The Influence of Potassium Hexafluorophosphate on the Morphology and Anticorrosive Properties of Conversion Coatings Formed on the AM50 Magnesium Alloy by Plasma Electrolytic Oxidation.

In this study, conversion coatings were produced on the AM50 magnesium alloy by a plasma electrolytic oxidation (PEO) process in alkaline-silicate electrolyte with the addition of potassium hexafluorophosphate, using a unipolar pulse power source. The coating microstructure and its composition were determined using scanning electron microscopy (SEM) and an X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the conversion coatings was evaluated by means of potentiodynamic polarization tests (PDP) and electrochemical impedance spectroscopy (EIS) in a dilute Harrison solution (DHS). It has been found that the properties (microstructure, composition, and coating thickness) of the obtained layer and, therefore, their anticorrosive resistance strongly depend on the electrolyte composition. The best anticorrosive properties were observed in the layers obtained in the presence of 2.5 g/L KPF6. It was found that the conversion coating produced with the addition of hexafluorophosphate is characterized by a different morphology (sponge-like) and better anticorrosion properties, in comparison to the coating obtained with the addition of fluoride and orthophosphate salts commonly used in PEO synthesis. The sponge-like structure, which is similar to bone structure in combination with the presence of phosphates in the layer, can increase the biocompatibility and the possibility of self-healing of this coating. However, neither Mg(PF6)2, nor any other compounds containing PF6-, have been found in the layers produced.

Characteristics of Impulse Carburization LPC Process.

In the present work, Pyrowear53 steel was subjected to the impulse carburizing LPC process. After carburation, the material was quenched and tempered. Postprocessing analyses included the measurement of hardness, carbon content, residual austenite, and residual stresses. The results revealed that the thermochemical treatment resulted in the formation of an approximately 1200 µm wide carburized layer. The results of hardness, carbon content, and residual austenite measurement showed a continuous gradient (drop) in the measured values within the carburized layer. However, the results of residual stresses revealed the existence of a local extremum, namely, a zone with higher compressive stresses at the depth between 600 and 1000 µm. This was explained by a different temperature for initiation of martensite transformation as a function of carbon content. This difference resulted in the occurrence of two martensite expansion fronts at two different depths, resulting in an increase in compressive stresses at the noted depth range. Moreover, it was concluded that this region was present for material containing between 0.8 and 0.4 wt% carbon for Pyrowear53.

Oxidation Behavior of Inconel 740H Nickel Superalloy in Steam Atmosphere at 750 °C.

The oxidation behavior of the nickel superalloy Inconel 740H was studied at 750 °C for 100, 250, 500, 1000, and 2000 h in a steam atmosphere. Microstructure observations were performed using scanning electron microscopes and scanning-transmission electron microscope. The phase identification of existing oxidation products was conducted by electron diffraction in transmission electron microscope. The obtained results showed that the microstructure of Inconel 740H was stable during the oxidation process. The kinetic data showed that the superalloy has the ability to form protective oxide layers that are characterized by good adhesion and no tendency to spallation during the test. The oxidation products were mainly composed of external and internal oxides mainly at grain boundaries. The oxides in the external layer were Cr2O3, MnTiO3,, and α-Al2O3 after 2000 h of oxidation. Internal oxides were α-Al2O3 and TiO2. The occurrence of discontinuities in the internal oxidation zone was also observed after 500 h of test. It was found that the thickness of the internal oxidation zone was greater than the thickness of the external oxide layer, which proves the strong tendency of the superalloy to form internal oxides after oxidation in the steam atmosphere.

Consequences of Different Mechanical Surface Preparation of Ni-Base Alloys during High Temperature Oxidation.

The influence of surface roughness on its high temperature oxidation for an Ni-base superalloy was studied using laser profilometry, atomic force microscopy, mass change measurements, glow-discharge optical emission spectrometry, scanning electron microscopy, X-ray diffraction, and positron annihilation methods. The isothermal and cyclic air oxidation tests were performed at 1000 °C and showed dependence of oxidation behavior on surface roughness. Smoother surfaces oxidation resulted in the formation of a multilayered oxide scale consisting of NiO, Cr2O3, and internally oxidized Al2O3 while a rougher surface formed protective Al2O3 scale. The factors responsible for different oxidation behaviors were determined as higher concentration of vacancies and increased residual stresses in the near-surface region of studied alloys.

Pentavalent Vanadium Species as Potential Corrosion Inhibitors of Al2Cu Intermetallic Phase in the Sulfuric(VI) Acid Solutions.

The objective of this work was to test vanadium isopolyoxoanions as potential corrosion inhibitors of the intermetallic phase Al2Cu in sulfuric acid solutions at pH = 1.3 and 2.5. The intermetallic was melted in an electric arc furnace. Its phase composition was confirmed using X-ray diffraction, light microscopy, and differential scanning calorimetry. Then Al2Cu corrosion kinetics was studied. Chemical composition of the solution after corrosion was determined using inductively coupled plasma-optical emission spectroscopy. The surface of corroded specimens was analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy. Subsequent electrochemical studies involved determination of open-circuit potential, electrochemical impedance spectra, and polarization curves. It was found that the Al2Cu phase corrodes selectively and vanadium isopolyoxoanions increase this process both at pH = 1.3 and 2.5 with two exceptions. Corrosion inhibition was observed for 100 and 200 mM of Na3VO4 at pH 1.3, with inhibition efficiency 78% and 62% respectively, due to precipitation of V2O5.

The Effect of Withdrawal Rate on Crystal Structure Perfection, Microstructure and Creep Resistance of Single Crystal Castings Made of CMSX-4 Nickel-Based Superalloy.

This study focuses on the evaluation of the crystal structure perfection in the single crystal made of CMSX-4 nickel superalloy and its effect on creep resistance. Single crystal castings were manufactured by directional solidification process at the withdrawal rate of 1, 3, 5 and 7 mm/min. Light (LM) and electron (SEM, TEM) microscopy, X-ray diffraction and Mossbauer spectroscopy were used for evaluation of the microstructure and crystal structure perfection. Castings were also subjected to creep tests. The best creep resistance was obtained for the casting manufactured at the withdrawal rate of 3 mm/min, characterized by the highest crystal structure perfection compared to the other castings examined.

Plasma Free Fatty Acids and their Binding Proteins in Preterm Infants.

BACKGROUND/AIMS: The objective of the study was to evaluate the circulating concentrations of plasma free fatty acids (FFA), fatty acid binding proteins: FABP-1 and FABP-4 in preterm infants depending on different feeding protocol. METHODS: A total of 43 premature infants (≤34 weeks) were enrolled in the study, and divided into 3 subgroups: nursed while staying in the department (53%), breast-fed only during the first 24 h (16%), and formulafed from the beginning (31%). The control group consisted of 12 healthy, full-term, breast-fed newborns. Blood samples were collected after delivery and 1 month later. We measured plasma concentrations of FFA, FABP-1, and FABP-4. RESULTS: FFA plasma concentrations were significantly lower in preterm babies when compared to control group (p = 0.003) in the prenatal period. After 1 month, a significant decrease in FFA concentration was noted in all groups of preterm babies independently from feeding protocol. After a month, breast-fed preterm infants and controls had significantly lower FABP-1 levels than preterm formula-fed infants (all p < 0.05), while the highest concentrations of FABP-4 were noted in formula-fed preterm infants when compared to breast-fed preterm infants and the control group (all p < 0.05). CONCLUSIONS: Prematurity is connected with disturbances in plasma FFA concentrations. FABP-1, as well as FABP-4, plasma levels in preterm infants depend on feeding protocol.

Impact of Fasting on Complete Blood Count Assayed in Capillary Blood Samples.

BACKGROUND: To determine the effect of food intake on complete blood count (CBC) results. METHOD: We analyzed the CBC in whole capillary blood specimens collected from 33 adult volunteers into microtubes between 8:00 AM and 11:00 AM. Blood specimens were drawn from patients who had been fasting 12 hours and then 1 and 2 hours after consumption of a light meal containing carbohydrates, protein, and lipids. All measurements were performed using the hematologic analyzer Sysmex XN-1000. RESULTS: The red blood cell count, hemoglobin concentration, hematocrit level, and platelet count decreased 2 hours after meal consumption (P = .007, P = .008, P = .003, and P = .03, respectively). The lymphocyte number decreased after the first and second hour following meal consumption (P = .004 and P = .001); the number of neutrophils had increased 1 and 2 hours after food intake (P = .003 and P = .006, respectively). CONCLUSIONS: Food consumption impacts CBC results. To ensure the consistency, quality, and repeatability of CBC analysis, blood should be drawn from fasting patients.

Benefits of ultrasound-guided transversus abdominis plane block for open appendectomy in children.

BACKGROUND: One of the most frequently performed emergency surgical procedures in children is an appendectomy. The aim of this study was to determine the benefits of supplementing standard, general anaesthesia with the ultrasound-guided right TAP block. METHODS: We analyzed the medical records of 90 children of both sexes, aged 4-16 years with a body mass of 16-78 kg who underwent general anaesthesia for open appendectomy. Sixty-two individuals were anaesthetized using the standard method, while 28 patients had an additional right-sided TAP block under ultrasound guidance. Subsequently these groups were divided into 2 subgroups: children under 8 years and those older. We evaluated the total consumption of opioids, intraoperative fentanyl requirement, the amount of non-opioid analgesic and antiemetic drugs used during the whole hospitalization, time to recovery of digestive track function and length of hospital stay. RESULTS: TAP block performed under USG guidance reduced the overall consumption of opioids (0.36 vs. 0.42 mg kg⁻¹, P = 0.048), significantly shortened time of fasting after the surgery (17 vs. 29 hours, P = 0.003) as well as reduced the need for antiemetic drugs: ondansetron were used only in 21.4% of children in the group with TAP block vs. 38.7% of children with standard protocol. Additionally, we noted that the application of the TAP block shortened the length of hospitalization (3 vs. 4 days, P = 0.045). CONCLUSION: The application of the TAP block, as a supplementary treatment to standard general anaesthesia for open appendectomy in children is a valuable component of multimodal analgesia, which might improve the quality of life of the patient and shorten the length of hospitalization.

[Determinants of the elevated factor VIII activity in patients following venous thromboembolism]. / Czynniki determinujace wysoka aktywnosc czynnika VIII u pacjentów po przebytej zylnej chorobie zakrzepowo-zatorowej.

INTRODUCTION: Activity of factor VIII (FVIII) increased above 150% of reference range predisposes to venous thromboembolism (VTE). The aim of this study was to identify predictors of increased FVIII activity in patients following VTE. MATERIALS AND METHODS: 241 (38% men) patients presented due to objectively documented VTE episode at least 3 months ago were included in this study. FVIII activity was measured using a clotting assay on the analyzer BCS XP. RESULTS: Among 241 patients with VTE, activity of FVIII above 150% (FVIII ≥ 150%) was observed in 96 (40%). These patients were older (p = 0.035) and their concentrations of fibrinogen and C-reactive protein (CRP) were higher by 12% and 88% (p < 0.001), respectively, compared with other patients. There was a positive correlation between FVIII and fibrinogen (r = 0.34; p < 0.001), FVIII and CRP (r = 0.30; p < 0.001). Type of treatment, time from the VTE episode and type of VTE were not associated with FVIII. Twenty patients (8%) had activity of FVIII increased above 200% (FVIII > 200%) and this group was also older (p = 0.015), more patients in that group had obesity (p = 0.015), idiopathic VTE (p = 0.043), less of them had positive family history (p = 0.010) and they were characterized by fibrinogen and CRP increased by 28% (p < 0.001) and 102% (p = 0.004), respectively, compared with patients with FVIII between 150-200%. Independent predictors of FVIII ≥ 150% were: fibrinogen (p < 0.001), bilirubin (p = 0.002), hemoglobin (p = 0.016), glucose (p = 0.040), CRP (p = 0.023), total homocysteine (p = 0.032). Fibrinogen was the only independent predictor of FVIII > 200% (p = 0.016). CONCLUSIONS: The activity of FVIII in patients after VTE episode is influenced by age, concentration of fibrinogen, bilirubin, hemoglobin, glucose, CRP and homocysteine. Our results suggest the role of environmental factors, mainly inflammatory response in maintaining elevated FVIII activity following VTE.

Children with alcohol intoxication in Cracow, Poland.

Alcoholism among minors is a serious social problem. The aim of the current study was to analyze alcohol intoxication in children based on hospitalizations in the University Children's Hospital in Cracow between the years 2007 and 2015. During these 9 years, 381 patients were hospitalized due to excessive alcohol consumption. Most patients were junior high school or high school students. The highest blood alcohol concentrations in hospitalized patients were found in a 16-year-old boy (BAC .41%) and a 15-year-old girl (BAC .37%). Alcohol consumption and severe intoxication are linked to a wide variety of familial, social, and personal problems.

Determinants of Elevated Levels of Natural Anticoagulants in Healthy Subjects.

BACKGROUND: The levels of protein C (PC), free protein S (PS) and antithrombin (AT) are evaluated during thrombophilia screening to exclude their deficiencies. OBJECTIVES: The aim of this study was to investigate factors which determine the elevated levels of natural plasma anticoagulants in healthy individuals. MATERIAL AND METHODS: The PC activity and antigen, free PS antigen and AT activity together with hematological, biochemical, genetic and immunological laboratory tests were assessed in 130 healthy adults (63 males) aged 20-60 (median 41) years. Individuals with personal or family history of cardiovascular diseases and venous thromboembolism were ineligible. RESULTS: The functionally active PC measured by chromogenic assay (values above 140%) was observed in 14 (11%) of subjects, while the PC antigen determined using the enzyme-linked immunosorbent assay (ELISA) was elevated in 5 (4%) of these patients. Free PS measured by immunoturbidimetry and ELISA was increased in 9 (7%) subjects (values above 139% in men and 114% for women) and in 6 (5%) patients (values above 130% in men and 111% for women), respectively. The AT activity above 118% was found in 5 (4%) subjects measured using chromogenic assay. None of the individuals had any deficiency of natural anticoagulants. Increased C-reactive protein (CRP)>3.0 mg/L was associated with elevated PC activity (odd ratio [OR]: 11.14, 95% confidence interval [CI] 1.67-74.23). Increased free PS assessed by immunoturbidimetric assay and PC activity were associated with hypercholesterolemia (OR: 3.57, 95% CI: 1.09-10.06 and OR: 8.61, 95% CI: 1.07-69.04, respectively). Body mass index≥25 kg/m2 was independently associated with elevated PC activity (OR: 3.42, 95% CI: 1.01-11.52). No risk factors for elevated AT activity were identified. CONCLUSIONS: Apart from hypercholesterolemia and overweight, increased serum CRP is associated with elevated PC activity in healthy adults. We confirmed that there are differences in the proportions of subjects with elevated PC and PS depending on the assay used.

Peptides from adipose tissue in mental disorders.

Adipose tissue is a dynamic endocrine organ that is essential to regulation of metabolism in humans. A new approach to mental disorders led to research on involvement of adipokines in the etiology of mental disorders and mood states and their impact on the health status of psychiatric patients, as well as the effects of treatment for mental health disorders on plasma levels of adipokines. There is evidence that disturbances in adipokine secretion are important in the pathogenesis, clinical presentation and outcome of mental disorders. Admittedly leptin and adiponectin are involved in pathophysiology of depression. A lot of disturbances in secretion and plasma levels of adipokines are observed in eating disorders with a significant impact on the symptoms and course of a disease. It is still a question whether observed dysregulation of adipokines secretion are primary or secondary. Moreover findings in this area are somewhat inconsistent, owing to differences in patient age, sex, socioeconomic status, smoking habits, level of physical activity, eating pathology, general health or medication. This was the rationale for our detailed investigation into the role of the endocrine functions of adipose tissue in mental disorders. It seems that we are continually at the beginning of understanding of the relation between adipose tissue and mental disorders.