scholarly journals Undulatory topographical waves for flow-induced foulant sweeping

2019 ◽  
Vol 5 (11) ◽  
pp. eaax8935 ◽  
Author(s):  
Hangil Ko ◽  
Hyun-Ha Park ◽  
Hyeokjun Byeon ◽  
Minsu Kang ◽  
Jaeha Ryu ◽  
...  
Keyword(s):  
Composite Material ◽  
Biofilm Formation ◽  
Effective Means ◽  
Material Surface ◽  
Initial Attachment ◽  
Dynamic Motion ◽  
New Class ◽  
Efficient Suppression ◽  
Good Biocompatibility

Diverse bioinspired antifouling strategies have demonstrated effective fouling-resistant properties with good biocompatibility, sustainability, and long-term activity. However, previous studies on bioinspired antifouling materials have mainly focused on material aspects or static architectures of nature without serious consideration of kinetic topographies or dynamic motion. Here, we propose a magnetically responsive multilayered composite that can generate coordinated, undulatory topographical waves with controlled length and time scales as a new class of dynamic antifouling materials. The undulatory surface waves of the dynamic composite induce local and global vortices near the material surface and thereby sweep away foulants from the surface, fundamentally inhibiting their initial attachment. As a result, the dynamic composite material with undulating topographical waves provides an effective means for efficient suppression of biofilm formation without surface modification with chemical moieties or nanoscale architectures.

scholarly journals Antibiotic-decorated titanium with enhanced antibacterial activity through adhesive polydopamine for dental/bone implant

2014 ◽  
Vol 11 (95) ◽  
pp. 20140169 ◽  
Author(s):  
Shu He ◽  
Ping Zhou ◽  
Linxin Wang ◽  
Xiaoling Xiong ◽  
Yifei Zhang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Photoelectron Spectroscopy ◽  
Biofilm Formation ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
One Step ◽  
Bone Graft Substitutes ◽  
Good Biocompatibility ◽  
Adhesive Proteins

Implant-associated infections, which are normally induced by microbial adhesion and subsequent biofilm formation, are a major cause of morbidity and mortality. Therefore, practical approaches to prevent implant-associated infections are in great demand. Inspired by adhesive proteins in mussels, here we have developed a novel antibiotic-decorated titanium (Ti) material with enhanced antibacterial activity. In this study, Ti substrate was coated by one-step pH-induced polymerization of dopamine followed by immobilization of the antibiotic cefotaxime sodium (CS) onto the polydopamine-coated Ti through catechol chemistry. Contact angle measurement and X-ray photoelectron spectroscopy confirmed the presence of CS grafted on the Ti surface. Our results demonstrated that the antibiotic-grafted Ti substrate showed good biocompatibility and well-behaved haemocompatibility. In addition, the antibiotic-grafted Ti could effectively prevent adhesion and proliferation of Escherichia coli (Gram-negative) and Streptococcus mutans (Gram-positive). Moreover, the inhibition of biofilm formation on the antibiotic-decorated Ti indicated that the grafted CS could maintain its long-term antibacterial activity. This modified Ti substrate with enhanced antibacterial activity holds great potential as implant material for applications in dental and bone graft substitutes.

Tertiary nitrification in pilot-plant plug-flow fixed-film reactors with long-term ammonium deficiency

1994 ◽  
Vol 29 (10-11) ◽  
pp. 61-67 ◽  
Author(s):  
M. Fruhen ◽  
K. Böcker ◽  
S. Eidens ◽  
D. Haaf ◽  
M. Liebeskind ◽  
...  
Keyword(s):  
Pilot Plant ◽  
Effective Means ◽  
Plug Flow ◽  
Nitrification Rate ◽  
Industrial Project ◽  
Transfer Processes ◽  
Fixed Film ◽  
Film Reactor ◽  
Observation Period

The objective of this study is to investigate to what extent the nitrification capacity of a pilot-plant fixed-film reactor changes during extensive periods of nutrient supply deficiency. The examined pilot-plant was an upflow reactor filled with swelling clay of medium grain size (6 to 8 mm). The experiments revealed that the maximum nitrification rate remained practically constant during the first weeks after the onset of unregulated ammonium supply. The capacity declined slowly, dropping to approximately 66% of the initial capacity after about ten weeks. Still ammonium peaks of up to 8 mg/l were readily nitrified throughout the entire period of the experiment. The reduction in nitrification capacity during the observation period did not result from decay processes of biomass but from the reactor becoming blocked and thus hampering transfer processes. It could be observed that the detached organisms attached again further up. This semi-industrial project demonstrated that a plug-flow fixed-film reactor can be used as effective means of tertiary nitrification.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

scholarly journals RNAseq Reveals Differential Gene Expression Contributing to Phytophthora nicotianae Adaptation to Partial Resistance in Tobacco

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 656
Author(s):  
Jing Jin ◽  
Rui Shi ◽  
Ramsey Steven Lewis ◽  
Howard David Shew
Keyword(s):  
Partial Resistance ◽  
Molecular Mechanisms ◽  
Biological Activities ◽  
Effective Means ◽  
Phytophthora Nicotianae ◽  
Economic Losses ◽  
Black Shank ◽  
Differential Gene ◽  
Go Terms

Phytophthora nicotianae is a devastating oomycete plant pathogen with a wide host range. On tobacco, it causes black shank, a disease that can result in severe economic losses. Deployment of host resistance is one of the most effective means of controlling tobacco black shank, but adaptation to complete and partial resistance by P. nicotianae can limit the long-term effectiveness of the resistance. The molecular basis of adaptation to partial resistance is largely unknown. RNAseq was performed on two isolates of P. nicotianae (adapted to either the susceptible tobacco genotype Hicks or the partially resistant genotype K 326 Wz/Wz) to identify differentially expressed genes (DEGs) during their pathogenic interactions with K 326 Wz/Wz and Hicks. Approximately 69% of the up-regulated DEGs were associated with pathogenicity in the K 326 Wz/Wz-adapted isolate when sampled following infection of its adapted host K 326 Wz/Wz. Thirty-one percent of the up-regulated DEGs were associated with pathogenicity in the Hicks-adapted isolate on K 326 Wz/Wz. A broad spectrum of over-represented gene ontology (GO) terms were assigned to down-regulated genes in the Hicks-adapted isolate. In the host, a series of GO terms involved in nuclear biosynthesis processes were assigned to the down-regulated genes in K 326 Wz/Wz inoculated with K 326 Wz/Wz-adapted isolate. This study enhances our understanding of the molecular mechanisms of P. nicotianae adaptation to partial resistance in tobacco by elucidating how the pathogen recruits pathogenicity-associated genes that impact host biological activities.

scholarly journals Thiazole Analogues of the Marine Alkaloid Nortopsentin as Inhibitors of Bacterial Biofilm Formation

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 81
Author(s):  
Anna Carbone ◽  
Stella Cascioferro ◽  
Barbara Parrino ◽  
Daniela Carbone ◽  
Camilla Pecoraro ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Thiazole Derivatives ◽  
Gram Positive ◽  
Lead Compounds ◽  
New Class ◽  
Marked Selectivity ◽  
Global Threat ◽  
New Compounds ◽  
Reference Strains

Anti-virulence strategy is currently considered a promising approach to overcome the global threat of the antibiotic resistance. Among different bacterial virulence factors, the biofilm formation is recognized as one of the most relevant. Considering the high and growing percentage of multi-drug resistant infections that are biofilm-mediated, new therapeutic agents capable of counteracting the formation of biofilms are urgently required. In this scenario, a new series of 18 thiazole derivatives was efficiently synthesized and evaluated for its ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923 and S. aureus ATCC 6538 and the Gram-negative strain Pseudomonas aeruginosa ATCC 15442. Most of the new compounds showed a marked selectivity against the Gram-positive strains. Remarkably, five compounds exhibited BIC50 values against S. aureus ATCC 25923 ranging from 1.0 to 9.1 µM. The new compounds, affecting the biofilm formation without any interference on microbial growth, can be considered promising lead compounds for the development of a new class of anti-virulence agents.

scholarly journals Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 724
Author(s):  
Noack ◽  
Heyns ◽  
Rodenwoldt ◽  
Edwards
Keyword(s):  
Management Strategies ◽  
Camera Traps ◽  
Spatially Explicit ◽  
Conservation Areas ◽  
Term Survival ◽  
New Class ◽  
Capture Recapture ◽  
Wildlife Populations ◽  
Effective Conservation

The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km2, the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.

scholarly journals Efficient suppression of biofilm formation by a nucleic acid aptamer

2015 ◽  
Vol 73 (6) ◽  
Author(s):  
Yi Ning ◽  
Lijuan Cheng ◽  
Min Ling ◽  
Xinru Feng ◽  
Lingli Chen ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Biofilm Formation ◽  
Efficient Suppression

Use of small cannulated screws for fixation in foot surgery

2000 ◽  
Vol 90 (5) ◽  
pp. 240-246 ◽  
Author(s):  
AE Burns
Keyword(s):  
Effective Means ◽  
Bone Screws ◽  
Cannulated Screws ◽  
Implant Fixation ◽  
Foot Surgery ◽  
Fixation Failure ◽  
Untoward Event ◽  
Patient Noncompliance

Use of cannulated bone screws, as compared with use of traditional bone screws, has been reported to decrease surgical time, allow for more precise screw placement, and reduce sources of error. Cannulation of the smaller-size screws that are routinely used in foot surgery has not been available until the last few years. This article reports on the use of the small cannulated screws manufactured by Alphatec Manufacturing, Inc (Palm Desert, California). The screw sizes available in the Mini Lag Screw System are 2.7, 3.5, and 4.0 mm. A long-term clinical and radiographic prospective evaluation of 70 procedures performed on 49 patients was conducted. The follow-up time for all patients was 2 years. None of the 70 implants fractured, and seven procedures (in seven patients) resulted in some type of implant-fixation failure. All of the fixation failures, however, appeared to be related to an untoward event or patient noncompliance. These smaller cannulated screws proved to be a reliable and effective means of fixation in foot surgery.

Is Age the New Class? Economic Crisis and Demographics in European Politics

2016 ◽  
Vol 43 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Jan Erk
Keyword(s):  
Age Groups ◽  
The Political ◽  
Economic Downturn ◽  
New Class ◽  
Political Landscape ◽  
Younger Age ◽  
Material Interests ◽  
Post War ◽  
The Welfare State

As the crisis turns into long-term economic downturn, younger age-groups in Europe seem to be hit with higher levels of unemployment while the welfare state is steadily shrinking. The young have suddenly become a social group united by collective material interests, but does this translate into a sense of a collective political interest? The paper examines to what extent the dominant class-based social science of the post-war years can help us understand the politics of age-groups. The analysis highlights four changes since post-war years: the workplace has changed, impacting socialization; modern media has changed, impacting mobilization; the political landscape is fairly institutionalized, tempering the possibilities for new political concerns to find voice; and those who would define and articulate the political priorities of the young are leaving the Old Continent.

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