Die Veränderung des Isoelektrischen Punktes des Hämoglobins und Seine Beziehungen zum Säure-Basenhaushalt

Ohne Zusammenfassung     

Effect of Laser Heating on the Life of Cutting Tools Coated with Single- and Multilayer Coatings Containing a TiN Layer

This study proposes a novel use of laser heating to increase the adhesion between coatings fabricated by low-temperature PVD and replaceable cemented carbide cutting inserts, thus extending the life of these cutting tools in the machining of difficult-to-machine materials. Our previous studies conducted on CVD coatings showed that these coatings had higher adhesion due to a much higher process temperature. However, taking into account the fact that PVD coatings have better technological properties (e.g., lower structure porosity, higher hardness, and better tribological properties) than CVD coatings, it is fully justified to investigate ways of improving the PVD coating adhesion to the substrate. In this study, replaceable cutting inserts with different hard coatings of titanium nitride were used. Laser heating was conducted with different power densities. The adhesion strength of the tested coatings was determined via vibration spectrum analysis. In addition, 2D surface imaging, scanning electron microscopy, and X-ray fluorescence spectrometry were employed to examine the coatings after laser heating. A significant increase in the adhesion of single-layer (TiN) and double-layer (TiCN + TiN) coatings to the cemented carbide substrate, together with increased tool life, was observed after heating the samples with 40% of the maximum laser power. The application of a multilayer coating containing thermal shock-sensitive (TiAlSi) N did not increase the tool life. This paper attempts to interpret the obtained results.     

An Evaluation of the Hydrolytic Stability of Selected Experimental Dental Matrices and Composites

Materials with potential use as dental restoration should be evaluated in an aggressive environment. Such accelerated aging is widely used in other industries and allows the assessment of service life. In the presented study, three neat resins (UDMA/Bis-GMA/TEGDMA 70/10/20 wt.%, UDMA/Bis-GMA/TEGDMA 40/40/20 wt.% and UDMA/Bis-EMA/TEGDMA 40/40/20 wt.%) and three composites based on these matrices were tested before and after aging protocols (I-7500 cycles, 5 °C and 55 °C, water and 7 days, 60 °C, 0.1 M NaOH; II-5 days, 55 °C, water and 7 days, 60 °C, 0.1 M NaOH). Flexural strength (FS), diametral tensile strength (DTS) and hardness (HV) were determined. Applied aging protocols resulted in a decrease in the value of the FS, DTS and HV. Larger changes were noticed for the neat resins. Materials in which the content of bis-GMA was lower or substituted by bis-EMA showed better resistance to degradation. The choice of mixtures with monomers characterized by lower sorption values may favorably affect hydrolytic stability. It was shown that for composites there was a drastic decrease in hardness, which suggests a more superficial effect of the used protocols. However, degradation of the surface layer can result in a growing problem over time given that the mastication processes are an inherent element in the oral environment.     

Vasospastic Angina with J‐Wave Pattern and Polymorphic Ventricular Tachycardia Effectively Treated with Quinidine

Background: Myocardial ischemia during coronary spasm may generate malignant ventricular arrhythmias. The J‐wave pattern was suggested to be a marker of a disorder associated with life‐threatening arrhythmias. Results: We report the case of a patient with vasospastic angina and J‐wave pattern in inferior and lateral leads associated with polymorphic ventricular tachycardia which was effectively treated only with quinidine—vasodilating drugs were not able to prevent the arrhythmia although they were effective in preventing ischemic events. Conclusion: The J‐wave pattern in inferolateral leads may be a sign of electrical vulnerability to lethal ventricular arrhythmia in patients suffering from vasospastic angina—quinidine can effectively prevent such arrhythmias in these patients.     

Avian Feathers as Bioindicators of the Exposure to Heavy Metal Contamination of Food

The aim of this study was to determine the possibility of using feathers of blue tit nestlings to assess the level of endogenous accumulation of lead. For this purpose we conducted an experiment with lead application to randomly chosen nestlings from eight randomly drawn broods. Five days after the exposure, feathers of lead-treated nestlings had significantly higher lead concentrations than control nestlings. This result suggests that feathers can be used as reliable non-destructive bioindicators to assess the level of heavy metals originating from contaminated food, which is of great significance for comparative studies on ecological consequences of pollution.     

BCL11B,FLT3, NOTCH1 and FBXW7 mutation status in T-cell acute lymphoblastic leukemia patients

T‐cell acute lymphoblastic leukemia is a heterogeneous malignancy originating from developing lymphocyte precursors likely due to mutations in genes regulating thymocyte differentiation. Here, we characterized mutation status of BCL11B and FLT3 genes, presumably involved in T-ALL, together with FBXW7 and NOTCH1 as known players in T-ALL in 65 pediatric T-cell acute lymphoblastic leukemia patients. We also aimed at the assessment of prognostic value of NOTCH1 and FBXW7 mutations in ALL-IC BFM 2002 protocol.FLT3 and BCL11B mutations were detected in 3% and 2% of patients, respectively. FBXW7 mutations were observed in 8% of patients, while NOTCH1 was mutated in 40%. No correlation was found between NOTCH1 and FBXW7 mutations and traditionally used clinical factors or molecular features. In total we have detected nine mutations, which have not been previously described by others. Eight of them were found in NOTCH1 and one in BCL11B gene.Observed frequencies of NOTCH1 and FBXW7 are in line with previous reports, thus confirming postulated participation of these two genes in T-ALL pathomechanism. Moreover, we report on mutation frequency of FLT3 and BCL11B, not extensively studied in T-ALL so far. Finally, we suggest a putative role of BLC11B as an oncogene in T-ALL pathogenesis.     

The use of polypropylene mesh in midline incision closure following gastric by-pass surgery reduces the risk of postoperative hernia

BACKGROUND: Incisional hernia is a common problem following Roux-en-Y gastric bypass for morbid obesity. PATIENTS AND MATERIALS: We report the preliminary results of nonrandomized prophylactic use of polypropylene mesh in a group of 60 consecutive patients. The patients with highest body mass index, and/or history of abdominal hernias and profound liver damage had abdominal wall reinforced with mesh during an operation. A year later the wound was assessed in all patients. RESULTS: In standard wound closure group (n=48) incisional hernia was found in 9 cases (20%). None of the patients with inserted mesh (n=12) developed hernia. The length of hospital stay in mesh group was similar to that in the nonmesh group and shorter than in patients with hernia occurrence. Mesh insertion was complicated with wound discharge in three patients. CONCLUSIONS: In our opinion prophylactic use of polypropylene mesh in bariatric patients is highly effective in postoperative hernia prevention.     

Normative data on the Bonn Risk Index for calcium oxalate crystallization in healthy children

Bonn Risk Index (BRI) is being used for the assessment of urinary calcium oxalate (CaOx) crystallization. There are no published data regarding BRI during growth. The objective of this study was to establish age- and sex-dependent BRI values in healthy children and adolescents. A total of 1,050 Caucasian subjects aged 3–18 years (525 males, 525 females) without a history of kidney stone disease were enrolled in the cross-sectional study. The study group was divided into 15 ranges according to age, each comprising 70 subjects. Urinary ionized calcium [Ca²⁺] was measured using a selective electrode while the onset of spontaneous crystallization was determined using a photometer and titrating with 40 mmol/L ammonium oxalate (Ox²⁻). The calculation of BRI value was based on the ratio of [Ca²⁺] to the required amount of ammonium oxalate added to 200 ml of urine to induce crystallization. The median BRI was 0.26 1/L and the values of the 5th and 95th percentiles were 0.06 1/L and 1.93 1/L, respectively. BRI correlated positively with body-area-related BRI (1/L × 1.73 m²) (R = 0.18; P < 0.05), whereas a negative correlation was found between BRI and body weight (1/L × kg) (R = −0.85; P < 0.05). Neither sex nor age differences were detected in BRI across studied children and adolescents. The values of Bonn Risk Index were constant during growth and there was a limited influence of age and sex on BRI in children over 3 years of age. The BRI may be valuable in the evaluation of pediatric patients at risk for kidney stones, particularly if the BRI from stone formers is demonstrated to be higher than in normal children.