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Wyświetlanie 1-15 z 82
Tytuł:
Can urea breath test (UBT) replace rapid urea test (RUT)?
Autorzy:
Nawacki, Łukasz
Czyż, Agata
Bryk, Piotr
Kozieł, Dorota
Stępień, Renata
Głuszek, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/1392890.pdf
Data publikacji:
2018
Wydawca:
Index Copernicus International
Tematy:
Helicobacter pylori
urea breath test
rapid urea test
gastric cancer
Opis:
Background: Helicobacter pylori (Hp) is classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen. Its influence on the carcinogenesis of gastric cancer has been confirmed in many research studies. The conclusion is obvious - early detection and eradication of Hp can prevent the development of the disease. Methods: The objective of the study was to analyze the clinical and practical value of Carbon-13 urea breath test (UBT) in patients hospitalized due to pain complaints in the upper abdomen and dyspeptic symptoms. Fifty patients were enrolled in the study. Each patient underwent urea breath test according to the instruction included by the producer. Thereafter, each patient included in the study group was subjected to endoscopy of the upper gastrointestinal tract with the biopsy of the mucosa to determine the urease activity with rapid urease test (RUT). Results: In the study group, 14 patients (28%) achieved a positive urease test result which was confirmed in RUT. Four (8%) patients, despite a positive breath test, did not have a positive result in urease activity test from gastric mucosa. In 2 cases (4%) despite negative result of UBT, urease activity was confirmed in gastroscopic sections. The remaining 30 patients (60%) had a negative result in both studies. Conclusions: The limited availability of the gold standard for diagnostics of upper gastrointestinal tract diseases (gastroscopy) is the basis for the search for new methods of detection of Helicobacter pylori infections. The urea breath test is a method of high sensitivity and specificity. The positive result of urea breath test may be the basis for inclusion of eradication therapy.
Źródło:
Polish Journal of Surgery; 2018, 90, 5; 44-48
0032-373X
2299-2847
Pojawia się w:
Polish Journal of Surgery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Obtaining of urea-modified starches and their properties
Otrzymywanie i właściwości skrobi modyfikowanych z udziałem mocznika
Autorzy:
Sroczyński, A.
Iwanowski, W.
Nebesny, E.
Powiązania:
https://bibliotekanauki.pl/articles/1396405.pdf
Data publikacji:
1985
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
urea-modified starch
Opis:
Starch was modified with the use of urea in presences of magnesium sulphate and sulphuric acid or phosphoric acid. The influence of various factors on the physico-chemical properties of modified starch was examined.
Skrobię ziemniaczaną mieszano w podwyższonej temperaturze z roztworem wodnym zawierającym kwas siarkowy, siarczan magnezowy i mocznik, po czym mieszaninę reakcyjną suszono i prażono w temp. 125°C (398 K). W poszczególnych doświadczeniach zmieniano kolejno czas prażenia oraz dawki kwasu siarkowego, mocznika i siarczanu magnezowego. W dalszych badaniach zastępowano również siarczan magnezowy innymi solami, a kwas siarkowy wymieniano na kwas fosforowy, Uzyskano interesujące wyniki wpływu rodzaju i ilości wprowadzanych chemikaliów na lepkość kleików i redukcyjność otrzymanych preparatów modyfikowanej skrobi. Rezultaty doświadczeń pośrednio wskazują na sieciowanie skrobi z udziałem doświadczeń pośrednio wskazują na sieciowanie skrobi z udziałem mocznika nie tylko za pomocą wiązań cząsteczek przy węglu C₁, ale również za pomocą poprzecznych wiązań, np. przy węglach C₆. Te ostatnie wiązania poprzeczne powstają również za pośrednictwem reszt fosforanowych.
Źródło:
Acta Alimentaria Polonica; 1985, 11, 1; 3-10
0137-1495
Pojawia się w:
Acta Alimentaria Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of serum creatinine, urea, and aminotransferase levels among methamphetamine addicted individuals in Khartoum State
Autorzy:
Al-Tayeb, Al-Noor Opied
Abubakr, Mohammed Hayati
Elrheima, Hafsa Ahmed
Habbani, Ahmed Khalid
Elrasul, Rami Y. Hassab
Powiązania:
https://bibliotekanauki.pl/articles/38695722.pdf
Data publikacji:
2024-03-30
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
aminotransferases
creatinine
methamphetamine
urea
Opis:
Introduction and aim. Methamphetamine-use disorder is a pressing global public health issue. In Sudan, the escalating methamphetamine (METH) consumption has become a significant social and health problem. This study aims to evaluate liver and kidney biomarkers in methamphetamine addicts in Khartoum state. Material and methods. The study was an analytical prospective cross-sectional hospital-based study. One hundred participants were enrolled in this study, fifty were cases (methamphetamine addicts), and others were healthy non-METH users as a comparative group. Results. METH users had a mean age of (27±7) years and had been using METH for an average of (14±9) months. Urea and creatinine levels were also significantly elevated in METH users compared to non-users, with p<0.001 and p=0.044, respectively. Their aspartate transaminase (AST) and alanine transaminase (ALT) levels were significantly higher compared to non-users, with p<0.001. Conclusion. There was significant increases in creatinine, urea, and aminotransferases levels in the case group. ALT showed a moderate positive correlation with abuse duration, while AST showed no significant correlation. Urea and creatinine levels had strong and moderate positive correlations with abuse duration, respectively.
Źródło:
European Journal of Clinical and Experimental Medicine; 2024, 22, 1; 68-72
2544-2406
2544-1361
Pojawia się w:
European Journal of Clinical and Experimental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical evaluation of urea-mixing devices for close-coupled selective catalytic reduction systems
Autorzy:
Kaźmierski, Bartosz Grzegorz
Kapusta, Łukasz Jan
Powiązania:
https://bibliotekanauki.pl/articles/24202462.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
urea water solution
urea mixer
selective catalytic reduction
SCR
roztwór mocznika
mieszalnik mocznika
selektywna redukcja katalityczna
Opis:
The following research presents a numerical evaluation of existing and conceptual urea-mixing devices used in close-coupled (to the engine) selective catalytic reduction (SCR) systems. The analysis was aimed at the assessment of urea-mixing devices that could considerably enhance the reduction of nitrogen oxides from the diesel-engine combustion process under a wide range of operating conditions, including cold starts. The analysis showed that replacing blade-equipped static mixers with perforated stationary mixing devices may provide a more uniform spatial distribution of ammonia at the inlet to the SCR catalyst and reduce pressure drops generated by mixing devices. Moreover, the conceptual mixing devices, based on combinations of the blade and perforated mixers to develop intensive turbulence, enabled the increase of the mixing length leading to effective decomposition of the urea-water solution (UWS), and provided uniform spatial distribution of ammonia, even for the small-sized mixing systems. However, the intensive mixing was often associated with a significant rise in the pressure drop.
Źródło:
Combustion Engines; 2023, 62, 2; 84--93
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of urea and formaldehyde on enzymatic hydrolysis of cellulose
Autorzy:
Marchwicka, Monika
Lesiak, Anna
Radomski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2200202.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
enzymatic hydrolysis of cellulose
inhibitors
urea
formaldehyde
Opis:
Effect of selected urea and formaldehyde concentrations on glucose yield of enzymatic hydrolysis of cellulose was investigated. Urea and formaldehyde were added separately at the concentrations of 0.001, 0.002 and 0.005 g/cm3. Glucose was determined by high-performance liquid chromatography (HPLC). It was found that the used concentrations of urea didn’t influence glucose yield. In the case of formaldehyde, the results vary between used concentrations. The glucose yield of enzymatic hydrolysis of cellulose with the highest investigated concentration of formaldehyde (0.005 g/cm3) decreased by 50 %.
Wpływ mocznika i formaldehydu na hydrolizę enzymatyczną celulozy. Prezentowane badania miały na celu określenie wpływu wybranych dodatków mocznika i formaldehydu na wydajność glukozy w enzymatycznej hydrolizie celulozy. Mocznik oraz formaldehyd dodano osobno w stężeniach 0,001, 0,002 i 0,005 g/cm3. Wydajność glukozy po hydrolizie enzymatycznej oznaczano za pomocą wysokosprawnej chromatografii cieczowej (HPLC). Stwierdzono, że zastosowane stężenia mocznika nie miały wpływu na wydajność glukozy. W przypadku formaldehydu wyniki różnią się między zastosowanymi stężeniami. Wydajność glukozy hydrolizy enzymatycznej celulozy z największym badanym stężeniem formaldehydu (0,005 g/cm3) była prawie o połowę mniejsza w porównaniu do hydrolizy enzymatycznej celulozy bez formaldehydu.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2020, 110; 92--96
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The concentration of urea in hemolymph as a marker of health in Lissachatina fulica and Cornu aspersum edible snails – a preliminary study
Autorzy:
Ziętek, J.
Guz, L.
Wójcik, A.
Winiarczyk, S.
Adaszek, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/2087559.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Lissachatina fulica
Cornu aspersum
hemolymph
urea
markers
Źródło:
Polish Journal of Veterinary Sciences; 2019, 2; 259-262
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effectiveness of the use of urease inhibitors in agriculture: a review
Autorzy:
Matczuk, D.
Siczek, A.
Powiązania:
https://bibliotekanauki.pl/articles/2083072.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
soil urease
urea
urease inhibitors
ammonia
volatilization
Opis:
Urea is one of the most popular fertilizers in the world. In 2018, the global production capacity of urea reached the level of 210 million metric tonnes. Due to the fact that the world population is growing steadily, the demand for food is increasing, and thus also the consumption of urea. The use of urea-based fertilizers has negative consequences in the form of ammonia volatilization. The solution to this problem may be the use of urease inhibitors. Currently, inhibitors of synthetic origin are available on the market, while the use of inhibitors of natural origin is still being under trial. The use of the most commonly used urease inhibitor – NBPT together with urea causes a reduction in ammonia emissions and has a beneficial effect on crop productivity. At the same time, the search for inhibitors of natural origin is underway, which, apart from reducing ammonia volatilization into the atmosphere, could have a positive effect on crop yields. In this paper, recent advances in this field are reviewed.
Źródło:
International Agrophysics; 2021, 35, 2; 197-208
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plant ureases: Roles and regulation.
Autorzy:
Sirko, Agnieszka
Brodzik, Robert
Powiązania:
https://bibliotekanauki.pl/articles/1044275.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
urea
plants
nickel
urease activity
nitrogen metabolism
Opis:
Both urea and urease were subjects of early scientific investigations. Urea was the first organic molecule to be synthesized and jack bean urease was the first enzyme ever to be crystallized. About 50 years later it was shown to be the first nickel metalloenzyme. Since then, nickel-dependent ureases have been isolated from many bacteria, fungi and higher plants. They have similar structures and mechanisms of catalysis. A urease apoenzyme needs to be activated. This process requires participation of several accessory proteins that incorporate nickel into the urease forming catalytic site. In this review, ureases from various organisms are briefly described and the similarities of their structures discussed. Moreover, the significance of urea recycling in plants is explained and recent literature data about the function and activation of plant ureases are presented.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 1189-1195
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibitors of bacterial and plants urease. A review
Autorzy:
Macegoniuk, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/764860.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
urea
urease
inhibitor
ulcer disease
kidney stones
Opis:
Urease is an important virulence factor for Helicobacter pylori and Proteus mirabilis as well as in environmental transformations of certain nitrogenous compounds. Urea hydrolysis caused by these microorganisms leads to increased pH and ammonia toxicity and enables bacterial colonization of the human gastric mucosa and urinary tract formation of struvite and carbonate-apatite stones. Due to the possibility of medical applications the development of novel, selective and efficient classes of urease inhibitors which satisfy the low toxicity requirement for human health and have low environmental impact is necessary. In this article are described the various urease inhibitors used so far by researchers, especially in the last few years.
Źródło:
Acta Universitatis Lodziensis. Folia Biologica et Oecologica; 2013, 9; 9-16
1730-2366
2083-8484
Pojawia się w:
Acta Universitatis Lodziensis. Folia Biologica et Oecologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Precipitation of calcium carbonate in the presence of urea at 293 K and 343 K
Autorzy:
Białowicz, K.
Kiełkowska, U.
Powiązania:
https://bibliotekanauki.pl/articles/778787.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
calcium carbonate
precipitation
sodium bicarbonate
urea
utilization
Opis:
The results of the precipitation of calcium carbonate from a waste post-distillation liquid (DS) and a sodium bicarbonate saturated solution – both from the Solvay method – in the presence of urea are presented. The investigation was carried out at 293 K and 343 K. Reagent dosage times of 1, 5, 10, 20 and 30 min, and urea concentrations of 5, 6 and 10 mol/dm3 were applied. The granulometric composition, the values of bulk and packing densities and the absorptiveness sorption of water and paraffin oil from the obtained calcium carbonate were investigated.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 2; 95-98
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remarks on spectra-photometric monitoring of urea in dialysate
Autorzy:
Filutowicz, Z.
Łukaszewski, K.
Pieszyński, K.
Powiązania:
https://bibliotekanauki.pl/articles/333345.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
monitorowanie dializ
mocznik
spektrofotometria
dialysis monitoring
urea
spectrophotometry
Opis:
The authors try to explain why the direct, spectra-photometric examination of urea content in dialysate is practically ineffective (in UV-VIS range of spectrum) despite the fact that, in general, spectra-photometry is valuable and very sensitive method of chemical composition determination. An attempt was made to prove that spectra-photometric monitoring of urea dialysis, in chosen parts of UV-VIS spectrum, can be achieved only through indirect measurements.
Źródło:
Journal of Medical Informatics & Technologies; 2004, 8; MM105-110
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conformational destabilization of Bacillus licheniformis α-amylase induced by lysine modification and calcium depletion
Autorzy:
Tan, Cheau
Rahman, Raja
Kadir, Habsah
Tayyab, Saad
Powiązania:
https://bibliotekanauki.pl/articles/1039896.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
salt bridges
urea
BLA
calcium
lysine
stability
conformation
Opis:
Bacillus licheniformis α-amylase (BLA) was chemically modified using 100-fold molar excess of succinic anhydride over protein or 0.66 M potassium cyanate to obtain 42 % succinylated and 81 % carbamylated BLAs. Size and charge homogeneity of modified preparations was established by Sephacryl S-200 HR gel chromatography and polyacrylamide gel electrophoresis. Conformational alteration in these preparations was evident by the larger Stokes radii (3.40 nm for carbamylated and 3.34 nm for succinylated BLAs) compared to 2.43 nm obtained for native BLA. Urea denaturation results using mean residue ellipticity (MRE) as a probe also showed conformational destabilization based on the early start of transition as well as ΔGDH2O values obtained for both modified derivatives and Ca-depleted BLA. Decrease in ΔGDH2O value from 5,930 cal/mol (for native BLA) to 3,957 cal/mol (for succinylated BLA), 3,336 cal/mol (for carbamylated BLA) and 3,430 cal/mol for Ca-depleted BLA suggested reduced conformational stability upon modification of amino groups of BLA or depletion of calcium. Since both succinylation and carbamylation reactions abolish the positive charge on amino groups (both α- and ε- amino), the decrease in conformational stability can be ascribed to the disruption of salt bridges present in the protein which might have released the intrinsic calcium from its binding site.
Źródło:
Acta Biochimica Polonica; 2011, 58, 3; 405-412
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distribution of dissolved amino acids, dissolved saccharides and urea in the southern Drake Passage and the Bransfield Strait during BIOMASS-FIBEX, 1981
Autorzy:
Mężykowski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2057640.pdf
Data publikacji:
1982
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Antarctica
FIBEX
dissolved amino acids
dissolved saccharides
urea
Źródło:
Polish Polar Research; 1982, 3, 3-4; 171-182
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of the back pressure influence on urea-water-solution mixing performance in close coupled SCR system
Autorzy:
Rogóż, R.
Bachanek, J.
Boruc, Ł.
Teodorczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/245838.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
SCR
urea water solution
uniformity
CFD
back pressure
Opis:
The upcoming Euro 6d emission standard puts more even stringent requirements for diesel engine cars, especially in the case of nitrogen oxides (NOx) emission. The most widely used technique to meet tight standards is Selective Catalytic Reduction (SCR) with urea-water-solution (UWS) injection. One of the crucial factors is even ammonia distribution at the catalyst inlet; hence, very often product development is focused around this issue. The product development is supported by both experimental and numerical work. The common approach to measure cross section ammonia distribution on the SCR is using sampling system at catalyst outlet. Very often exhaust layout is opened just after the SCR catalyst, cutting off the rest part for instance tailpipe or Clean-up Catalyst. Therefore, a backpressure at SCR outlet resulting from the downstream part is also eliminated. This could significantly affect flow parameters as the density changes, thus ammonia distribution and wall film deposition may vary as well. Within this work, the influence of the backpressure at SCR outlet on the ammonia distribution and wall wetting was numerically investigated. The simulations were run under various boundary conditions for the Close Coupled SCR architecture. It was shown that depending on the operating point the boundary pressure affects both factors on the different level.
Źródło:
Journal of KONES; 2018, 25, 3; 377-383
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solid-State Mechanochemical Synthesis of Kaolinite-Urea Complexes for Application as Slow Release Fertilizer
Autorzy:
AlShamaileh, Ehab M.
Al-Rawajfeh, Aiman E.
Alrbaihat, Mohammad R.
Powiązania:
https://bibliotekanauki.pl/articles/123521.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
mechano-chemical
ball milling
slow release
kaolinite
urea
Opis:
This study investigated a mechanochemical (MC) process for synthesizing a slow-release urea fertilizer by cogrinding the starting materials of (NH2)2CO and amorphous kaolinite in a planetary ball mill. The tests with kaolinite contents ranging from 25 to 75 wt. %, milling time ranging from 1 (h) to 3 (h) and mill rotational speeds from 200 to 700 rpm were performed to evaluate the incorporation of (NH2)2CO and release of nitrogen into the solution. The analyses conducted using XRD, TGA, FT-IR and KNDU (Kjeldahl Nitrogen Determination Unit) indicated that the MC process was successfully applied to incorporate (NH2)2CO into the amorphous kaolinite structure. The release of nitrogen from the system (kaolinite-(NH2)2CO) when dispersed in water for 24 h reached up to 20% at 25% wt of kaolinite. Moreover, under the milling speed conditions for the system (kaolinite–(NH2)2CO), release of nitrogen reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolinite to act as a carrier of nitrogen nutrients to be released slowly for use as fertilizer.
Źródło:
Journal of Ecological Engineering; 2019, 20, 9; 267-276
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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