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171.
The type of test ingredients used for obtaining self-compacting high-performance concrete (HPSCC) has been carefully selected to be universal. For this purpose, an extensive statistical analysis of the obtained results of the literature research was carried out. Then, universal and adapted to the typical range, highly fit statistical models are presented that can support the HPSCC design process for achieving high strength. For this purpose, a broad plan of statistical research was used, namely multivariate selection of sidereal points, which allowed the use of as many as five variable factors at three levels of variability. The sidereal points were equal to the respective minimum and maximum input values. Additionally, based on the analysis of variance (ANOVA) for factorial systems with the interaction of the obtained test results, the significance of the impact of the tested material factors on the compressive strength of the HPSCC tested was determined.  相似文献   
172.
In this study, the results obtained by 19 laboratories participating in 2 editions of the interlaboratory comparison (ILC) determining 2 properties of ceramic tiles adhesives (CTAs), i.e., initial tensile adhesion strength and tensile adhesion strength after water immersion following EN 12004, were analyzed. The results show that participating laboratories maintain a constant quality of their work. The use of z-score analysis, under ISO 13528, allows for classifying 89.5% to 100% of laboratories as satisfactory, depending on the measurement’s kind and edition. The remaining laboratories are classified as questionable. The investigation of the predominant mode of failure of the CTA’s samples tested in the two editions shows significant differences. From the perspective of laboratories, the goal of the ILC has been achieved. From the standpoint of a manufacturer who evaluates a product’s properties when placing it on the market, the results indicate the necessity of a particular treatment of the product evaluation process because the variability of the obtained results is significant. It increases the possibility of the product failing to meet the assessment criteria verified by the construction market supervision authorities. The manufacturer must consider all possible variations in the risk analysis, including the ILC results, to improve the assessment process of CTAs.  相似文献   
173.
A six-step synthesis of xanthohumol (1a) and its d3-derivative (1b) from easily accessible naringenin is reported. The prenyl side chain was introduced by Mitsunobu reaction followed by the europium-catalyzed Claisen rearrangement and base-mediated opening of chromanone gave access to an α,β-conjugated ketone system. Compound 1b was used as an internal standard in stable isotope dilution assays of 1a in two Polish beers.

A six-step synthesis of xanthohumol and its d3-derivative from easily accessible naringenin is reported.

Xanthohumol (1a, Scheme 1A) is a naturally occurring prenylated chalcone produced by lupulin glands in female inflorescences of hop plants.1 In recent years, 1a has attracted significant attention due to its vast range of biological activities including cancer-preventive, antioxidative, anti-inflammatory, and antiviral.2–8 Such properties combined with low toxicity to the human body make 1a a prospective therapeutic agent, diet supplement, or ingredient of cosmetics.9 Although 1a was isolated from natural sources in 1913,10 the first synthesis of this compound was reported as late as in 2007.11 Several other syntheses have been reported since then, but only minor improvements have been achieved.12–14Open in a separate windowScheme 1The background of the study.Bioactive compounds labeled with stable isotopes (deuterium, carbon-13) are widely applied in metabolomic studies for tracking metabolic pathways and as internal standards in stable isotope dilution assays.15,16 Deuterated compounds are also considered as attractive drug candidates due to the influence of the kinetic isotope effect on pharmacokinetics.17–19 Although approaches to 13C-enriched xanthohumol20,21 and hydrogen/deuterium exchange in 1a22 were reported, no scalable and cost-effective synthesis of the deuterium-labeled derivative of 1a (i.e.1b) has been disclosed to date.Two main challenges have to be faced in the synthesis of 1a: (i) construction of a pentasubstituted aromatic ring containing a prenyl side chain and (ii) selection of suitable protecting groups for phenols. In the case of (i), phloroglucinol is used as a precursor and an acyl-substituent is introduced by Friedel–Crafts acylation with a subsequent Claisen–Schmidt condensation. The prenyl side-chain is introduced by Mitsunobu alkylation, followed by Claisen rearrangement. In the case of (ii), acid-sensitive alkoxymethyl protecting groups, removable under conditions in which 1a does not cyclize to isoxanthohumol (2a), are used most often (Scheme 1A).In this study, we have developed a synthetic approach for the formation of 1a and its deuterated analog 1b. We envisioned that both 1a and 1b can be directly obtained by the base-promoted chromanone ring-opening of 2a or 2b, which in turn can be obtained from easily accessible naringenin (3) (ca. 1 $/1 g) via two-step prenylation and Williamson etherification of the phenolic OH (Scheme 1B). The use of 3 as the starting material is beneficial as only one prenyl substituent has to be introduced.The synthetic route leading to 1a and 1b is depicted in Scheme 2. Our synthesis commenced from naringenin (3), which was selectively converted to diester 4 (Ac2O, pyridine). O-Alkylation of 4 under Mitsunobu conditions (3-methyl-2-butene-1-ol, Ph3P, DIAD), followed by the catalytic Claisen rearrangement of 5 (Eu(fod)3, 1,2-dichloroethane, 80 °C) afforded prenyl-derivative 6. Notably, performing the latter reaction in 1,2-dichloroethane above its boiling point was superior in comparison to earlier reports.23–26 Alkylation of 6 (CH3I, Ag2O or CD3I, Ag2O) afforded 7a/7b in good yields. An alternative approach to 7b involving the alkylation of phenolic OH under Mitsunobu conditions (CD3OD, Ph3P, DIAD) required a large excess of reagents and afforded the product in moderate yield. Basic hydrolysis (KOH, MeOH) of esters afforded isoxanthohumols 2a/2b. Although the chromane ring was stable during the hydrolysis, it could be opened under more harsh conditions (DBU, DMF, 70 °C),27,28 leading to 1a/1b in good yields after a mild acidic workup.Open in a separate windowScheme 2The synthetic route to 1a and 1b.With 1a and 1b in hand, we investigated their MS-fragmentation patterns in electrospray ionization in positive and negative ion modes. The MRM transitions were found by an automatic procedure and they are listed in for details). In positive ion mode, the most intensive product ions in fragmentation of 1a were ions with m/z values of 178.9, 299.0, 113.0, and 150.9. Corresponding ions with m/z +3 values can be found in the fragmentation of 1b. On the other hand, in the negative ion mode, the same product ions are observed both in the case of 1a and 1b, indicating that the CH3/CD3 groups were lost during fragmentations.The MRM transitions of 1a and 1b
Ionization mode1a1b
Precursor ionProduct ionPrecursor ionProduct ion
ESI(+)355.0178.9358.0182.0
299.0302.0
113.0115.9
150.9107.9
93.0154.0
ESI(−)353.0119.1356.0119.1
233.0236.0
295.1295.2
218.2175.0
175.0218.1
189.2168.2
Open in a separate windowOne of the criteria for an effective internal standard is the coelution of the labeled and non-labeled compounds during the HPLC analysis. This is particularly important in case of deuterium-labeled compounds as with the increase in the number of deuterons in the molecule, retention times may be extended. The retention times of 1a and 1b under different HPLC conditions are listed in
EntryConditionsRetention time [min]
1a1b
1Column: XB-C18, 100 × 3.0 mm, 2.6 μm, 100 Å; flow: 0.55 mL min−1; oven: 35 °C; gradient MeOH/0.1% HCO2H(aq): from 5% MeOH to 95% MeOH20.03020.034
2Column: Ace 5 C18-PFP, 250 × 4.6 mm; flow: 1.0 mL min−1, oven: 35 °C; isocrat. MeOH/0.1% HCO2H(aq): 80 : 2019.61519.700
3Column: polar-C18, 100 × 3.0 mm, 2.6 μm, 100 Å; flow: 0.55 mL min−1; oven: 35 °C; isocrat.: MeOH/0.1% HCO2H(aq): 65 : 356.5906.520
Open in a separate windowAs an example of applications, compound 1b was used as an internal standard in a stable isotope dilution assay of xanthohumol (1a) in two Polish beers (determined concentrations: 0.4069 mg L−1 and 0.5488 mg L−1, respectively). The developed MRM method allowed for the direct analysis of 1a and any preconcentration of the analyte was not needed.In conclusion, we have developed a six-step synthesis of xanthohumol (1a) and its deuterated analog 1b from naringenin (3) in total 19.8% yield for 1a and 23.3% for 1b. In a key step, isoxanthohumols 2a/2b were converted to the target compounds under basic conditions. The overall synthetic route was scalable and was used in the synthesis of 1a on a 5 g scale. The MRM transitions of 1b and its coelution with 1a makes 1b a suitable internal standard for the stable isotope dilution assay.  相似文献   
174.
IL-17A,IL-17E and IL-17F as Potential Biomarkers for the Intensity of Low-Grade Inflammation and the Risk of Cardiovascular Diseases in Obese People     
Ewelina Polak-Szczyby&#x;o  Jacek Tabarkiewicz 《Nutrients》2022,14(3)
Low-grade inflammation is a factor that predisposes to many obesity-related comorbidities. The immune mechanisms controlling the inflammatory response related to the secretory activity of adipocytes and its consequences for the organism are still under investigation. Methods: 84 obese adult volunteers (BMI ≥ 30 kg/m2) were tested by BIA. Serum samples were collected to analyze the concentrations of interleukins IL-17A, IL-17E and IL-17F. The subjects completed the original questionnaire, the FFQ-6 food consumption frequency questionnaire and the food diary. Results: The level of IL-17E and IL-17F was positively correlated with the BMI value and the level of IL-17E increased with the content of subcutaneous fat. Its increased blood concentration was also observed in individuals who declared that they were diagnosed with atherosclerosis and/or were taking beta-blockers. Products that were related with a low level of the above-mentioned interleukins were vegetables, groats, eggs, red meat, fast-food and alcohol. The level of these interleukins was positively correlated with the frequent consumption of confectionery and breakfast cereals. Nutrients that decreased the concentrations of IL-17 isoforms were potassium, iron, vitamins B6 and C, and folic acid. Conclusions: Both IL-17E and IL-17F may be closely related to the intensity of low-grade inflammation and be biomarkers of cardiovascular disease risk. Food products or the nutrients they contain may affect the levels of the above-mentioned interleukins as well as IL-17A.  相似文献   
175.
Basal cell carcinoma—Primary closure of moderate defect of mid forehead     
Iwona Chlebicka  Alicja Ryga&#x;  Aleksandra A. Stefaniak  Jacek C. Szepietowski 《Dermatologic therapy》2020,33(3)
This is a case presentation of successful defect repair after radical surgical excision of a moderately large basal cell carcinoma by a simple procedure taking advantage of a patient's individual face features.  相似文献   
176.
Surgical approach to the management of field cancerization: Own experience     
Karolina Wjcicka  Jacek C. Szepietowski 《Dermatologic therapy》2020,33(4)
The term field cancerization was proposed by Slaughter in 1953 to describe multifocal neoplastic lesions in the oral mucosa. Currently, it is well known that field cancerization can occur also in the skin. There is no one, universal and generally accepted management for the patients with multiple actinic keratosis and field cancerization. We presented two cases with large field cancerization on the face and the scalp. In both patients, we performed one stage surgery with split thickness skin graft with good final esthetic and functional result. Available literature on the role of classical surgical removal in treating field cancerization is very limited. We believe that surgery can be consider as an option for the treatment in some high risk patients with very large field cancerization, but further observation and evaluation of this method is needed.  相似文献   
177.
Role of Beta-Carotene in Lung Cancer Primary Chemoprevention: A Systematic Review with Meta-Analysis and Meta-Regression     
Jacek Kordiak  Filip Bielec  S&#x;awomir Jab&#x;o&#x;ski  Dorota Pastuszak-Lewandoska 《Nutrients》2022,14(7)
Lung cancer is one of the most common neoplasms globally, with about 2.2 million new cases and 1.8 million deaths annually. Although the most important factor in reducing lung cancer risk is lifestyle change, most patients favour the use of supplements, for example, rather than quitting smoking or following a healthy diet. To better understand the efficacy of such interventions, a systematic review was performed of data from randomized controlled trials concerning the influence of beta-carotene supplementation on lung cancer risk in subjects with no lung cancer before the intervention. The search corpus comprised a number of databases and eight studies involving 167,141 participants, published by November 2021. The findings indicate that beta-carotene supplementation was associated with an increased risk of lung cancer (RR = 1.16, 95% CI = 1.06–1.26). This effect was even more noticeable among smokers and asbestos workers (RR = 1.21, 95% CI = 1.08–1.35) and non-medics (RR = 1.18, 95% CI = 1.07–1.29). A meta-regression found no relationship between the beta-carotene supplementation dose and the size of the negative effect associated with lung cancer risk. Our findings indicate that beta-carotene supplementation has no effect on lung cancer risk. Moreover, when used as the primary chemoprevention, beta-carotene may, in fact, increase the risk of lung cancer.  相似文献   
178.
Comparative Study of Effects of Air-Entraining Plasticizing Admixture and Lime on Physical and Mechanical Properties of Masonry Mortars and Plasters     
Ma&#x;gorzata Go&#x;aszewska  Jacek Go&#x;aszewski  Jerzy Bochen  Grzegorz Cygan 《Materials》2022,15(7)
This article presents research on selected physical and mechanical properties of cement-based plasters and masonry mortars with consistency-improving additives, namely, traditional hydrated lime and a plasticizing and aerating mixture (APA), which, in practice, is often considered to be a lime substitute. Comparative analysis of the properties of mortars with alternative additives—lime or APA—was carried out, taking into consideration possible effects of cement, as two types of Portland cement were used for the research. For fresh mortar, mixture consistency, air content, resistance to segregation, and water retention were determined. Tests on hardened mortars included tests of porosity and impermeability, depth of penetration of water under pressure, drying shrinkage, as well as compressive and bending strength, modulus of elasticity, and adhesion of mortars to the base. In addition, research has shown that cement–lime mortars and cement mortars with APA admixture of similar consistency in the fresh state are characterized by significantly different properties. The results show, in most of the features analyzed, more favorable properties of mortars with the use of traditional lime. For shrinkage only, the use of admixture turned out to be more advantageous.  相似文献   
179.
Morphine decreases ticagrelor concentrations but not its antiplatelet effects: a randomized trial in healthy volunteers          下载免费PDF全文
Eva‐Luise Hobl  Birgit Reiter  Christian Schoergenhofer  Michael Schwameis  Ulla Derhaschnig  Jacek Kubica  Thomas Stimpfl  Bernd Jilma 《European journal of clinical investigation》2016,46(1):7-14
  相似文献   
180.
Glucosamine sulfate and cartilage type II collagen degradation in patients with knee osteoarthritis: randomized discontinuation trial results employing biomarkers     
Cibere J  Thorne A  Kopec JA  Singer J  Canvin J  Robinson DB  Pope J  Hong P  Grant E  Lobanok T  Ionescu M  Poole AR  Esdaile JM 《The Journal of rheumatology》2005,32(5):896-902
OBJECTIVE: To determine whether glucosamine sulfate has an effect on cartilage type II collagen degradation in patients with knee osteoarthritis (OA). METHODS: A randomized, double blind, placebo controlled glucosamine discontinuation trial was conducted in 137 subjects with knee OA, who had had at least moderate relief of knee pain after starting glucosamine. Subjects were randomized to glucosamine at prestudy dose or placebo at an equivalent dose. Treatment was continued to Week 24 or disease flare, whichever occurred first. Serum and urine samples were collected at Weeks 0, 4, 12, and 24 or flare visit. Samples were analyzed in triplicate for 2 type II collagen degradation biomarkers: C2C epitope (COL2-3/4C(long)) and C1,2C epitope (COL2-3/4C(short)). The primary outcome was the mean change in serum and urine C1,2C/C2C ratio in the glucosamine and placebo groups from baseline to final (flare or Week 24) visit. Linear regression analyses were conducted to adjust for potential confounders. Due to non-normal distributions, the data were log-transformed (lnC1,2C/C2C). Secondary outcomes included comparison of mean change scores at final visit compared to baseline for serum and urine C1,2C and C2C in the 2 treatment groups and in Flare versus No-Flare groups. RESULTS: Baseline and final visit samples were available in 130 subjects for serum analysis and 126 subjects for urinalysis. No significant difference was seen between placebo and glucosamine groups in the serum C1,2C/C2C ratio, with a mean (SD) change from baseline to final visit of 0.8 (27.8) and -0.1 (1.8), respectively (mean difference 0.9; 95% CI -6.0, 7.7, p = 0.80). Similarly, no differences between treatment groups were seen for mean change in urine C1,2C/C2C (p = 0.82), or for mean change in C2C or C1,2C. In linear regression analysis, after adjustment for sex, radiographic severity, baseline lnC1,2C/C2C ratio, WOMAC function, and flare status, treatment was not a significant predictor of final serum or urine lnC1,2C/C2C ratio. When those who experienced flare were contrasted with those without flare, there was a nonsignificant trend toward a difference in mean baseline to final visit change score for serum C1,2C/C2C ratio (p = 0.12). In addition, in the multivariable linear regression analysis, flare status showed a borderline association with final visit serum lnC1,2C/C2C ratio (p = 0.16). CONCLUSION: No statistically significant effect of glucosamine sulfate on type II collagen fragment levels in serum or urine was observed for knee OA over 6 months. Further research is necessary to elucidate which biopathologic systems, if any, are affected by glucosamine treatment. While collagen degradation products may be of value in predicting progression, at least as defined by clinical flare, a larger dataset would be needed to prove this.  相似文献   
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