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1.
Materials (Basel) ; 13(24)2020 Dec 19.
Article in English | MEDLINE | ID: mdl-33352815

ABSTRACT

This study deals with metalworking fluids (MWFs). According to DIN 51385, depending on their base, the fluids are divided into oil and water fluids. The oil bases include, among others, mineral, synthetic, vegetable and paraffin oils. This division does not comprise surfactant solutions which can be successfully used in metalworking. Due to the fact that this type of fluid was not qualified, a new type of lubricant based on the aqueous solutions of surfactants has been proposed. Two new notions have been introduced: surfactant working fluids (SWFs) for working fluids and surfactant lubricants (SLs) for all kinds of lubricants as a broader term. The effect of the physicochemical properties of aqueous solutions of sodium lauroyl sarcosinate (SLS), also known as sodium N-dodecanoyl-N-methyl glycinate, on tribological properties determined using a four-ball machine (Tester T-02) (Lukasiewicz Research Network-The Institute for Sustainable Technologies, Radom, Poland) was analyzed. On the basis of aqueous SLS solutions a composition of working fluids was developed and their functional properties were verified by means of tribological and stand tests as well as during operation. The test results obtained clearly indicate that functional properties of 2% solutions of sodium lauroyl sarcosinate with a foam inhibitor (0.05%) and a biocide (0.1%) are comparable to those of a quality commercial hydraulic fluid.

2.
J Surfactants Deterg ; 16(3): 369-375, 2013 May.
Article in English | MEDLINE | ID: mdl-23606804

ABSTRACT

Water can be used as an ecological lubricant base if it is possible to select additives which can beneficially modify its tribological and corrosion properties. Additionally, those additives should not be harmful to human health and the natural environment. These conditions limit or even eliminate the possibility for the application of the additives used in traditional oil bases as they are insoluble in water and often toxic. Alkyl polyglucosides (APGs) have been suggested as additives improving lubricating properties of water. They are biodegradable and do not have to be recycled. They exhibit surface activity. They produce micelles at low concentration and lyotropic liquid crystals at high concentration. Two types of alkyl polyglucosides differing in alkyl chain lengths and degrees of polymerization were used in this investigation. Tribological tests were carried out using a ball-on-disc T-11 tester. The balls were made of steel, whereas the discs were made of steel, aluminium oxide, zirconium oxide, polyamide and poly(methyl methacrylate). The description of the device and the methods has been given in the literature (Szczerek and Tuszynski in TriboTest 8:273-284, 2002). The addition of APGs improves the lubricating properties of water. The relative decrease in motion resistance and wear depends both on the type of friction couple and on the kind of alkyl polyglucoside used. The tribological test results obtained were correlated with the activity of APGs measured as wettability of friction couples by their solutions.

3.
Int J Mol Sci ; 11(1): 189-205, 2010 Jan 12.
Article in English | MEDLINE | ID: mdl-20162010

ABSTRACT

Aqueous solutions of ethoxylated alcohols which form lyotropic liquid crystals at high concentrations (40-80%) were selected as model lubricating substances. Microscopic studies under polarized light and viscosity measurements were carried out in order to confirm the presence of liquid crystalline structures in the case of alcohol solutions with ethoxylation degrees of 3, 5, 7 and 10. Microscopic images and viscosity coefficient values characteristic of various mesophases were obtained. As expected, the viscosity of LLCs decreases considerably with an increase in shearing rate which is characteristic of liquid crystals being non-Newtonian liquids. Antiseizure properties were determined by means of a four-ball machine (T-02 Tester) and characterized by scuffing load (P(t)), seizure load (P(oz)) and limiting pressure of seizure (p(oz)). Alcohol ethoxylates forming mesophases in aqueous solutions have the strongest effect on the P(t) values which are several times higher than those measured in the presence of water. Ethoxylates with higher degrees of ethoxylation exhibit higher values of scuffing load. Those changes have been interpreted as a result of higher cloud points at which those compounds lose their amphiphilic properties. In general, the presence of mesophases in the bulk phase and particularly in the surface phase may lead to the formation of a lubricant film which separates the frictionally cooperating elements of a friction pair. The antiseizure efficiency of alcohol solutions is highest up to the load value which does not exceed the scuffing load value.


Subject(s)
Alcohols/chemistry , Liquid Crystals/chemistry , Solutions/chemistry , Ethylene Oxide/chemistry , Viscosity
4.
Pol Arch Med Wewn ; 119(10): 677-9, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19847146

ABSTRACT

A 45-year-old woman was admitted to the hospital because of abdominal pain, fever, and weight loss. Laboratory tests performed on admission revealed raised inflammatory markers. Ultrasonography of the abdomen showed dilatation of the pyelocalyceal system of the left kidney, while computed tomography showed retroperitoneal concentric periaortic mass extending to common iliac arteries and entrapping the left ureter. We established the diagnosis of idiopathic retroperitoneal fibrosis (RPF). JJ catheter was placed in the left ureter, and treatment with corticosteroids and azathioprine was started. Follow-up examinations showed a gradual improvement, namely a progressive remission of the retroperitoneal mass and normalization of both erythrocyte sedimentation rate and C-reactive protein concentration. Case reports, including our paper, and small case series showed azathioprine to be particularly effective in the treatment of RPF.


Subject(s)
Azathioprine/therapeutic use , Immunosuppressive Agents/therapeutic use , Retroperitoneal Fibrosis/diagnosis , Retroperitoneal Fibrosis/drug therapy , Female , Humans , Middle Aged , Treatment Outcome
5.
Pol Merkur Lekarski ; 22(132): 547-50, 2007 Jun.
Article in Polish | MEDLINE | ID: mdl-17874627

ABSTRACT

UNLABELLED: Leflunomide is a relatively new disease modifying antirheumatic drug (DMARD) and a number of studies evaluating its effectiveness and safety in daily medical practice is limited. THE AIM OF THE STUDY: Evaluation of effectiveness and safety of leflunomide treatment in patients with active rheumatoid arthritis in whom methotrexate was ineffective or contraindicated. MATERIAL AND METHODS: Eighty one patients (66 women and 15 men) with RA diagnosed according to ARA (The American Rheumatism Association) criteria were included in the study. The mean age was 57.6+/-11.7 years and the mean disease duration was 7.7+/-7.1 years. The inclusion criteria were: disease activity according to DAS28 (Disease Activity Score)>3.2 and contraindications to methotrexate or ineffective methotrexate treatment for at least 3 months. At the beginning of the study 49 of patients were treated with methotrexate in weekly dose of 17+4.2mg and 32 were not treated with DMARDs. Oral glicocorticosteroids in stable doses of 5-15mg of prednisone were given to 66 (77.7%) of them. There was no statistically significant difference in radiological progression of the disease according to Steinbrocker's scale between groups (treated and not treated with methotrexate). Monotherapy with leflunomide was started with loading dose of 100mg for 3 days, and then 20mg daily. Combination therapy was introduced without loading dose. Evaluation was performed monthly and included: duration of morning stiffness, pain and disease activity according to VAS (visual-analogue) scale, the number of tender and swollen joints, blood count, ESR, CRP, aminotransferases activity, and the presence and intensity of adverse reactions. The results of treatment were evaluated after 5 months in 37 of patients and adverse reactions which happened until the end of 5th month were evaluated in all included patients. RESULTS: The mean DAS28 values improved exponentially during consecutive months and the difference between them was statistically significant. Adverse reactions during 5 months of treatment were observed in 36(44,4%) of patients and in 6(7,4%) of cases the treatment had to be stopped because of side effects. The frequency of adverse reactions was similar in monotherapy and combination therapy group. CONCLUSIONS: Leflunomide therapy can be effective in patients with active rheumatoid arthritis in whom methotrexate is contraindicated or insufficient. Combination of leflunomide with methotrexate is safe and does not increase the frequency of adverse reactions.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Isoxazoles/therapeutic use , Aged , Drug Therapy, Combination , Female , Humans , Leflunomide , Male , Methotrexate/therapeutic use , Middle Aged , Prednisone/therapeutic use , Treatment Outcome
6.
Pol Merkur Lekarski ; 20(118): 404-7, 2006 Apr.
Article in Polish | MEDLINE | ID: mdl-16886561

ABSTRACT

UNLABELLED: Wide range of different autoantibodies (e.g. rheumatoid factor, antinuclear antibodies, smooth muscle antibodies, anticardiolipin antibodies) can be detected in low titres in more than 70% of patients with chronic hepatitis. THE AIM OF THE STUDY: Prevalence of serological markers typical for rheumatic diseases in patients with chronic viral hepatitis was examined and the correlation between those markers and serum activity of liver enzymes was evaluated. MATERIAL AND METHODS: 80 patients (30 female and 50 male aged 43.5 +/- 10 years) with chronic viral hepatitis hospitalized in Department of Internal Diseases and Rheumatology of Medical Military Institute in Warsaw were included in the study. 16 of patients were infected with hepatitis virus B, 60 with hepatitis virus C, 4 suffered from both infections. Blood morphology, ESR, CRP aminotransferases activity, protein and bilirubin levels were measured in every patient. Serological examination included levels of antinuclear antibodies (ANA), smooth muscle antibodies (SMA), LKM-1, antineutrophil antibodies (ANCA), anticardiolipin antibodies (aCL), antimitochondrial antibodies (AMA), circulating immunological complexes (CIC), cryoglobulins and rheumatoid factor. RESULTS: At least one serological marker was found in 60 (75%) patients. Latex fixation reaction was positive in 42 (54%), rheumatoid factor was present in 25 (31%), aCL in 28 (34%), pANCA in 22 (27%) and CIC in 16 (20%). Antibodies ANA, AMA, LKM-1 and cryoglobulins were less frequently observed (6%, 5.5% and 7% respectively). The presence of autoantibodies was more frequent in patients with hepatitis C (77% vs. 62%). AMA, LKM-1 and cryoglobulins were detected only in that group of patients. There was no correlation between liver enzymes activity and presence of serological markers of rheumatic diseases. CONCLUSIONS: Serological markers considered to be typical for rheumatic disorders were detected in 75% patients (especially in patients with HCV). There is no correlation between aminotransferases activity and tested serological.


Subject(s)
Arthritis/diagnosis , Arthritis/epidemiology , Hepatitis, Viral, Human/epidemiology , Adult , Arthritis/blood , Autoantibodies/blood , Biomarkers/blood , Chronic Disease , Comorbidity , Female , Humans , Male , Serologic Tests
7.
Pol Merkur Lekarski ; 19(113): 642-5, 2005 Nov.
Article in Polish | MEDLINE | ID: mdl-16498802

ABSTRACT

UNLABELLED: Peptic ulcer is a common complication of upper gastrointestinal (uGI) bleeding, which refers to 20% of patients with duodenal and gastric ulcer. Non-steroidal anti-inflammatory drugs (NSAIDs) use is a well-known risk factor for ulcer formation and uGI bleeding. AIM OF THE STUDY: The evaluation of location and the cause od uGI bleeding and its association with NSDAIDs use. MATERIAL AND METHODS: We conducted a retrospective analysis of all patients hospitalized in our department from 2000 to 2001. RESULTS: Upper gastrointestinal bleeding was an indication for 3% of hospitalizations in our department. The cause of the bleeding was as follows: NSAIDs use side effect in 21 (42%) patients, portal hypertension in 6 (12%), acenocumarol overdosage in 2 (4%), not specified in 17 (34%). 13 (62%) of 21 NSAIDs-users chronically ingested small doses of acetylsalicylic acid. The most common sources of bleeding were: duodenal ulcer in 20 (40%), gastric or esophageal ulcer in 10 (20%), erosive gastroduodenitis in 8 (16%), esophageal varices in 6 (12%), not specified in 2 (4%) and not specified after acenocumarol overdosage in 2 (4%). One patient had coexisting gastric and duodenal ulcers, and one patient had coexisting erosive gastritis and duodenal ulcer In NSAIDs-users group, there were 9 (43%) patients with erosive gastroduodenitis, 8 (38%) with duodenal ulcer and 4 (19%) with gastric ulcer. CONCLUSION: On the basis of our observations we concluded that NSAIDs use (especially cardiological doses of acetylsalicylic acid) is a common cause of upper gastrointestinal bleeding. The most common source of bleeding in this group was erosive gastroduodenitis. The age over 65 years was an additional risk factor for uGI bleeding.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Peptic Ulcer Hemorrhage/chemically induced , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Peptic Ulcer Hemorrhage/epidemiology , Retrospective Studies
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