scholarly journals Antibacterial Activity of Chrysanthemum buds Crude Extract Against Cronobacter sakazakii and Its Application as a Natural Disinfectant

2021 ◽  
Vol 11 ◽  
Author(s):  
Yunhe Chang ◽  
Min Xing ◽  
Xinying Hu ◽  
Hongxia Feng ◽  
Yao Wang ◽  
...  

Cronobacter sakazakii is an opportunistic food-borne pathogen that endangers the health of neonates and infants. This study aims to elucidate the antibacterial activity and mechanism of Chrysanthemum buds crude extract (CBCE) against C. sakazakii and its application as a natural disinfectant. The antibacterial activity was evaluated by the determination of the diameter of inhibition zone (DIZ), minimum inhibitory concentration (MIC), and minimum bactericide concentration (MBC). The antibacterial mechanism was explored based on the changes of growth curve assay, intracellular ATP concentration, membrane potential, intracellular pH (pHin), content of soluble protein and nucleic acid, and cell morphology. Finally, the inactivation effects of CBCE against C. sakazakii in biofilm on stainless steel tube, tinplate, glass, and polystyrene were evaluated. The results showed that the DIZ, MIC, and MBC of CBCE against C. sakazakii were 14.55 ± 0.44–14.84 ± 0.38 mm, 10 mg/mL, and 20 mg/mL, respectively. In the process of CBCE acting on C. sakazakii, the logarithmic growth phase of the tested bacteria disappeared, and the concentrations of intracellular ATP, pHin, bacterial protein, and nucleic acid were reduced. Meanwhile, CBCE caused the cell membrane depolarization and leakage of cytoplasm of C. sakazakii. In addition, about 6.5 log CFU/mL of viable C. sakazakii in biofilm on stainless steel tube, tinplate, glass, and polystyrene could be inactivated after treatment with 1 MIC of CBCE for 30 min at 25°C. These findings reveal the antibacterial activity and mechanism of CBCE against C. sakazakii and provide a possibility of using a natural disinfectant to kill C. sakazakii in the production environment, packaging materials, and utensils.

Author(s):  
A. E. Gorodetskii ◽  
V. L. Bukhovets ◽  
R. Kh. Zalavutdinov ◽  
A. P. Zakharov

2014 ◽  
Vol 1081 ◽  
pp. 270-274
Author(s):  
Zui Xian Yu ◽  
Xue Sheng Wang ◽  
Qin Zhu Chen

A new preparation technique of carbon steel/stainless steel clad tube was introduced, and the contact surface was well combined. Meanwhile, with the using of tube heat exchanger, the experiment on the heat transfer performance of the clad tube was done. Comparing the 10/316 clad tube and the 316 stainless steel tube, the effects on the heat transfer performance of 316 stainless steel tube attached to carbon steel was evaluated. It is showed that overall heat transfer coefficient of 10/316 clad tubes is higher than that of stainless steel tube. The average heat transfer coefficient of 10/316 clad tubes is about 18.7%~34.4% higher than that of stainless steel tube. Experimental investigation indicates that, by brazing and cold drawing, the 10/316 clad tube was well combined and the thermal conductivity was better than that of stainless steel tube.


2012 ◽  
Vol 3 (3) ◽  
pp. 243-250
Author(s):  
A. Loosveld ◽  
W. De Waele ◽  
K. Faes ◽  
O. Zaitov

The goal of this master thesis is to realize and investigate leak tightness of joints produced by theelectromagnetic pulse (EMP) crimping process. This way of joining metals has gained more attention lately.With EMP welding, leak tight joints can already be achieved. However, the crimping process has somemajor advantages over EMP welding like the fact that more material combinations are possible and itrequires less energy. To realize the leak tightness, two kinds of sealing materials are used: O-rings andadhesives. The workpieces consist of an aluminium or stainless steel tube which is crimped on a solidaluminium mandrel with circumferential grooves in it. First, some preliminary tests are performed todetermine how much the tubes deform in the grooves. This deformation mainly depends on the appliedcharging voltage and the geometry of the groove. With this information, it is possible to estimate the amountof compression an O-ring would undergo when placed inside this groove. On other workpieces, adhesiveswill be applied. Several test procedures can be conducted on the parts to investigate leak tightness. Theresults of a helium test and a pressure burst test on the first test series conducted at the Walloon researchcentre CEWAC already showed that the use of O-rings can be effective.


Author(s):  
Jun Fang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Zhengjun Yao

In order to achieve the precision bending deformation, the effects of process parameters on springback behaviors should be clarified preliminarily. Taking the 21-6-9 high-strength stainless steel tube of 15.88 mm × 0.84 mm (outer diameter × wall thickness) as the objective, the multi-parameter sensitivity analysis and three-dimensional finite element numerical simulation are conducted to address the effects of process parameters on the springback behaviors in 21-6-9 high-strength stainless steel tube numerical control bending. The results show that (1) springback increases with the increasing of the clearance between tube and mandrel Cm, the friction coefficient between tube and mandrel fm, the friction coefficient between tube and bending die fb, or with the decreasing of the mandrel extension length e, while the springback first increases and then remains unchanged with the increasing of the clearance between tube and bending die Cb. (2) The sensitivity of springback radius to process parameters is larger than that of springback angle. And the sensitivity of springback to process parameters from high to low are e, Cb, Cm, fb and fm. (3) The variation rules of the cross section deformation after springback with different Cm, Cb, fm, fb and e are similar to that before springback. But under same process parameters, the relative difference of the most measurement section is more than 20% and some even more than 70% before and after springback, and a platform deforming characteristics of the cross section deformation is shown after springback.


2015 ◽  
Vol 47 (4) ◽  
pp. 454-460 ◽  
Author(s):  
Woonggi Hwang ◽  
Seunggi Bae ◽  
Jaeseong Kim ◽  
Sungsik Kang ◽  
Nogwon Kwag ◽  
...  

1996 ◽  
Vol 270 (2) ◽  
pp. H442-H446 ◽  
Author(s):  
C. M. Martin ◽  
A. Beltran-Del-Rio ◽  
A. Albrecht ◽  
R. R. Lorenz ◽  
M. J. Joyner

To determine whether local cholinergic mechanisms evoke nitric oxide (NO)-mediated flow-induced vasorelaxation, canine coronary artery rings without endothelium were suspended beneath an organ chamber that contained a stainless steel tube and a femoral artery segment with endothelium. The rings were superfused at a basal rate of 1 ml/min with physiological salt solution that was bubbled with 95% O2-5% CO2 and maintained at 37 degrees C. They were stretched to optimal length and contracted with prostaglandin F 2 alpha (2 x 10(-6) M). When flow through the stainless steel tube (direct superfusion) was increased from the basal rate of 1 to 4 ml/min, coronary force did not change. Superfusion of the rings (n = 8) with effluent from the femoral segment (endothelial superfusion) at 4 ml/min to study flow-induced vasodilation caused a 67.3 +/- 10.8% relaxation. Treatment of the segment with the NO synthase blocker NG-monomethyl-L-arginine (10(-4) M) eliminated the relaxation seen during endothelial superfusion (P < 0.05 vs. control). Application of atropine (10(-6) M) to additional femoral segments (n = 8) abolished the coronary relaxation observed during endothelial superfusion at 1 ml/ min, and the flow-induced relaxation observed at 4 ml/min was reduced from 64 +/- 8.3 to 27 +/- 5.6% (P < 0.05 vs. control). In studies on additional segments and rings (n = 6), the flow-induced relaxations at 4 ml/min of endothelial superfusion were blunted from 86 +/- 10 to 28 +/- 13% after the segments were treated with acetylcholinesterase (0.00028 U/min for 20 min). These data indicate that basal- and flow-induced release of NO from the vascular endothelium can be mediated by local cholinergic mechanisms. It is possible that flow causes acetylcholine release from certain endothelial cells, which stimulates NO release from these cells or from neighboring endothelial cells.


1999 ◽  
Vol 121 (2) ◽  
pp. 365-375 ◽  
Author(s):  
R. J. Benjamin ◽  
A. R. Balakrishnan

A model for nucleate pool boiling heat transfer of binary mixtures has been proposed based on an additive mechanism. The contributing modes of heat transfer are (i) the heat transferred by microlayer evaporation, (ii) the heat transferred by transient conduction during the reformation of the thermal boundary layer, and (iii) the heat transferred by turbulent natural convection. The model takes into account the microroughness of the heating surface which has been defined quantitatively. The model compares satisfactorily with data obtained in the present study and in the literature. These data were obtained on a variety of heating surfaces such as a vertical platinum wire, a horizontal stainless steel tube and flat horizontal aluminium, and stainless steel surfaces (with various surface finishes) thereby demonstrating the validity of the model.


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