Residual Stress Induced by Addition of Nanosized TiC in Titanium Matrix Composite

A hot pressing process was employed to produce titanium-based composites. Nanosized TiC particles were incorporated in order to improve mechanical properties of the base material. The amount of nanosized additions in the composites was 0.5, 1.0, and 2.0 wt %, respectively. Moreover, a TiB phase was produced by in situ method during sintering process. The microstructure of the Ti–TiB–TiC composites was characterized by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) techniques. Due to the hot pressing process the morphology of primary TiC particles was changed. Observed changes in the size and shape of the reinforcing phase suggest the transformation of primary carbides into secondary carbides. Moreover, an in situ formation of TiB phase was observed in the material. Additionally, residual stress measurements were performed and revealed a mostly compressive nature with the fine contribution of shear. With an increase in TiC content, linear stress decreased, which was also related with the presence of the TiB phase.     

Aged erythrocytes exhibit decreased anion exchange

The rate of transport of [32P] phosphate into human and bovine erythrocytes and of a spin-label analogue of phosphate (Tempo-phosphate) into human erythrocytes was found to decrease with increasing erythrocyte age by 15-20% when comparing 20% most dense cells with 20% of lightest cells. The activation energy of Tempo-phosphate transport did not show significant changes upon erythrocyte aging.     

Use of spectroscopic probes for detection of reactive oxygen species

The detection and quantitation of reactive oxygen species (ROS) receives a great deal of interest because of their importance in a wide range of physiological and pathogenic events. Probe-assisted spectroscopy (electron spin resonance, spectrophotometry, fluorescence and luminescence) is the main tool for this application. This review discusses the properties of spectroscopic probes most commonly used for ROS detection and highlights their limitations in cellular systems. These include poor stability of some probes and/or products that may be subjected to cellular metabolism and lack of specificity in their reactions with oxidants or reductants. Additional problems often arise from undesired reactions of the probes and from their non-homogeneous distribution in the studied system, production of ROS by the probes themselves, perturbation of the systems under investigation by the probes, and artifacts due to the presence of ROS in the reaction medium. The limits imposed by these difficulties on the precise evaluation of the amounts and rates of formation of ROS are discussed critically.     

Intracranial infectious aneurysms: a comprehensive review

Intracranial infectious aneurysms, or mycotic aneurysms, are rare infectious cerebrovascular lesions which arise through microbial infection of the cerebral arterial wall. Due to the rarity of these lesions, the variability in their clinical presentations, and the lack of population-based epidemiological data, there is no widely accepted management methodology. We undertook a comprehensive literature search using the OVID gateway of the MEDLINE database (1950–2009) using the following keywords (singly and in combination): “infectious,” “mycotic,” “cerebral aneurysm,” and “intracranial aneurysm.” We identified 27 published clinical series describing a total of 287 patients in the English literature that presented demographic and clinical data regarding presentation, treatment, and outcome of patients with mycotic aneurysms. We then synthesized the available data into a combined cohort to more closely estimate the true demographic and clinical characteristics of this disease. We follow by presenting a comprehensive review of mycotic aneurysms, highlighting current treatment paradigms. The literature supports the administration of antibiotics in conjunction with surgical or endovascular intervention depending on the character and location of the aneurysm, as well as the clinical status of the patient. Mycotic aneurysms comprise an important subtype of potentially life-threatening cerebrovascular lesions, and further prospective studies are warranted to define outcome following both conservative and surgical or endovascular treatment.     

Viral hepatitis in health service workers in the Province of Wielkopolska

Viral hepatitis is the most frequent occupational disease in the health service workers. On the ground of epidemiological data on certifications of occupational diseases, an analysis of morbidity of viral hepatitis was performed. Among viruses that can cause occupational hepatitis there are HAV, HBV and HCV. However, occupational HDV and HGV infections are also possible. In Poland, the number of hepatitis diagnosed as occupational diseases became more stable in the years 1996-1998, whereas morbidity of hepatitis C significantly increased. Such an epidemiological situation could be observed in the area of Wielkopolska and throughout the country. In the former province of Poznań and in the present province of Wielkopolska, occupational hepatitis occurred mostly in nurses. In the nineteen sixties and seventies, the most dramatic increase in the incidence of hepatitis B was noticed in the population of nurses and midwives at the age between 21 and 30 years. This can provide evidence of especially high exposure to infectious factors in this occupational group and of high HBV infectivity. Nowadays, an average age at the time of diagnosis of hepatitis C is somewhat higher. Hepatitis C is usually recognized at the age between 30 and 39 years. A relatively low infectivity of HCV and mostly asymptomatic course of the infection, which delays diagnosis, may provide some explanations of these phenomena. The geographical distribution of stated cases of hepatitis C is difficult to predict and may suggest that some non-medical factors also play a role. Since no specific measures to prevent the incidence of hepatitis C have been developed, a good recognition of HCV reservoir in the population of health service workers (particularly nurses) is one of possible methods to improve the epidemiological situation. It might also be necessary to discuss some limitations in work ability of infected persons. In addition, good training in occupational hygiene and how to handle infectious materials is essential for health service workers.     

Lipid peroxidation and antioxidant potential in patients with cervical spinal cord injury

The aim of the study was to evaluate the intensity of oxygen-derived free radicals generation (expressed as the lipid peroxidation process), as well as antioxidant potential changes in patients with cervical spinal cord injury. Subjects in the study were 32 patients treated in the Neurosurgery and Neurotraumatology Clinic, Medical University in Bydgoszcz. Malondialdehyde (MDA) concentration and conjugated dienes (CD) level in the patients' blood plasma and erythrocytes, as well as their plasma antioxidant potential in reaction with a stable free radical--1.1-diphenyl-2-picryl-hydrazyl were assayed. Intensification of the lipid peroxidation process as well as a decrement of plasma antioxidant potential were found in the patients with cervical spinal cord injury. A strong correlation was also shown between severity of cervical spinal cord injury assessed using the ASIA impairment scale on the one hand and intensification of the lipid peroxidation process and plasma antioxidant potential decrease on the other hand.     

Combinatorial computational method gives new picomolar ligands for a known enzyme

Combinatorial small molecule growth algorithm was used to design inhibitors for human carbonic anhydrase II. Two enantiomeric candidate molecules were predicted to bind with high potency (with R isomer binding stronger than S), but in two distinct conformations. The experiments verified that computational predictions concerning the binding affinities and the binding modes were correct for both isomers. The designed R isomer is the best-known inhibitor (K(d) approximately 30 pM) of human carbonic anhydrase II.     

Phagocytosis and killing of Listeria by guinea pig macrophages and neutrophils

The rate of the phagocytosis and intracellular killing of Listeria monocytogenes by guinea pig macrophages and neutrophils in vitro was determined. The anti-bacterial activity of the phagocytes against virulent Listeria monocytogenes was compared with their activity against avirulent strain of Listeria and Proteus mirabilis. It is suggested that the contribution of the macrophages and the neutrophils to anti-bacterial protection can depend on physiological state of bacteria.     

Aging of the erythrocyte

Summary By means of the spin labelling technique changes in the microviscosity of the cell interior of density-separated bovine red blood cells were estimated. An increase in the rotational correlation time of the Tempamine spin label indicated an increase in the microviscosity of the red blood cell interior during in vivo aging. This increase is apparently due to alterations in the electrolyte content and may influence the course of diffusion-limited reactions in the cell.     

Modulation of cellular immune response by orbifloxacin in noninfected and E. coli-infected mice

The studies were conducted on noninfected and Escherichia (E) coli-infected mice treated with orbifloxacin administered orally 10 times at 24-hr intervals at a dose of 2.5 mg/kg. Orbifloxacin did not change the activity of peritoneal macrophages in noninfected mice. Administration of orbifloxacin in E. coli-infected mice modulated the effects of infection on the percentage of phagocyting macrophages, the percentage of NBT-positive cells, and nitric oxide production. Orbifloxacin did not affect the synthesis and release of interleukin-1 by macrophages. Orbifloxacin exerted a modulating effect on the subsets of lymphocytes in thymus, spleen, and mesenteric lymph node cells in noninfected and E. coli-infected mice.