that extreme events have longer-lasting effects upon estuarine suspended sediment than previously considered. These results can serve as a diagnostic tool to better predict distribution and impacts of estuarine suspended sediment in response to changes in climate and land use.
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http://dx.doi.org/10.1021/es506361pDOI Listing
June 2015