نتایج جستجو برای: penetration of bacteria

تعداد نتایج: 21176608  

Journal: :Antimicrobial agents and chemotherapy 2005
Kimberly K Jefferson Donald A Goldmann Gerald B Pier

When bacteria assume the biofilm mode of growth, they can tolerate levels of antimicrobial agents 10 to 1,000 times higher than the MICs of genetically equivalent planktonic bacteria. The properties of biofilms that give rise to antibiotic resistance are only partially understood. Inhibition of antibiotic penetration into the biofilm may play a role, but this has not been proven directly. In th...

Journal: :The Journal of General Physiology 2003
Samuel E. Hill

It is shown that disappearance of the light of luminous bacteria may be used as a criterion of cell penetration; that luminous bacteria are cytolyzed by water, hypotonic solutions, and by freely penetrating solutions; that luminous bacteria are not injured by hydrogen or hydroxyl ions in the external solutions within the range of pH values employed with the ammonium salts and that therefore dis...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389

abstract this study was carried out to compare disinfecting effects of nanosilver with other feed disinfectants on layer hen performance, immune system, gastrointestinal microflora and intestinal morphology. total of 90 layers (lsl) were divided into five groups consisting: 1-control, 2- formalin (200 ppm), 3- formaycin (200 ppm), 4- nanosilver in drinking water (7.5 ppm) and 5-nanosilver in f...

باغبانان, علیرضا, رازانی, مهدی, رمضانیفر, فرشاد, هاشم الحسینی, حمید,

Archaeological sites in desert areas are at risk for destroying and reburied with sand dunes by sand storms. One of the most important issues for archaeologist and conservators in these regions are maintenance of archaeological remains, during the excavation process and after it, There are several sand dune stabilization methods such as mechanical dune stabilization, mulch or protective screen,...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده فنی و مهندسی 1389

در سالیان اخیر شاهد حرکتی مستمر از تحقیقات صرفا تئوری به تحقیقات کاربردی بخصوص در زمینه پردازش اطلاعات ، برای مسائلی که برای آنها راه حلی موجود نیست و یا براحتی قابل حل نیستند بوده ایم. با عنایت به این امر ، علاقه ای فزاینده ای در توسعه تئوریکی سیستمهای دینامیکی هوشمند مدل آزاد-که مبتنی بر داده های تجربی میباشند – ایجاد شده است. ann ها جزایی از این دسته از سیستمهای مکانیکی هستند که با پردازش رو...

Journal: :journal of lasers in medical sciences 0
abdollah ghorbanzadeh endodontic department, school of dentistry, tehran university of medical sciences, tehran, iran mohsen aminsobhani endodontic department, school of dentistry, tehran university of medical sciences and aja university of medical sciences, tehran, iran khosro sohrabi laser research center of dentistry, school of dentistry, tehran university of medical sciences, tehran, iran nasim chiniforush laser research center of dentistry, school of dentistry, tehran university of medical sciences, tehran, iran sarvenaz ghafari endodontic department, school of dentistry, kermanshah university of medical sciences, kermanshah, iran ahmad reza shamshiri epidemiologist, tehran university of medical sciences, tehran, iran

introduction: the penetration depth of irrigating solutions in dentinal tubules is limited; consequently, bacteria can remain inside dentinal tubules after the cleaning and shaping of the root canal system. therefore, new irrigation systems are required to increase the penetration depth of irrigating solutions in dentinal tubules. methods: a comparative study regarding the penetration depth of ...

Journal: :Journal of endodontics 2009
Payman Kakoli Renu Nandakumar Elaine Romberg Dwayne Arola Ashraf F Fouad

The aim of this study was to determine the effects of patient's age on the prevalence and depth of bacterial penetration inside dentinal tubules. Fifty-six single-rooted teeth were divided in two groups based on the patient's age: young (ages 18-25) and old (age >or=60). Teeth were instrumented and inoculated with a standardized bacterial load and incubated for 20 days. Histological analysis wa...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Shipra Vaishnava Cassie L Behrendt Anisa S Ismail Lars Eckmann Lora V Hooper

The intestinal epithelium is in direct contact with a vast microbiota, yet little is known about how epithelial cells defend the host against the heavy bacterial load. To address this question we studied Paneth cells, a key small intestinal epithelial lineage. We found that Paneth cells directly sense enteric bacteria through cell-autonomous MyD88-dependent toll-like receptor (TLR) activation, ...

Journal: :Applied and environmental microbiology 1989
P J Reynolds P Sharma G E Jenneman M J McInerney

The biological factors important in the penetration of Escherichia coli through anaerobic, nutrient-saturated, Ottawa sand-packed cores were studied under static conditions. In cores saturated with galactose-peptone medium, motile strains of E. coli penetrated four times faster than mutants defective only in flagellar synthesis. Motile, nonchemotactic mutants penetrated the cores faster than di...

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