Effect of Applied Pressure on the Electrical Resistance of Carbon Nanotube Fibers.

Carbon nanotubes (CNTs) can be spun into fibers as potential lightweight replacements for copper in electrical current transmission since lightweight CNT fibers weigh <1/6th that of an equivalently dimensioned copper wire. Experimentally, it has been shown that the electrical resistance of CNT fibers increases with longitudinal strain; however, although fibers may be under radial strain when they are compressed during crimping at contacts for use in electrical current transport, there has been no study of this relationship. Herein, we apply radial stress at the contact to a CNT fiber on both the nano- and macro-scale and measure the changes in fiber and contact resistance. We observed an increase in resistance with increasing pressure on the nanoscale as well as initially on the macro scale, which we attribute to the decreasing of axial CNT…CNT contacts. On the macro scale, the resistance then decreases with increased pressure, which we attribute to improved radial contact due to the closing of voids within the fiber bundle. X-ray photoelectron spectroscopy (XPS) and UV photoelectron spectroscopy (UPS) show that applied pressure on the fiber can damage the π-π bonding, which could also contribute to the increased resistance. As such, care must be taken when applying radial strain on CNT fibers in applications, including crimping for electrical contacts, lest they operate in an unfavorable regime with worse electrical performance.

A new approach to enhancing the CO2 capture performance of defective UiO-66 via post-synthetic defect exchange.

Zirconium-based metal-organic frameworks (Zr-MOFs) are a subclass of MOFs known for their remarkable stability, especially in the presence of water. This makes them extremely attractive for practical applications, including CO2 capture from industrial emission sources; however, the CO2 adsorption capacity of Zr-MOFs is moderate compared to that of the best performing MOFs reported to date. Functionalization of Zr-MOFs with amino groups has been demonstrated to increase their affinity for CO2. In this work, we assessed the potential of post-synthetic defect exchange (PSDE) as an alternative approach to introduce amino functionalities at missing-cluster defective sites in formic acid modulated UiO-66. Both pyridine-containing (picolinic acid and nicotinic acid) and aniline-containing (3-aminobenzoic acid and anthranilic acid) monocarboxylates were integrated within defective UiO-66 with this method. Non-defective UiO-66 modified with linkers bearing the same amino groups (2,5-pyridinedicarboxylic acid and 2-aminoterephthalic acid) were prepared by classical post-synthetic ligand exchange (PSE), in order to compare the effect of introducing functionalities at defective sites versus installing them on the backbone. PSDE reduces the porosity of defective UiO-66, but improves both the CO2 uptake and the CO2/N2 selectivity, whereas PSE has no effect on the porosity of non-defective UiO-66, improving the CO2 uptake but leaving selectivity unchanged. Modification of defective UiO-66 with benzoic acid reveals that pore size reduction is the main factor responsible for the observed uptake improvement, whereas the presence of nitrogen atoms in the pores seems to be beneficial for increasing selectivity.

[Acquired von Willebrand's disease in the course of severe primary hypothyroidism in a patient with autoimmune polyglandular syndrome type 3]. / Zespól nabytego niedoboru czynnika von Willebranda w przebiegu glebokiej pierwotnej niedoczynnosci tarczycy u chorej z autoimmunologicznym zespolem niedoczynnosci wielogruczolowej typu III.

The case of a 20-year old female, who had been followed because of von Willebrand disease (vWD) was presented in this paper . She had a past history of menorrhagia and bleeding after dental procedures and the activity of von Willebrand factor (vWF) was decreased. Because of suggestive clinical features, the workup for hypothyroidism was performed and the patient was found to have severe hypothyroidism due to Hashimoto thyroiditis. After the institution of replacement therapy with levothyroxine, von Willebrand factor activity returned to normal range and symptoms of von Willebrand disease disappeared. Based on these findings, the diagnosis of acquired von Willebrand syndrome (AvWS) due to hypothyroidism was made. The development of myasthenia led to the final diagnosis of autoimmune polyglandular syndrome type 3 (APS) with myasthenia gravis and vitiligo.

[Hemostatic disturbances in obesity]. / Zaburzenia hemostazy u osób otylych.

Overweight and obesity belong to the group of chronic diseases in which there is a substantially increased risk of thromboembolic incidents. The changes involve both arterial and venous system. The decisive role in their development seems to have disorders ofhemostasis including both excessive activation of coagulation system and/or inhibition of fibrinolysis. Coagulation changes in obese persons are complex. They include, among others, increase in concentration and activity of blood clotting factors, hyperfibrynogenemia and overeactivity ofplatelets. On the other hand, inhibition of normal fibrinolysis occurs in obese persons. The goal of this study was to examine disorders of coagulation and fibrinolysis developing in obese persons, taking also into account hormonal and metabolic changes, endothelium damage and the influence of adipocytokines on the hemostasis mechanisms.

[Thrombocytopenia and other extrahepatic manifeststions of hepatitis C virus infection--case report]. / Maloplytkowosc i inne pozawatrobowe zaburzenia w przebiegu zakazenia wirusem zapalenia watroby typu C--opis przypadku.

Authors present a case of forty seven years old woman with thrombocytopenia in the course of hepatitis C virus infection. Thrombocytopenia might be related to immunological mechanisms or be an effect of hypersplenism. Moreover mixed cryoglobulinemia, lymphocytic autoimmune thyroiditis with hypothyroidism and other laboratory abnormalities (impaired rate of lymphocytes CD4 to CD8, increase of B cells and natural killer cells, hypocomplementemia, hypergammaglobulinemia, increase of immune complexes concentration) were revealed. Above-mentioned abnormalities might be an effect of hepatitis C virus infection.

[Multi-reasons, severe megaloblastic anaemia--description of two cases]. / Wieloprzyczynowa ciezka niedokrwistosc megaloblastyczna--opis dwóch przypadków.

We report two cases of young patients (44 and 26 years old) with severe macrocytic, megaloblastic anaemia in course of Addison-Biermer's disease. In addition we found also other reasons of vitamin B12 deficiency. The one of them was chronic autoimmune thyroiditis and the second was, surely, Helicobacter pylori infection. The presented cases confirm the importance of spreading the diagnosis with antithyroid antibodies detection and Helicobacter pylori test in all patients with Addison-Biermer's diseaese.

[Hyperhomocysteinemia complicated by myocardial infarction and portal vein thrombosis--case report]. / Hiperhomocysteinemia powiklana zawalem miesnia sercowego oraz zakrzepica zyly wrotnej--opis przypadku.

Hyperhomocysteinemia (HHcy) can be associated with deficiency of group B vitamins and folic acid. HHcy might also results from renal insufficiency, diabetes, hypothyreosis or malignant diseases. In same cases HHcy is connected with mutations of genes involved in its metabolism. HHcy causes the increased risk of arterial and vein thrombosis. In this paper we show case report of woman with HHcy, who developed several complications, probably because of HHcy. This patient in the age of 38 and 44 years developed twice myocardial infarction, whereas in the age of 48 she suffered from portal vein thrombosis. According to documentation, the level of cholesterol has never been elevated, however HHcy was observed. During diagnostic process, the primary and secondary causes of HHcy were assessed. Mutations of genes involved in Hcy metabolism were also assessed. We did not find any mutation in protein products of methylenotetrahydrofolate reductase (MTHFR) or cystationine beta-synthase (CBS). The patient was treated with the use of folic acid, vitamin B12 and B6 supplementation, and normalization of Hcy level was received. This case report underline, how important role in the case of HHcy play vitamin supplementation. The early treatment of HHcy might limit thromboembolic complication.

[Morgagni-Adams-Stokes after adenosine injection in a patient with WPW syndrome--a case report]. / Zespól Morgagni-Adams-Stockesa po wstrzyknieciu adenozyny u pacjentki z zespolem WPW.

A case of a 16-year-old girl with left sided accessory pathway is presented. Following adenosine-induced termination of atrio-ventricular reentrant tachycardia the patient developed polymorphic ventricular tachycardia followed by preexcited atrial fibrillation with very rapid ventricular response and syncope. Arrhythmia was terminated by amiodarone infusion. Potential complications after adenosine injection are discussed.

[Portal vein thrombosis in patients with thrombophilia--own observations]. / Zakrzepica ukladu zyly wrotnej u chorych z trombofilia-- obserwacje wlasne.

Portal vein thrombosis is one of the main prehepatic causes of portal hypertension. The most frequent causes of thrombosis in this localization, apart from hepatic cirrhosis, are the following: acute inflammatory diseases and abdominal cancers, traumas, proliferative diseases of the hematopoietic system. In recent years attention was given to disorders in hemostasis, such as thrombophilia, in the course of which thrombosis development is particularly common. The authors present 10 patients after an incident of portal vein thrombosis, in which primary hepatic pathology was excluded and tests directed at thrombophilia were performed. In seven patients abnormalities in the examined parameters were found, and what is more, in two cases they had a complex character and involved more than one parameter. In five patients hyperhomocysteinemia was found. Among them, in two patients there was also a decreased protein S activity and in one of them there was also APC-resistance. In the next two patients there were abnormalities in one of the examined parameters - APC-resistance. Hyperhomocysteinemia was found in all patients with idiopathic thrombosis, and in one of them there were concurrent changes in protein S activity and APC-resistance. In patients with the history of portal vein thrombosis diagnostics of thrombophilia should be performed.

[Negative D-dimers and exclusion of venous thromboembolism--own experience]. / Ujemny dimer D a wykluczenie zylnej choroby zakrzepowo-zatorowej--doswiadczenia wlasne.

The assessment of D-dimer concentration has become essential step during diagnostic algorithm of venous thromboembolism (VTE). This test characterizes high sensitivity but limited specificity. Negative D-dimer with high probability excludes VTE. The aim of this study was to assess the percentage of patients treated in Department of Internal Medicine, Endocrinology and Haemostatic Disorders, Medical University of Gdanisk, who in spite of clinical signs of VTE showed normal D-dimer level. Between 2000 and 2004 in our department 57 cases with recent deep vein thrombosis (DVT) were diagnosed, in 2 cases with co-existence of pulmonary embolism (PE). The D-dimer concentration was assessed in patients' plasma with the use of immunoturbidometry. Between 57 cases with VTE, 7 patients (12%) showed normal D-dimer level (<500 microg/ml). This group consisted of 4 men and 3 women, aged from 40 to 82 years (the mean age of 58 years). In all 7 cases DVT was diagnosed, in 2 patients with concomitent PE. The final diagnosis was confirmed by compression ultrasonography and pulmonary scintigraphy. Our analysis underlines the observation that occurrence of VTE and negative d-dimer concentration is possible and may probably be related to methodological limitations. However, the lack of increase of D-dimer could also be caused by fibrinolysis alteration.

[Macrocytic megaloblastic anaemia in a patient with Helicobacter pylori infection]. / Niedokrwistosc makrocytarna megaloblastyczna u chorego z zakazeniem Helicobacter pylori.

We present 62 yrs old patient in whom megaloblastic anaemia due to vitamin B12 depletion was caused by Helicobacter pylori infection. An eradication treatment with the vitamin B12 supplementation within 7 days resulted in withdrawal of the abnormalities in the blood smear. The inflammation of gastric mucosa with intestine metaplasia is still observed. According to the letters these changes may persist up to 2-3 years after treatment ending.

[Serum homocysteine, vitamin B12 and folic acid concentrations in patients with alcoholic liver cirrhosis]. / Stezenie homocysteiny, witaminy B12 i kwasu foliowego w surowicy u chorych z alkoholowa choroba watroby.

The aim of the work was to establish serum homocysteine, vitamin B12 and folic acid concentrations in patients with alcoholic liver disease. Mentioned above vitamins are enzymatic cofactors for metabolic changes of homocysteine. It is a common fact that alcoholics often present with avitaminosis. Additionally, damaged liver worsens this pathology what can negatively influence metabolism of homocysteine. 40 patients--(mean age 52.7 years) and 40 healthy individuals (mean age 50.3 years) were examined. Hyperhomocysteinemia (concentration > 12 mmol//l) was stated in 50% of the patients and mean homocysteine concentration was statistically significantly higher if compared to the controls (13.29 +/- 8.16 vs 11.03 +/- 1.6 mmol/l p < 0.05). In the female patients homocysteine concentration was significantly higher than in the healthy controls (14.6 +/- 10.63 vs 10.73 +/- 1.37 mmol/l p < 0.001). A negative correlation between homocysteine concentration and folic acid concentration in the group of the patients with hyperthomocysteinemia was observed (r = -0.88, p < 0.001) and among all the patients (r = -0.312, n.s.). Vitamin B12 levels were significantly higher in the group of patients than in the controls (659.43 +/- 489.27 vs 384.44 +/- 145.93 p < 0.001) what is consistent with the data from the literature. A positive correlation between mean homocysteine concentration, age and platelet count of the examined patients was stated (r = 0.350, p < 0.05, r = 0.508, p < 0.001). On the basis of the obtained results one can conclude that hyperthomocysteinemia is often established in alcoholic liver disease. Partially, low folic acid concentration is responsible for this fact. In theoretical deliberation one should consider estimation of betaine metylotransferasis levels--the enzyme which is responsible for homocysteine metabolism in the liver.