scholarly journals Physiological and Genetic Response Characteristics of Stenotrophomonas Rhizophila JC1 Under Heavy Metal Stress

2021 ◽  
Author(s):  
Shangchen Sun ◽  
Kexin Zhang ◽  
Yamiao Wu ◽  
Yonggang Wang ◽  
Jixiang Chen ◽  
...  
Keyword(s):  
Removal Rate ◽  
Cell Structure ◽  
Heavy Metal Stress ◽  
Transport Proteins ◽  
Resistant Bacteria ◽  
Long Distance ◽  
Obvious Effect ◽  
Response Characteristics ◽  
Resistance Nodulation Division ◽  
Stenotrophomonas Rhizophila

Abstract In this study, the Cu2+ (120 mg/L) and Cr6+(80 mg/L) removal rate of S. rhizophila JC1 reached at 79.9% and 89.3%, respectively. Scanning electron microscopy showed that Pb2+ and Zn2+ had no obvious effect on cell structure, but the cells became smaller and brighter under Cu2+ stress, and many nanoparticles formed on the cell surface under Cr6+ stress. The physiological response analyses demonstrated that moderate change of membrane permeability was necessary for adsorption. FI-IR and EDS analyses showed that exopolysaccharides (EPS) and the replacement of basic elements (ie., C, O) might be the main means of heavy metals adsorption by strain. In addition, 323 transport proteins were predicted in the genome of S. rhizophila JC1. Among them, two, six and five proteins of the cation diffusion facilitator, resistance-nodulation-division efflux and P-type ATPase families were respectively predicted. The expression of genes showed that the synergistic action of transport proteins played an important role in the process of adsorption. The comparative genomics analysis revealed that S. rhizophila JC1 has long-distance evolutionary relationships with other strains, but the efflux system of S. rhizophila JC1 contained the same types of metal transport proteins as other metal-resistant bacteria.

Effect of WEDM process parameters on machinability of Nimonic75 alloy using brass wire

2020 ◽  
Vol 17 (3) ◽  
pp. 389-397
Author(s):  
Harvinder Singh ◽  
Vinod Kumar ◽  
Jatinder Kapoor
Keyword(s):  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Cutting Speed ◽  
Content Type ◽  
Response Characteristics ◽  
Nickel Based Alloy ◽  
Pulse On Time ◽  
Pulse Off Time

Purpose This study aims to investigate the influence of process parameters of wire electrical discharge machining (WEDM) of Nimonic75. Nimonic75 is a Nickel-based alloy mostly used in the aerospace industry for its strength at high temperature. Design/methodology/approach One factor at a time (OFAT) approach has been used to perform the experiments. Pulse on time, pulse off time, peak current and servo voltage were chosen as input process parameters. Cutting speed, material removal rate and surface roughness (Ra) were selected as output performance characteristics. Findings Through experimental work, the effect of process parameters on the response characteristics has been found. Results identified the most important parameters to maximize the cutting speed and material removal rate and minimize Ra. Originality/value Very limited research work has been done on WEDM of Nickel-based alloy Nimonic75. Therefore, the aim of this paper to conduct preliminary experimentation for identifying the parameters, which influence the response characteristics such as material removal rate, cutting speed, Ra, etc. during WEDM of Nickel-based alloy (Nimonic75) using OFAT approach and found the machinability of Nimonic75 for further exhaustive experimentation work.

scholarly journals Effects of Concentration Variations on the Performance and Microbial Community in Microbial Fuel Cell Using Swine Wastewater

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2231 ◽  
Author(s):  
Hongjun Ni ◽  
Kaixuan Wang ◽  
Shuaishuai Lv ◽  
Xingxing Wang ◽  
Lu Zhuo ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Microbial Community ◽  
Microbial Fuel Cell ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Community Diversity ◽  
Swine Wastewater ◽  
Anode Chamber ◽  
Response Characteristics ◽  
Concentration Changes

The variation of substrate concentration in anode chamber directly affects the power generation efficiency and decontamination performance of microbial fuel cell (MFC). In this study, three concentrations of swine wastewater with 800 mg/L, 1600 mg/L and 2500 mg/L were selected as substrates, and the performance of MFC and response characteristics of anode microbial community were investigated. The results show that the concentration of a selected substrate is positively correlated with the output voltage of MFC and chemical oxygen demand (COD) removal rate. The microbial community diversity in the anode chamber and the performance of battery can be significantly affected when concentration changes in different ways, which helps to selectively cultivate the adaptable dominant bacteria to enhance the stability and decontamination performance of MFC. The community structure of anodic biofilm is mainly composed of Proteobacteria, Bacteroidetes, Firmicutes, Chloroflexi and Spirochaetae. These findings are meaningful to improve the treatment effects of swine wastewater and can help to find out the mechanism of varying concentration that influences the production of microorganisms in MFC.

scholarly journals Clinically Relevant Chromosomally Encoded Multidrug Resistance Efflux Pumps in Bacteria

2006 ◽  
Vol 19 (2) ◽  
pp. 382-402 ◽  
Author(s):  
Laura J. V. Piddock
Keyword(s):  
Antibiotic Resistance ◽  
Drug Transport ◽  
Efflux Pump ◽  
Regulatory Gene ◽  
Structural Data ◽  
Efflux Pumps ◽  
Resistant Bacteria ◽  
Multiple Drug ◽  
Transporter Gene ◽  
Resistance Nodulation Division

SUMMARY Efflux pump genes and proteins are present in both antibiotic-susceptible and antibiotic-resistant bacteria. Pumps may be specific for one substrate or may transport a range of structurally dissimilar compounds (including antibiotics of multiple classes); such pumps can be associated with multiple drug (antibiotic) resistance (MDR). However, the clinical relevance of efflux-mediated resistance is species, drug, and infection dependent. This review focuses on chromosomally encoded pumps in bacteria that cause infections in humans. Recent structural data provide valuable insights into the mechanisms of drug transport. MDR efflux pumps contribute to antibiotic resistance in bacteria in several ways: (i) inherent resistance to an entire class of agents, (ii) inherent resistance to specific agents, and (iii) resistance conferred by overexpression of an efflux pump. Enhanced efflux can be mediated by mutations in (i) the local repressor gene, (ii) a global regulatory gene, (iii) the promoter region of the transporter gene, or (iv) insertion elements upstream of the transporter gene. Some data suggest that resistance nodulation division systems are important in pathogenicity and/or survival in a particular ecological niche. Inhibitors of various efflux pump systems have been described; typically these are plant alkaloids, but as yet no product has been marketed.

Deformation Characteristics of Wood Structures under Compression

2006 ◽  
Vol 505-507 ◽  
pp. 1051-1056 ◽  
Author(s):  
Keisuke Yamaguchi ◽  
M. Otsubo ◽  
Y. Motomura ◽  
Yasuo Marumo ◽  
Hiroyuki Shiozaki ◽  
...  
Keyword(s):  
Cell Structure ◽  
Ccd Camera ◽  
Structural Features ◽  
Deformation Characteristics ◽  
Compression Process ◽  
Long Distance ◽  
Wood Structures ◽  
Process Characteristics ◽  
Compression Direction ◽  
Grain Distribution

This study is aimed at investigating the deformation characteristics and mechanisms of wood and its deformation characteristics using long distance microscope and CCD-camera. The structures of actual wood can be treated as micro cell structure and layer one. Several deformation characteristics were obtained in compression process. Characteristics of the deformation were investigated experimentally. The following results were obtained for the deformation of wood. (1) The deformation modes of cell structures and the locations where deformation is generated were clarified. (2) The characteristics of the compression of layered structures were clarified. (3) The deformation of wood was largely affected by structural features such as the grain, distribution of tree rings, and compression direction. The results obtained are useful in carrying out effective compaction of wood.

scholarly journals Molecular Characterization of Resistance-Nodulation-Division Transporters from Solvent- and Drug-Resistant Bacteria in Petroleum-Contaminated Soil

2005 ◽  
Vol 71 (1) ◽  
pp. 580-586 ◽  
Author(s):  
Norika Meguro ◽  
Yumiko Kodama ◽  
Maria-Trinidad Gallegos ◽  
Kazuya Watanabe
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Transporter Gene ◽  
Competitive Pcr ◽  
Drug Resistant Bacteria ◽  
Resistance Nodulation Division ◽  
Petroleum Contaminated Soil

ABSTRACT PCR assays for analyzing resistance-nodulation-division transporters from solvent- and drug-resistant bacteria in soil were developed. Sequence analysis of amplicons showed that the PCR successfully retrieved transporter gene fragments from soil. Most of the genes retrieved from petroleum-contaminated soils formed a cluster (cluster PCS) that was distantly related to known transporter genes. Competitive PCR showed that the abundance of PCS genes is increased in petroleum-contaminated soil.

Multi-Response Optimization of Machining Process Parameters for Wire Electrical Discharge Machining of Lead-Induced Ti-6Al-4V Alloy Using AHP–TOPSIS Method

2019 ◽  
Vol 18 (02) ◽  
pp. 213-236 ◽  
Author(s):  
A. V. S. Ram Prasad ◽  
Koona Ramji ◽  
Murahari Kolli ◽  
G. Vamsi Krishna
Keyword(s):  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Performance Characteristics ◽  
Machining Process ◽  
Analytic Hierarchy ◽  
Response Characteristics ◽  
Multi Attribute Decision Making ◽  
Pulse On Time ◽  
Pulse Off Time

In this study, the effects of the process parameters on their performance characteristics of lead-induced Ti-6Al-4V alloy were investigated. Taguchi’s [Formula: see text] orthogonal array (OA) has been used to conduct the experiments. Four process parameters were considered each at three levels. Peak current, pulse-on-time, servo voltage and pulse-off-time were selected as process parameters on performance characteristics, namely, material removal rate (MRR), surface roughness (SR) and dimensional deviation (DD). A multi-attribute decision-making (MADM) technique, namely, analytic hierarchy process (AHP) and technique for order of preference by similarity to ideal solution (TOPSIS), has been used to investigate the multiple response characteristics. The weights for performance characteristics are determined by AHP. Finally, analysis of variance method has been employed effectively to bring out the influence of the process parameters associated with each performance characteristic, namely, maximization of MRR and minimization of SR and DD.

CFD Numerical Simulation of the Submarine Pipeline With a Spoiler

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Jianping Zhao ◽  
Xuechao Wang
Keyword(s):  
Shear Stress ◽  
Hangzhou Bay ◽  
Shallow Waters ◽  
High Current ◽  
Submarine Pipeline ◽  
Dynamic Nature ◽  
Long Distance ◽  
Obvious Effect ◽  
Oil Transportation ◽  
Pipeline Failure

Submarine pipeline is one of the most important oil transportation components; pipeline failure due to overspan is the most serious failure mechanism. There are four reasons of pipeline span formation, including erosion of seabed, bumpy seabed, submarine pipeline climbing slope, and pipeline ascending to offshore platform. The Hangzhou Bay submarine pipeline is the most important subproject of the Yong-Hu-Ning network, and it is also the biggest long-distance pipeline for crude oil in China. Due to the dynamic nature of Hangzhou Bay, including high tides and high current amplified by the shallow waters, a self-burial method was selected as the best solution. By increasing the velocity of the stream between the pipeline and the seabed, shear stress on the seabed was enhanced. This localized increase in shear stress causes the seabed under the pipe to erode more quickly and facilitates self-burial of the pipe. To facilitate self-burial, a nonmetallic vertical fin is fastened to the top of the pipeline. In this paper flow around a pipeline with and without a spoiler near a smooth wall is simulated with FLUENT version 6.1. It is found that the velocity affected the shear stress, and the height of the spoiler does not have an obvious effect on the shear stress.

scholarly journals Cadmium Pollution Impact on the Bacterial Community Structure of Arable Soil and the Isolation of the Cadmium Resistant Bacteria

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaoxia Yu ◽  
JinTong Zhao ◽  
Xiaoqing Liu ◽  
LiXin Sun ◽  
Jian Tian ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Contaminated Soils ◽  
Removal Rate ◽  
Illumina Miseq ◽  
Soil Samples ◽  
Arable Soil ◽  
Polluted Area ◽  
Resistant Bacteria ◽  
Cadmium Pollution ◽  
Different Seasons

Microorganisms play an important role in the remediation of cadmium pollution in the soil and their diversity can be affected by cadmium. In this study, the bacterial community in arable soil samples collected from two near geographical sites, with different degrees of cadmium pollution at three different seasons, were characterized using Illumina MiSeq sequencing. The result showed that cadmium is an important factor to affect the bacterial diversity and the microbial communities in the high cadmium polluted area (the site H) had significant differences compared with low cadmium polluted area (the site L). Especially, higher concentrations of Cd significantly increased the abundance of Proteobacteria and Gemmatimonas whereas decreased the abundance of Nitrospirae. Moreover, 42 Cd-resistant bacteria were isolated from six soil samples and evaluated for potential application in Cd bioremediation. Based on their Cd-MIC [minimum inhibitory concentration (MIC) of Cd2+], Cd2+ removal rate and 16S rDNA gene sequence analyses, three Burkholderia sp. strains (ha-1, hj-2, and ho-3) showed very high tolerance to Cd (5, 5, and 6 mM) and exhibited high Cd2+ removal rate (81.78, 79.37, and 63.05%), six Bacillus sp. strains (151-5,151-6,151-13, 151-20, and 151-21) showed moderate tolerance to Cd (0.8, 0.4, 0.8, 0.4, 0.6, and 0.4 mM) but high Cd2+ removal rate (84.78, 90.14, 82.82, 82.39, 81.79, and 84.17%). Those results indicated that Burkholderia sp. belonging to the phylum Proteobacteria and Bacillus sp. belonging to the phylum Firmicutes have developed a resistance for cadmium and may play an important role in Cd-contaminated soils. Our study provided baseline data for bacterial communities in cadmium polluted soils and concluded that Cd-resistant bacteria have potential for bioremediation of Cd-contaminated soils.

Research on the Field Test of Desilting and Bank-Strengthening for the Yellow River

2006 ◽  
Author(s):  
Yanqiang Chen ◽  
Xianwu Luo ◽  
Hongyuan Xu ◽  
Wei Shi
Keyword(s):  
Field Test ◽  
Flow Rate ◽  
Yellow River ◽  
Transportation System ◽  
The Yellow River ◽  
High Concentration ◽  
Long Distance ◽  
River Sand ◽  
Obvious Effect ◽  
The Cost

Due to the large amount of sand in the Yellow River water, the sediment accumulation of the sand in the lower reaches of the river has been increasing for years. In order to control the Yellow River flood, the height of the stream channel of this river should be decreased, and the banks have to be widened and its height should be increased. Desilting and bank-strengthening is an effective path to reinforce the banks of the Yellow River by taking advantages of the silt in the river appropriately. In the Desilting and bank-strengthening project, owing to the long distance of transportation of the sand, three parallel submersible liquid-solid pumps are operated together with one or two slurry pumps in series. This paper treats the field test of the Yellow River sand transportation system. Based on the on-site experiment, the relationship between the transportation efficiency and sand properties, the resistance of pipeline, etc has been investigated. It is noted that the amount of sand increased the resistance of pipeline, and sand concentration had obvious effect on transportation efficiency. With the same flow-rate, the larger sand concentration is, the less time is needed to transport the same amount of sand, and the less the cost of both power consumption and the consumption water would be; With the same sand concentration, the larger the flow-rate is, the larger the production output of sand transportation and economic profits would be achieved during the same operation period. Thus, the transportation system should be recommended to run in the condition of as large flow-rate and as high concentration as possible so that the working time and the cost of production would be reduced, and better economic performance was available.

Generation of Square Cavity Using Planetary EDM

2014 ◽  
Vol 1036 ◽  
pp. 314-319 ◽  
Author(s):  
Vishal John Mathai ◽  
Harshit K. Dave ◽  
Keyur P. Desai
Keyword(s):  
Material Removal ◽  
Tool Path ◽  
Removal Rate ◽  
Planetary Motion ◽  
Tool Electrode ◽  
Electrical Parameters ◽  
Machining Processes ◽  
Response Characteristics ◽  
Wide Range ◽  
Pulse On Time

The design and manufacturing of complex shaped 3D features have a wide range of applications in todays manufacturing industries. With machining of hard materials continues to attract much interest in this field, EDM remains an indispensable process to carry out this purpose despite its limitations compared to conventional machining processes in terms of material removal rate and surface quality. Many process improvement techniques have been reported by researchers to overcome these limitations and out of them, incorporation of tool electrode kinematics is observed to have a significant effect. In the present investigation, an attempt has been made to study the effectiveness of two different tool motions in the generation of non-circular cavities. Tool electrode is moved on planetary and diagonal paths during this study. Effects of various electrical and non-electrical parameters on EDM responses have been studied. Current, pulse ON time and voltage are considered as the electrical parameters while tool kinematics parameters like tool path offset and scanning speed have been selected as the non-electrical parameters. Experiments have been carried out the study the effect of tool movement on planetary and diagonal path on different response characteristics viz. Material removal rateand Wear Ratio. It has been observed that planetary motion is a better strategy than diagonal motion for the generation of non-circular cavities in terms of achievement of the response characteristics. The results observed are critically discussed.

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