Wyniki wyszukiwania - BazTech

1

Enhancement of the corrosion resistance for stainless steel 316 by applying laser shock peening

Jasim Sarah A., Ayesh Ammar, Kadhim A., Abdullah Oday I.

Polish Journal of Chemical Technology

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2024

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Vol. 26, nr 1

1--7

EN

This research paper focuses on enhancing the surface characteristics of the 316 stainless steel (SS316) alloy, including roughness, microhardness, and corrosion resistance. Where the application of ND-YAG laser technology, a highly relevant and timely area, was investigated deeply. The Q-switching Nd: YAG Laser was used with varying laser energy levels within the context of the laser shock peening (LSP) technique. The corrosion resistance of the 316 ss alloy is evaluated in a corrosive environment of 500 mL of saliva (with a pH of 5.6) through electrochemical corrosion testing. Corrosion rate was determined based on the analysis of polarization curves. The outcomes of this research reveal that as the laser energy was increased, there was a noticeable enhancement in the mechanical properties of the 316 ss alloy’s surface. Importantly, the corrosion rate experiences a significant reduction, decreasing from 4.94 mm/yr to 3.59 mm/yr following laser shock peening (LSP) application.

2

Potencjał diagnostyczny śliny w kontekście oznaczania aminokwasów tiolowych i ich związku z chorobami

Stachniuk J., Furmaniak P., Głowacki R.

Analityka : nauka i praktyka

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2016

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nr 1

64--68

PL

Ślina stanowi doskonałą alternatywę dla osocza, gdyż pobierana w nieinwazyjny sposób przez osoby bez specjalistycznego przeszkolenia może być wiarygodnym źródłem cennych informacji.

3

Zastosowanie metody FT-IRM w badaniach adsorpcji mucyny na powierzchni wybranych biomateriałów

Mystkowska J., Kolmas J., Dąbrowski J. R.

Engineering of Biomaterials

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2011

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Vol. 14, no. 106-108

85--88

PL

W pracy przedstawiono wyniki badań adsorpcji mucyny zwierzęcej na powierzchni wybranych biomateriałów. Przebadano po dwie próbki każdego z materiałów, których powierzchnie różniły się chropowatością. Badania przeprowadzono za pomocą mikrospektroskopii w podczerwieni z transformacją Fouriera (FT-IRM). Wyniki badań wskazują na adsorpcję mucyny do wszystkich testowanych materiałów. Zaobserwowano wpływ rodzaju biomateriału na intensywność adsorpcji testowanej proteiny do jego powierzchni.

EN

This work presents results of research of animal mucin adsorption on the surface of selected biomaterials. Two samples of each material with different surface roughness were investigated. The tests were performed using Fourier-transform infrared microspectroscopy (FT-IRM). The results indicate that mucin adsorb to all tested materials surface. The influence of biomaterial type on protein adsorption intensity to material surface was observed.

4

Charakterystyka stateryny - białka śliny zaangażowanego w utrzymywanie homeostazy jamy ustnej

Jackiewicz-Barańska D., Kamysz E., Maćkiewicz Z.

Wiadomości Chemiczne

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2008

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[Z] 62, 7-8

595-608

EN

Saliva is a gel resembling liquid, that acts almost as an organic tissue [1]. Saliva influences oral health through its non-specific physico-chemical properties [2]. It is composed of secretions from parotid, submandibular and sublingual glands, and smaller contributions come from minor salivary glands (e.g. palatal and labial). Saliva contains a number of proteins and polypeptides [2]. One of them is statherin a multifunctional 43-amino acid residue phosphominiprotein, containing vicinal phosphoserines at 2 and 3 positions and seven residues of tyrosine (Fig. 1) [7]. The relevant structural feature of statherin is N-terminal helix segment connected to a long poly--L-proline type II segment, which is followed by a short extended structure [14]. The gene for statherin is believed to be a single-copy gene and has been mapped to human chromosome 4q11-13 [20]. The statherin variants are SV1, SV2 and SV3 which comprise approx. 30% of the statherin family (Fig. 6). The ratios of statherin : SV1 and SV2 : SV3 are in both cases approx. 3 : 1. Statherin and SV2 are products of two different transcripts found in each of the major salivary gland. The variants SV1 and SV3 are derived by post-translational processing of statherin and SV2 [22]. Statherin is a multifunctional molecule that shows a high affinity for calcium phosphate minerals such as hydroxyapatite. It takes part in the calcium and phosphate transport during secretion in the salivary glands, is responsible for the protection and recalcification of tooth enamel, promotes selective initial bacterial colonization of enamel, and functions as a boundary lubricant on the enamel surface [38, 39]. Satherin levels of concentration in saliva could be in relation with the precancerous and cancerous lesions of the oral cavity [38]. The understanding of a profile and role of statherin has become important in medicine as the peptide could play a protective effect in oral cavity. However, the role and the functions of this peptide are still not well-know [38].

5

Influence of surface modification on friction coefficient of the titanium–elastomer couple

Chladek W., Hadasik E., Chladek G.

Acta of Bioengineering and Biomechanics

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2007

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Vol. 9, nr 2

17-25

EN

This paper presents the results of a study of the friction coefficient of titanium–elastomer couple. The study was carried out with a view to potential future utilization of its results for constructing retentive elements of implanted prostheses. Changes in the friction force were recorded while removing titanium specimens placed between two silicone counter specimens made of Ufi Gel. The influence of the titanium specimen movement speed in relation that of to the counter specimens and the influence of clamping force on the friction force were assessed. Additionally, the surface roughness of titanium specimens differed; in one case, titanium was coated with polyethylene. The effect of introducing artificial saliva between the cooperating surfaces on the friction force and friction coefficient was analyzed as well. Based on the characteristics recorded, the possibilities of shaping the friction coefficient have been assessed, since it is the friction coefficient that determines effective operation of a friction couple through increasing the titanium specimen roughness. The artificial saliva being introduced between the specimens reduces considerably the friction coefficient through a change of the phenomenon model. An increase in the pressure force for the specimens of high roughness entails a reduction of the friction coefficient. The study carried out allows us to identify the roughness parameters, which in turn will enable obtaining the prescribed retention force for friction/membrane couplings.

6

HPLC method for the determination of methotrexate and 7-hydroxymethotrexate in children with acute lymphoblastic leukemia

Skibińska Ł., Gregorczyk J.

Chemia Analityczna

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2001

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Vol. 46, No. 3

329-336

EN

A sensitive high-performance liquid chromatographic method for simultaneous determination of methotrexate and its main metabolite 7-hydroxymethotrexate in serum and saliva is reported. The method involved solid phase extraction on Bakerbond SPE Cm cartridges. The percentage recovery from both biological fluids was 87 and 80% for methotrexate and 7-hydroxymethotrexate. The samples were chromatographed on a LiChrospherRP-18 column using phosphate buffer at pH 5.75 (84%), methanol (11%) and acetonitrile (5%) as a mobile phase. The effluent from the column was monitored at 305 nm./7-Aminoacetophenone was used as an internal standard. The method is selective and reproducible. The limit of detection for the determination of methotrexate and its metabolite in serum and saliva was 5 ng ml(-1), whereas the limit of quantitation was 25 ng ml(-1) for both compounds.

PL

Zastosowano .czułą, selektywną i precyzyjną metodę HPLC oznaczania obok siebie metotreksatu i jego głównego metabolitu 7-hydroksymetotreksatu w surowicy i ślinie pacjentów. Analizę chromatograficzną poprzedzono ekstrakcją leku i metabolitu na fazie stałej wykorzystując kolumny Bakerbond SPE Cis. Rozdział chromatograficzny przeprowadzono na kolumnie RP-18 stosując detektor spektrofotometryczny przy długości fali Lamda = 305 nm. Fazę ruchomą stanowiła mieszanina buforu fosforanowego o pH 5,75, metanolu! acetonitrylu(84:11:5 v/v). Zastosowano p-aminoacetofenon jako wzorzec wewnętrzny. Odzysk metotreksatu i jego metabolitu z płynu biologicznego był równy odpowiednio 87 i 80%. Granica wykrywalności obu substancji wynosiła 5 ngmP1 a granica oznaczalności 25 ng ml(-1).

7

Determination of morphine and codeine in serum and saliva by gas chromatography-mass spectrometry

Janowska E., Piekoszewski W.

Chemia Analityczna

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2001

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Vol. 46, No. 6

857-864

EN

The GC-MS method of morphine and codeine determination in serum and saliva was developed and validated. The sample preparation consists of enzymatic hydrolysis, deprotei-nisation, solid phase extraction and derivatisation. As the intrinsic standards D3-morphine and D3-codeine were used. Detection limit for morphine and codeine was 4 and 5 ng ml(-1); quantification limit was 14 and 15 ng ml(-1) respectively. The range of quantification was 20-1000 ng ml"1 and the recovery ranged 50-60%. For checking the applicability of the elaborated method, morphine and codeine concentrations were measured in serum and saliva samples taken from 10 addicts. The method allowed to measure morphine in saliva and may be used for monitoring taking home made heroin and detoxification process.

PL

Przedstawiono metodę oznaczania morfiny i kodeiny w surowicy krwi oraz w ślinie za pomocą chromatografii gazowej sprzężonej ze spektrometrią mas. Ekstrakcję analitów, po wcześniejszej hydrolizie enzymatycznej, prowadzono w układzie ciecz-ciało stałe. Morfinę i kodeinę oznaczano, po derywatyzacji te(trimetylosililo)trifluoracetamidem, metodą GC-MS stosując jako substancje wzorcowe związki deuterowane. Wykrywalność metody wynosiła 4 i 5 ng ml'1 a oznaczalność 14 i 15 ng ml'1 odpowiednio dla morfiny i kodeiny. Wydajność ekstrakcji badanych związków wahała się od 50-60%. Opracowaną metodę zastosowano do pomiaru stężenia morfiny i kodeiny u 10 osób uzależnionych od pochodnych alkaloidów opium ("kompotu").