scholarly journals Low-Temperature Plasma as an Approach for Inhibiting a Multi-Species Cariogenic Biofilm

2021 ◽  
Vol 11 (2) ◽  
pp. 570
Author(s):  
Leandro W. Figueira ◽  
Beatriz H. D. Panariello ◽  
Cristiane Y. Koga-Ito ◽  
Simone Duarte
Keyword(s):  
Low Temperature ◽  
Laser Scanning ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Plasma Device ◽  
Negative Controls ◽  
Promising Source

This study aimed to determine how low-temperature plasma (LTP) treatment affects single- and multi-species biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii formed on hydroxyapatite discs. LTP was produced by argon gas using the kINPen09™ (Leibniz Institute for Plasma Science and Technology, INP, Greifswald, Germany). Biofilms were treated at a 10 mm distance from the nozzle of the plasma device to the surface of the biofilm per 30 s, 60 s, and 120 s. A 0.89% saline solution and a 0.12% chlorhexidine solution were used as negative and positive controls, respectively. Argon flow at three exposure times (30 s, 60 s, and 120 s) was also used as control. Biofilm viability was analyzed by colony-forming units (CFU) recovery and confocal laser scanning microscopy. Multispecies biofilms presented a reduction in viability (log10 CFU/mL) for all plasma-treated samples when compared to both positive and negative controls (p < 0.0001). In single-species biofilms formed by either S. mutans or S. sanguinis, a significant reduction in all exposure times was observed when compared to both positive and negative controls (p < 0.0001). For single-species biofilms formed by S. gordonii, the results indicate total elimination of S. gordonii for all exposure times. Low exposure times of LTP affects single- and multi-species cariogenic biofilms, which indicates that the treatment is a promising source for the development of new protocols for the control of dental caries.

scholarly journals Development of a methodology for measuring the evolution of duplex stainless-steel low-temperature plasma nitrided phases expansion using confocal laser scanning microscopy

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Carlos Eduardo Alves Feitosa ◽  
Rodrigo Perito Cardoso ◽  
Silvio Francisco Brunatto
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Innovative Methodology ◽  
Different Response

Samples of duplex stainless steel SAF 2507 were low-temperature plasma nitrided to characterize separately, on the surface, the behavior of its ferrite and austenite phases in relation to two competing processes, that is, one caused by enrichment by nitrogen, resulting in possible expansion, and the other caused by the removal of superficial atoms via sputtering, which may lead to the retraction of the studied phases. Since these phases have different different compositions and crystalline structures, of which the diffusivity and solubility of nitrogen in them are dependent, a different response for each type of phase can be expected. In this article, an innovative methodology has been developed to quantify and clarify which effects are predominant in the course of nitriding for each of these phases. The results indicate that phase expansion prevails over sputtering.

scholarly journals Bacteria on Catheters in Patients Undergoing Peritoneal Dialysis

2013 ◽  
Vol 33 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Maria Pihl ◽  
Julia R. Davies ◽  
Ann-Cathrine Johansson ◽  
Gunnel Svensäter
Keyword(s):  
Peritoneal Dialysis ◽  
Laser Scanning ◽  
Close Association ◽  
Bacterial Species ◽  
Clinical Signs ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rrna Gene ◽  
Micro Organisms

♦BackgroundPeritonitis is the leading cause of morbidity for peritoneal dialysis (PD) patients, and microbial biofilms have previously been identified on catheters from infected patients. However, few studies of catheters from patients without clinical signs of infection have been undertaken. The aim of the present study was to investigate the extent to which bacteria are present on catheters from PD patients with no symptoms of infection.♦MethodsMicrobiologic culturing under aerobic and anaerobic conditions and confocal laser scanning microscopy were used to determine the distribution of bacteria on PD catheters from 15 patients without clinical signs of infection and on catheters from 2 infected patients. The 16S rRNA gene sequencing technique was used to identify cultured bacteria.♦ResultsBacteria were detected on 12 of the 15 catheters from patients without signs of infection and on the 2 catheters from infected patients. Single-species and mixed-microbial communities containing up to 5 species were present on both the inside and the outside along the whole length of the colonized catheters. The bacterial species most commonly found were the skin commensals Staphylococcus epidermidis and Propionibacterium acnes, followed by S. warneri and S. lugdunensis. The strains of these micro-organisms, particularly those of S. epidermidis, varied in phenotype with respect to their tolerance of the major classes of antibiotics.♦ConclusionsBacteria were common on catheters from patients without symptoms of infection. Up to 4 different bacterial species were found in close association and may represent a risk factor for the future development of peritonitis in patients hosting such micro-organisms.

Impact of Hydrodynamics on Oral Biofilm Strength

2009 ◽  
Vol 88 (10) ◽  
pp. 922-926 ◽  
Author(s):  
E. Paramonova ◽  
O.J. Kalmykowa ◽  
H.C. van der Mei ◽  
H.J. Busscher ◽  
P.K. Sharma
Keyword(s):  
Laser Scanning ◽  
Periodontal Diseases ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Oral Biofilm ◽  
Actinomyces Naeslundii ◽  
Mechanical Removal ◽  
Hydrodynamic Shear ◽  
Oral Biofilms

Mechanical removal of oral biofilms is ubiquitously accepted as the best way to prevent caries and periodontal diseases. Removal effectiveness strongly depends on biofilm strength. To investigate the influence of hydrodynamics on oral biofilm strength, we grew single- and multi-species biofilms of Streptococcus oralis J22, Actinomyces naeslundii TV14-J1, and full dental plaque at shear rates ranging from 0.1 to 50 1/sec and measured their compressive strength. Subsequently, biofilm architecture was evaluated by confocal laser scanning microscopy. Multi-species biofilms were stronger than single-species biofilms, with strength values ranging from 6 to 51 Pa and from 5 to 17 Pa, respectively. In response to increased hydrodynamic shear, biofilm strength decreased, and architecture changed from uniform carpet-like to more “fluffy” with higher thickness. S. oralis biofilms grown under variable shear of 7 and 50 1/sec possessed properties intermediate of those measured at the respective single shears.

The Influence on Hydrophilic after the Surface Treatment of the Singed Gray Fabric by the Low Temperature Plasma

2011 ◽  
Vol 331 ◽  
pp. 708-712
Author(s):  
Peng Li ◽  
Shen Jun Zhang ◽  
Shou Guo Wang
Keyword(s):  
Low Temperature ◽  
Surface Treatment ◽  
Plasma Treatment ◽  
Cotton Fabric ◽  
Scientific Basis ◽  
Surface Treatments ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Plasma Technique ◽  
Plasma Device

We carried on the surface treatments to the cotton fabric (singed and hadn't been singed) with the low temperature plasma device. We studied the desizing performances, compared the capillaries. The results showed that after the same plasma treatment, the intensity of the singed hydrophilic was similar to those that hadn't been singed yet. We also explained the influence on hydrophilic, the results provide a scientific basis for the using of the pretreatment plasma technique in the future.

A Novel Continuously Initiated Polymerization by One-Atmosphere Low Temperature Plasma Device

2005 ◽  
Vol 7 (2) ◽  
pp. 2758-2760 ◽  
Author(s):  
You Qingliang ◽  
Meng Yuedong ◽  
Wang Jianhua ◽  
Ou Qiongrong ◽  
Xu Xu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Plasma Device

scholarly journals The vicK gene of Streptococcus mutans mediates its cariogenicity via exopolysaccharides metabolism

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yalan Deng ◽  
Yingming Yang ◽  
Bin Zhang ◽  
Hong Chen ◽  
Yangyu Lu ◽  
...  
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Gas Chromatography Mass Spectrometry ◽  
Extracellular Polysaccharides ◽  
Confocal Laser

AbstractStreptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.

scholarly journals Characterization of Binary Biofilms of Listeria monocytogenes and Lactobacillus and Their Response to Chlorine Treatment

2021 ◽  
Vol 12 ◽  
Author(s):  
Magdalena A. Olszewska ◽  
Francisco Diez-Gonzalez
Keyword(s):  
Listeria Monocytogenes ◽  
Laser Scanning ◽  
Spatial Organization ◽  
Volume Ratio ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Interspecies Interactions ◽  
Biofilm Thickness ◽  
Cell Counts

In nature, Listeria may interact competitively and cooperatively with other organisms, resulting in unique spatial organization and functions for cells within the community. This study was undertaken to characterize the biofilm architecture of binary biofilms of Listeria monocytogenes and Lactobacillus species and to assess their effect on the survival of Listeria during exposure to hypochlorite. Three L. monocytogenes strains, ATCC 19115 (Lm5), ATCC 19117 (Lm7), and Coleslaw (LmC), were selected and combined individually with three Lactobacillus strains: L. fermentum (Lf), L. bavaricus (Lb), and L. plantarum (Lp). In binary Lm-Lp biofilms, the Lm cell counts were similar to single-species biofilms (8.5 log CFU/well), and the Lp cell numbers declined by 1.0 log CFU/well. In the presence of Lb, the Lm cell counts were reduced by 1.5 log CFU/well (p &lt; 0.05), whereas the Lf cell counts increased at least by 3.5 log CFU/well. Confocal laser scanning microscopy (CLSM) determined that interspecies interactions significantly affected the spatial organization of three binary biofilms. Biofilm surface-to-volume ratio increased from 0.8 μm2/μm3 for Lm5 in the monoculture to 2.1 μm2/μm3 for Lm5-Lp in the dual-species model (p &lt; 0.05), and was characterized by a thicker structure with a largely increased surface area. Biofilm roughness increased from 0.2 for Lm7 to 1.0 for Lm7-Lb biofilms (p &lt; 0.05), which appeared as interspecific segregation. Biofilm thickness increased from 34.2 μm for LmC to 46.3 μm for LmC–Lf (p &lt; 0.05), which produced flat and compact structures that covered the entire surface available. The biomass of the extracellular matrix was higher in the case of some binary biofilms (p &lt; 0.05); however, this effect was dependent upon the species pair. When treated with hypochlorite, Lm5 in binary biofilms had an approximately 1.5 log CFU/well greater survival than individually. The unique spatial organization and greater protein production may explain the protective effect of Lp after hypochlorite exposure.

scholarly journals Microstructure and Charpy Impact Toughness of a 2.25Cr-1Mo-0.25V Steel Weld Metal

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3013 ◽  
Author(s):  
Kefan Wu ◽  
Yingjie Yan ◽  
Rui Cao ◽  
Xinyu Li ◽  
Yong Jiang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Weld Metal ◽  
Power Plants ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Granular Bainite ◽  
Confocal Laser ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness

The demand for heat-resistant steel has increased owing to its utility in numerous devices that must withstand high steam pressures and high temperatures, such as turbine rotors and blades in ultra-supercritical power plants. It is inevitable to join heat-resistance steel part by welding method, so it is important to maintain the toughness of the weld metals. In this study, the microstructure, low-temperature impact toughness, and fracture surface of as-welded and post-weld heat treatment (PWHT) of 2.25Cr-1Mo-0.25V weld metal were investigated. The microstructures of the as-welded and PWHT specimens are granular bainite and ferrite, respectively. This work revealed the relationship between effective microstructure nearby crack initiation origin and low temperature impact toughness for both the as-welded and PWHT specimens. The evolution of the microstructure and prior austenite was then investigated using confocal laser scanning microscopy (CLSM) to observe the formation of coarse ferrite grain structures. A suggestion for enhancing the low-temperature toughness was provided based on the effect of adjusting Mn content and forming acicular ferrite.

The application of LIBS and other techniques on Chinese low temperature glaze

MRS Advances ◽  
2017 ◽  
Vol 2 (39-40) ◽  
pp. 2081-2094 ◽  
Author(s):  
Liang Qu ◽  
Xinqiang Zhang ◽  
Hongying Duan ◽  
Rui Zhang ◽  
Guanghua Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Inductively Coupled Plasma ◽  
Laser Scanning ◽  
Porcelain Body ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Breakdown Spectroscopy ◽  
Alkali Glass ◽  
Metal Body ◽  
Glazed Porcelain

ABSTRACT The focus of this paper is on analysis, comparison and research on the colorful low-temperature, lead-containing overglazes on glazed porcelain body and on the enamel glazes on the metal body of the Qing Dynasty by adopting several analytical methods. Analysis and tests on the element, boron in overglaze on glazed porcelain body and enamel glaze on metal body, were performed using laser induced breakdown spectroscopy (LIBS), and the results showed that Cloisonné enamel, painted enamel and Falangcai samples contained boron, while Famille Rose (Fencai) samples did not contain boron. Meanwhile, such analysis methods as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), energy dispersive X-ray spectroscopy (EDXRF), Micro-Raman, stereomicroscope and Confocal laser scanning microscopy (CLSM) were used to test and observe the element composition, crystal composition and microstructure of the samples. The results illustrated that matrix glaze of Cloisonné enamel, painted enamel and Falangcai was the same. The yellow glaze was a lead-alkali glass and other color glazes were boron-lead-alkali glass, while all color glazes of Famille Rose were lead-alkali glass. Colorful low-temperature overglaze on glazed porcelain body and enamel glaze on metal body had a common practice and technology in the use of opacifiers and colorants. Compared to painted enamel, the painting technique of Famille Rose was more complicated, and effect was apparently praised as being superior.

scholarly journals Coaggregation by the Freshwater Bacterium Sphingomonas natatoria Alters Dual-Species Biofilm Formation

2009 ◽  
Vol 75 (12) ◽  
pp. 3987-3997 ◽  
Author(s):  
K. R. Min ◽  
A. H. Rickard
Keyword(s):  
Glass Surface ◽  
Laser Scanning ◽  
Micrococcus Luteus ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Biofilm Growth ◽  
Biofilm Development ◽  
Glass Surfaces ◽  
Sphingomonas Natatoria

ABSTRACTCoaggregation is hypothesized to enhance freshwater biofilm development. To investigate this hypothesis, the ability of the coaggregating bacteriumSphingomonas natatoriato form single- and dual-species biofilms was studied and compared to that of a naturally occurring spontaneous coaggregation-deficient variant. Attachment assays using metabolically inactive cells were performed using epifluorescence and confocal laser scanning microscopy. Under static and flowing conditions, coaggregatingS. natatoria2.1gfp cells adhered to glass surfaces to form diaphanous single-species biofilms. When glass surfaces were precoated with coaggregation partnerMicrococcus luteus2.13 cells,S. natatoria2.1gfp cells formed densely packed dual-species biofilms. The addition of 80 mM galactosamine, which reverses coaggregation, mildly reduced adhesion to glass but inhibited the interaction and attachment to glass-surface-attachedM. luteus2.13 cells. As opposed to wild-type coaggregating cells, coaggregation-deficientS. natatoria2.1COGgfp variant cells were retarded in colonizing glass and did not interact with glass-surface-attachedM. luteus2.13 cells. To determine if coaggregation enhances biofilm growth and expansion, viable coaggregatingS. natatoria2.1gfp cells or the coaggregation-deficient variantS. natatoria2.1COGgfp cells were coinoculated in flow cells with viableM. luteus2.13 cells and allowed to grow together for 96 h. CoaggregatingS. natatoria2.1gfp cells outcompetedM. luteus2.13 cells, and 96-h biofilms were composed predominantly ofS. natatoria2.1gfp cells. Conversely, when coaggregation-deficientS. natatoria2.1COGgfp cells were coinoculated withM. luteus2.13 cells, the 96-h biofilm contained few coaggregation-deficientS. natatoria2.1 cells. Thus, coaggregation promotes biofilm integration by facilitating attachment to partner species and likely contributes to the expansion of coaggregatingS. natatoria2.1 populations in dual-species biofilms through competitive interactions.

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