480 research outputs found
Detection and quantification of 14 Campylobacter species in pet dogs reveals an increase in species richness in feces of diarrheic animals
<p>Abstract</p> <p>Background</p> <p>The genus <it>Campylobacter </it>includes many species, some of which are known human and animal pathogens. Even though studies have repeatedly identified domestic dogs as a risk factor for human campylobacteriosis, our understanding of <it>Campylobacter </it>ecology in this reservoir is limited. Work to date has focused primarily on a limited number of species using culture-based methods. To expand our understanding of <it>Campylobacter </it>ecology in dogs, a collection of fecal samples from 70 healthy and 65 diarrheic pet dogs were examined for the presence and levels of 14 <it>Campylobacter </it>species using quantitative PCR.</p> <p>Results</p> <p>It was found that 58% of healthy dogs and 97% of diarrheic dogs shed detectable levels of <it>Campylobacter </it>spp., with <it>C. coli, C. concisus, C. fetus, C. gracilis, C. helveticus, C. jejuni, C. lari, C. mucosalis, C. showae, C. sputorum </it>and <it>C. upsaliensis </it>levels significantly higher in the diarrheic population. Levels of individual <it>Campylobacter </it>species detected ranged from 10<sup>3 </sup>to 10<sup>8 </sup>organisms per gram of feces. In addition, many individual samples contained multiple species of <it>Campylobacter</it>, with healthy dogs carrying from 0-7 detectable species while diarrheic dogs carried from 0-12 detectable species.</p> <p>Conclusions</p> <p>These findings represent the largest number of <it>Campylobacter </it>species specifically tested for in animals and is the first report to determine quantifiable levels of <it>Campylobacter </it>being shed from dogs. This study demonstrates that domestic dogs can carry a wide range of <it>Campylobacter </it>species naturally and that there is a notable increase in species richness detectable in the diarrheic population. With several of the detected <it>Campylobacter </it>species known or emerging pathogens, these results are relevant to both ecological and public health discussions.</p
DNA Damage by Ionizing Radiation: Tandem Double Lesions by Charged Particles
Oxidative damages by ionizing radiation are the source of radiation-induced carcinogenesis, damage to the central nervous system, lowering of the immune response, as well as other radiation-induced damages to human health. Monte Carlo track simulations and kinetic modeling of radiation damages to the DNA employ available molecular and cellular data to simulate the biological effect of high and low LET radiation io the DNA. While the simulations predict single and double strand breaks and base damages, so far all complex lesions are the result of stochastic coincidence from independent processes. Tandem double lesions have not yet been taken into account. Unlike the standard double lesions that are produced by two separate attacks by charged particles or radicals, tandem double lesions are produced by one single attack. The standard double lesions dominate at the high dosage regime. On the other hand, tandem double lesions do not depend on stochastic coincidences and become important at the low dosage regime of particular interest to NASA. Tandem double lesions by hydroxyl radical attack of guanine in isolated DNA have been reported at a dosage of radiation as low as 10 Gy. The formation of two tandem base lesions was found to be linear with the applied doses, a characteristic of tandem lesions. However, tandem double lesions from attack by a charged particle have not been reported
Optical precursors in transparent media
We theoretically study the linear propagation of a stepwise pulse through a
dilute dispersive medium when the frequency of the optical carrier coincides
with the center of a natural or electromagnetically induced transparency window
of the medium (slow-light systems). We obtain fully analytical expressions of
the entirety of the step response and show that, for parameters representative
of real experiments, Sommerfeld-Brillouin precursors, main field and second
precursors "postcursors" can be distinctly observed, all with amplitudes
comparable to that of the incident step. This behavior strongly contrasts with
that of the systems generally considered up to now
Синтез та антиоксидантні властивості нових тіазоло[4,5-b]піридин-2-онів
Aim. To expand the synthetic potential of thiazolo[4,5-b]pyridines, study the reactivity and perform the pharmacological screening of the antioxidant activity of the novel compounds synthesized.Results and discussion. A series of novel 3-aryl-5-hydroxy-7-methyl-3H-thiazolo[4,5-b]pyridine-2-ones were obtained as a result of the interaction of 3-aryl-4-iminothiazolidine-2-ones with ethyl acetoacetate. At this stage the resulting 3-phenyl-5-hydroxy-7-methyl-3H-thiazolo[4,5-b]pyridin-2-one was modified in position 5 in the acylation reaction. For all compounds synthesized the primary pharmacological screening of the antioxidant activity was performed; the results showed the potential for the search of antioxidant agents among thiazolo[4,5-b]pyridine-2-ones.Experimental part. By the reactions of [3+3]-cyclocondensation and acylation 12 novel thiazolo[4,5-b]pyridine-2-ones were obtained. The structure of all compounds synthesized was confirmed by the method of 1H NMR-spectroscopy and the data of elemental analysis. The antioxidant activity of the compounds synthesized was investigated in vitro by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl radical.Conclusions. 12 novel thiazolo[4,5-b]pyridines have been synthesized, their antioxidant properties have been investigated, and prospectivity for the search of novel antioxidant agents among thiazolo[4,5-b]pyridines has been shown.Цель. Расширение синтетического потенциала тиазоло[4,5-b]пиридинов, исследование реакционной способности и проведение фармакологического скрининга на антиоксидантную активность новых синтезированных соединений.Результаты и обсуждение. В результате взаимодействия 3-арил-4-иминотиазолидин-2-онов с ацетоуксусным эфиром получен ряд новых 3-арил-5-гидрокси-7-метил-3H-тиазоло[4,5-b]пиридин-2-онов. Полученный на данной стадии 3-фенил-5-гидрокси-7-метил-3H-тиазоло[4,5-b]пиридин-2-он модифицирован по положению 5 в реакции ацилирования. Для всех синтезированных соединений проведен первичный фармакологический скрининг антиоксидантной активности; полученные результаты демонстрируют потенциал поиска антиоксидантных агентов среди тиазоло[4,5-b]пиридин-2-онов.Экспериментальная часть. С помощью реакций [3+3]-циклоконденсации и ацилирования получены 12 новых тиазоло[4,5-b]пиридин-2-онов. Структура всех синтезированных соединений подтверждена методом 1Н ЯМР-спектроскопии и данными элементного анализа. Антиоксидантную активность синтезированных соединений исследовали in vitro путем определения уменьшения концентрации свободного радикала 2,2-дифенил-1-пикрилгидразила.Выводы. Синтезированы 12 новых тиазоло[4,5-b]пиридинов, изучена их антиоксидантная активность и показана перспективность поиска новых антиоксидантов в ряду тиазоло[4,5-b]пиридинов.Мета. Розширення синтетичного потенціалу тіазоло[4,5-b]піридинів, дослідження реакційної здатності та проведення фармакологічного скринінгу на антиоксидантну активність нових синтезованих сполук.Результати та обговорення. У результаті взаємодії 3-арил-4-імінотіазолідин-2-онів з ацетооцтовим естером отримано ряд нових 3-арил-5-гідрокси-7-метил-3H-тіазоло[4,5-b]піридин-2-онів. Одержаний на даній стадії 3-феніл-5-гідрокси-7-метил-3H-тіазоло[4,5-b]піридин-2-он модифіковано за положенням 5 у реакції ацилювання. Для усіх синтезованих сполук проведено первинний фармакологічний скринінг антиоксидантної активності; отримані результати демонструють потенціал пошуку антиоксидантних агентів серед тіазоло[4,5-b]піридин-2-онів.Експериментальна частина. За допомогою реакцій [3+3]-циклоконденсації та ацилювання отримано 12 нових тіазоло[4,5-b]піридин-2-онів. Структуру усіх синтезованих сполук підтверджено методом 1Н ЯМР-спектроскопії та даними елементного аналізу. Антиоксидантну активність синтезованих сполук досліджували in vitro шляхом визначення зменшення концентрації вільного радикалу 2,2-дифеніл-1-пікрилгідразилу.Висновки. Синтезовано 12 нових тіазоло[4,5-b]піридин-2-онів, досліджено їх антиоксидантні властивості та показано перспективність пошуку нових антиоксидантів у ряду тіазоло[4,5-b]піридинів
СИНТЕЗ І ДОСЛІДЖЕННЯ АНТИОКСИДАНТНОЇ АКТИВНОСТІ 3-[5-(5,7-ДИМЕТИЛ-2-ОКСО-ТІАЗОЛО[4,5-B]ПІРИДИН-3-ІЛМЕТИЛ)-[1,3,4]ОКСОДІАЗОЛ-2-ІЛСУЛЬФАНІЛ-ПРОПІОНОВОЇ КИСЛОТИ ТА ЇЇ АМІДІВ
The aim of the work. Synthesis of 3-[5-(5,7-dimethyl-2-oxo-thiazolo[4,5-b]pyridin-3-ylmethyl)-[1,3,4]oxodiazol-2-ylsulfanyl]-propionic acid and its amides, as well as prescreening of their antioxidant activity.
Materials and methods. Methods of organic synthesis, NMR spectroscopy, elemental analysis, pharmacological screening.
Results and Discussion. The previously obtained 3-[5-(5,7-dimethyl-2-oxo-thiazolo[4,5-b]pyridin-3-ylmethyl)-[1,3,4]oxodiazol-2-ylsulfanyl]-propionitrile was hydrolyzed resulting in 3-[5-(5,7-dimethyl-2-oxo-thiazolo[4,5-b]pyridin-3-ylmethyl)-[1,3,4]oxodiazol-2-ylsulfanyl]-propionic acid. For the transformation by carboxyl group, the corresponding acid chlorides was obtained, which was utilized in the the reaction of acylation of aromatic amines for obtaining a series of propionamides. For all synthesized compounds, a primary pharmacological screening of antioxidant activity was performed.
Conclusions. As a result of structural modification of 3-[5-(5,7-dimethyl-2-oxo-thiazolo[4,5-b]pyridin-3-ylmethyl)-[1,3,4]oxodiazol-2-ylsulfanyl]-propionitrile a serie of novel thiazolo [4,5-b] pyridines was obtained. The results of primary screening of the antioxidant activity of the synthesized compounds demonstrate the potential for the search for new antioxidant agents among thiazolo[4,5-b]pyridin-2-ones.Мета роботи. Здійснити синтез 3-[5-(5,7-диметил-2-оксо-тіазоло[4,5-b]піридин-3-ілметил)-[1,3,4]оксодіазол-2-ілсульфаніл-пропіонової кислоти та її амідів, а також провести первинний скринінг їх антиоксидантної активності.
Матеріали і методи. Органічний синтез, 1Н ЯМР-спектроскопія, елементний аналіз, фармакологічний скринінг.
Результати й обговорення. Отриманий нами раніше 3-[5-(5,7-диметил-2-оксо-тіазоло[4,5-b]піридин-3-ілметил)-[1,3,4]оксодіазол-2-ілсульфаніл-пропіонітрил піддали гідролізу, що привело до отримання 3-[5-(5,7-диметил-2-оксо-тіазоло[4,5-b]піридин-3-ілметил)-[1,3,4]оксодіазол-2-ілсульфаніл-пропіонової кислоти. Для трансформації за карбоксильною групою зазначеної сполуки одержано відповідний хлорангідрид, який введено у реакції ацилювання ароматичних амінів, що дозволило отримати ряд відповідних пропіонамідів. Для усіх синтезованих сполук проведений первинний скринінг антиоксидантної активності.
Висновки. У результаті структурної модифікації 3-[5-(5,7-диметил-2-оксо-тіазоло[4,5-b]піридин-3-ілметил)-[1,3,4]оксодіазол-2-ілсульфаніл-пропіонітрилу, одержано серію нових тіазоло[4,5-b]піридинів. Отримані результати первинного скринінгу антиоксидантної активності синтезованих сполук демонструють потенціал для пошуку антиоксидантних агентів серед тіазоло[4,5-b]піридин-2-онів
Law Enforcement as Discretion and Legal Process
This article investigates the analytical and synthesis aspects of a wide range of sources, considering law enforcement from a dual perspective: as legal discretion and as a kind of legal process. This research applied the classical methodology of qualitative analysis of systems and processes, in particular, a system-analytical approach to the study of research object
Additive Laser Excitation of Giant Nonlinear Surface Acoustic Wave Pulses
The laser ultrasonics technique perfectly fits the needs for non-contact,
non-invasive, non-destructive mechanical probing of samples of mm to nm sizes.
This technique is however limited to the excitation of low-amplitude strains,
below the threshold for optical damage of the sample. In the context of strain
engineering of materials, alternative optical techniques enabling the
excitation of high amplitude strains in a non-destructive optical regime are
seeking. We introduce here a non-destructive method for laser-shock wave
generation based on additive superposition of multiple laser-excited strain
waves. This technique enables strain generation up to mechanical failure of a
sample at pump laser fluences below optical ablation or melting thresholds. We
demonstrate the ability to generate nonlinear surface acoustic waves (SAWs) in
Nb:SrTiO substrates, at typically 1 kHz repetition rate, with associated
strains in the percent range and pressures close to 100 kbars. This study paves
the way for the investigation of a host of high-strength SAW-induced phenomena,
including phase transitions in conventional and quantum materials, plasticity
and a myriad of material failure modes, chemistry and other effects in bulk
samples, thin layers, or two-dimensional materials
Anticorrosion Protection by Amine-Ionic Liquid Mixtures: Experiments and Simulations
The mixtures of aqueous amines and ionic liquids (ILs) are considered as potential solvents for CO2 capture. We report corrosion and CO2 absorption behavior of the mixed IL-amine solutions. The absorption tests were performed at 318.15 K under 0.1-2.7 MPa. The corrosion tests were carried out at 318.15 K under 2.7 MPa. Addition of [bmim][BF4] in aqueous alkanolamine solutions reduces corrosion rate for MEA by up to 72%. The CO, absorption capacity in the mixtures falls between those of aqueous MDEA and pure IL. These results allow to choose the working pressure range as a function of other parameters, such as gas pressure and mixture viscosity. According to the simulations, [bmim][BF4] participates in the gas capture through H-bonding, although the number of amine molecules is enough to capture all supplied CO, molecules. The equilibrium of the chemisorption reaction is, therefore, modified upon the stepwise IL addition. An ideal IL content for preventing corrosion is 10% w/w.CNPqHewlett-Packard Brasil LtdaCAPESPontif Catholic Univ Rio Grande Sul PUCRS, Postgrad Program Mat Engn & Technol, Ave Ipiranga 6681, BR-90619900 Porto Alegre, RS, BrazilPontif Catholic Univ Rio Grande Sul PUCRS, Sch Chem, Ave Ipiranga 6681, BR-90619900 Porto Alegre, RS, BrazilPontif Catholic Univ Rio Grande Sul PUCRS, Sch Engn, Ave Ipiranga 6681, BR-90619900 Porto Alegre, RS, BrazilUniv Fed Sao Paulo, BR-04021001 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, BR-04021001 Sao Paulo, SP, BrazilWeb of Scienc
Interpolated wave functions for nonadiabatic simulations with the fixed-node quantum Monte Carlo method
Simulating nonadiabatic effects with many-body wave function approaches is an
open field with many challenges. Recent interest has been driven by new
algorithmic developments and improved theoretical understanding of properties
unique to electron-ion wave functions. Fixed-node diffusion Monte Caro is one
technique that has shown promising results for simulating electron-ion systems.
In particular, we focus on the CH molecule for which previous results suggested
a relatively significant contribution to the energy from nonadiabatic effects.
We propose a new wave function ansatz for diatomic systems which involves
interpolating the determinant coefficients calculated from configuration
interaction methods. We find this to be an improvement beyond previous wave
function forms that have been considered. The calculated nonadiabatic
contribution to the energy in the CH molecule is reduced compared to our
previous results, but still remains the largest among the molecules under
consideration.Comment: 7 pages, 3 figure
- …