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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biocompatibility of two different titanium alloys, Ti-6Al-4V ELI and Ti-5Al-2, 5Fe, and pure titanium were evaluated. The results were as follows: 1) Titanium alloys were implanted into the dorsal subcutaneous tissues of the Hartley guinea-pig for 12 weeks, immersed in calf serum or in Ringer's solution for 8 weeks. The surface changes of the titanium alloys were observed by SEM and the chemical composition was analyzed by XMA. No evident surface changes were found. 2) Three hundred mg, 200 mg and 100 mg of the powders of the tested materials were immersed in 2ml of Eagle's MEM, incubated for 1-7 days, 8-21 days and 22-70 days at 37 C degrees. The amount of metallic elements dissolved in the solutions was measured by ICP and AAS. The detected corrosion rates of V and Al contained in the solution, in which Ti-6Al-4V ELI 100 mg was immersed for 1-7 days, were 194.3 +/- 17.6 and 73.0 +/- 28, 1 pg/mg alloy/day, respectively. V was released more than Al. The amount of Ti was below the detectable limit. The solution Ti-5Al-2.5 Fe 100 mg immersed for 1-7 days contained 31.9 +/- 34.4 pg/mg alloy/day Fe and 25.7 +/- 6.3 pg/mg alloy/day Al. Only in the solution 300 mg immersed for 1-7 days was Ti detected at 1.4 pg/mg alloy/day. 3) By the bacterial mutation assay of Salmonella typhimurium TA 98, Salmonella typhimurium TA 100 and Escherichia coli WP2 uvrA, the solutions, in which the tested materials were immersed, were not found to be mutagenic. 4) By the UDS assay, the grain counts on autoradiography with the solutions, in which the tested materials were immersed, were not greater than the negative control. The results suggest an excellent corrosion resistance of the titanium alloys. Mutagenicity was negative by these mutation assays, indicating that the tested alloys and pure titanium are safe for humans and animals.
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PMID:[Study on biocompatibility of titanium alloys]. 279 96

Cerebral blood volume (CBV) and intracranial (ICP) were examined in dogs during 3.5 h anesthesia with isoflurane (1.4% expired) or fentanyl (continuous intravenous infusion), and after decreasing the concentration of isoflurane to less than 0.15% expired or discontinuing administration of fentanyl. Isoflurane (1.4%) increased CBV 9-11% for greater than 3 h but increased ICP for only the first 21.7 +/- 1.4 min (mean +/- SEM). Fentanyl decreased CBV 7-10% for greater than 3 h but decreased ICP for only the first 20.3 +/- 2.7 min. Because both halothane or enflurane increase ICP for greater than 3 h in this model, both isoflurane or fentanyl may be preferred to halothane or enflurane for patients at risk for increased ICP.
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PMID:Relationship between cerebral blood volume and CSF pressure during anesthesia with isoflurane or fentanyl in dogs. 673 13

Aim of the current study was to investigate the influence of intracranial hypertension on the resolution of vasogenic brain edema following intracerebral hemorrhage. An intracerebral hematoma was induced by 500 microliters of blood injected into the left frontal lobe of rabbits (n = 25). Na(+)-fluorescein (MW376) and Texas-Red-albumin (MW67.000) were administered intravenously as edema markers. By using a closed cranial window for superfusion of the brain surface and a ventriculo-cisternal perfusion the clearance of both fluorescence markers was measured in the CSF-effluates up to 8 hours using spectrophotometry. ICP was adjusted between 2-6 mmHg (low pressure, n = 10), 8-12 mmHg (moderate pressure, n = 10) or 14-20 mmHg (high pressure, n = 5). In all groups Na(+)-fluorescein started to accumulate at 60 min after induction of the hematoma in the subarachnoid space, while at 90 min in the ventricular system. In the low intracranial pressure group Na(+)-fluorescein (mean +/- SEM) in the ventricular system amounted to 1.47 +/- 0.42 nmol as compared to 1.34 +/- 0.41 nmol in the moderate, or 0.38 +/- 0.11 nmol in the high intracranial pressure group. In the subarachnoid space the marker reached 1.96 +/- 0.57 nmol, 4.15 +/- 1.28 nmol, or 0.96 +/- 0.32 nmol, respectively. In conclusion, the data demonstrate that vasogenic edema induced by an intracerebral hematoma is cleared into both CSF compartments, albeit with delay into the ventricular system. Edema resorption occurred earlier and to a higher extent into the subarachnoid space as compared to the ventricular system. Further, edema resorption is influenced by the actual intracranial pressure, with marked inhibition by a high intracranial pressure.
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PMID:Intracranial hypertension influences the resolution of vasogenic brain edema following intracerebral hemorrhage. 1145 77

The chemistry of sulfide mine tailings treated with potassium ferrate (K2FeO4) in aqueous slurry has been investigated. The reaction system is believed to parallel a geochemical oxidation in which ferrate ion replaces oxygen. This chemical system utilized in a pipeline (as a plug flow reactor) may have application eliminating the potential for tailings to leach acid while recovering the metal from the tailings. Elemental analyses were performed using an ICP spectrometer for the aqueous phase extract of the treated tailings; and an SEM-EDX for the tailing solids. Solids were analyzed before and after treatments were applied. ICP shows that as the mass ratio of ferrate ion to tailings increases, the concentration of metals in the extract solution increases; while EDX indicates a corresponding decrease in sulfur content of the tailing solids. The extraction of metal and reduction in sulfide content is significant. The kinetic timeframe is on the order of minutes.
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PMID:Rapid oxidation of sulfide mine tailings by reaction with potassium ferrate. 1281 Mar 18

The concentrations of manganese, copper, and zinc in cerebrospinal fluid (CSF) from patients with multiple sclerosis (MS) and patients with no known neurological disease (control group) were measured. Manganese and copper levels were determined by two different analytical methods: atomic absorption spectrometry (AAS) and high-resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS), whereas zinc levels were determined by HR-ICP-MS only. Manganese levels (mean+/-SEM) were significantly decreased in the CSF of MS patients (1.07+/-0.13 microg/L, ICP-MS; 1.08+/-0.11 microg/L, AAS) compared to the levels in the control group (1.78+/-0.26 microg/L, ICP-MS; 1.51+/-0.17 microg/L, AAS). Copper levels were significantly elevated in the CSF of MS patients (10.90+/-1.11 microg/L; ICP-MS, 11.53+/-0.83 microg/L, AAS) compared to the levels in the control group (8.67+/-0.49 microg/L, ICP-MS; 9.10+/-0.62 microg/L, AAS). There were no significant differences between the CSF zinc levels of MS and control patients. The physiological basis for the differences in manganese and copper concentrations between MS patients and controls is unknown, but could be related to alterations in the manganese- containing enzyme glutamine synthetase and the copper-containing enzyme cytochrome oxidase.
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PMID:Manganese, copper, and zinc in cerebrospinal fluid from patients with multiple sclerosis. 1283 84

A methodological approach is used to characterize arsenic pollution in three soils and to determine arsenic speciation and association with solid phases in three polluted soils. HPLC-ICP-MS was used for arsenic speciation analysis, SEM-EDS and XRD for physical characterization of arsenic pollution, and sequential chemical extractions to identify arsenic distribution. Arsenic was concentrated in the finest size fractions also enriched in iron and aluminium. Total arsenic concentrations in soils are close to 1%. Arsenic was mainly present as arsenate, representing more than 90% of total arsenic. No crystallised arsenic minerals were detected by XRD analysis. SEM-EDS observations indicated arsenic/iron associations. Modified Tessier's procedure showed that arsenic was mainly extracted from amorphous iron oxide phase. The results of this methodological approach lead to predict the formation of iron arsenates in the case of one of the studied soils while arsenic sorption on iron amorphous (hydr)oxides seemed to be the determinant in the two other soils.
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PMID:A methodological approach for the identification of arsenic bearing phases in polluted soils. 1286 Jan 2

Pure calcium carbonate (calcite and aragonite) solid materials of different particle size (100-200 microm fragments and millimeter-sized single crystals) were interacted with Pb in aqueous solutions at room temperature under atmospheric PCO2. In the case of the micrometer-sized samples, the macroscopic investigation using a batch-type treatment procedure (solutions between 10 and 1000 mg/L Pb) and ICP-AES, SEM-EDS, and powder-XRD showed that the metal is readily removed from the aqueous media by both materials and indicated the sorption processes (mainly surface precipitation leading to overgrowth of cerussite and hydrocerussite crystals) taking place in parallel with surface dissolution processes. The various processes occurring at the calcium carbonate solid-water interface were clearly distinguished and defined in the case of the millimeter-sized samples interacted with 1000 mg/L Pb using a combination of wet-chemical, in-situ (AFM) and ex-situ (AFM, SEM) microscopic, and surface spectroscopic (XPS, 12C-RBS) techniques. The in-situ AFM data revealed the dissolution processes on the surface of the calcium carbonates and the simultaneous heterogeneous nucleation of lead carbonate phases and confirmed the secondary dissolution of lead carbonate crystals grown epitaxially from the initial nuclei. The XPS spectra confirmed that adsorption of Pb occurs simultaneously to dissolution at short interaction times (less than approximately 10 min, prior to precipitation-nucleation/crystal growth) in the case of both CaCO3 polymorphs and that the calcite surface with adsorbed Pb may have an aragonite-type character. The 12C-RBS spectra indicated that absorption (incorporation of Pb2+ ions) also takes place in parallel at the surface layers of the calcium carbonates, resulting in formation of solid solutions.
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PMID:Interaction of calcium carbonates with lead in aqueous solutions. 1296 81

Bioactive glass fibers are attractive materials for use as tissue-engineering scaffolds and as the reinforcing phase for resorbable bioactive composites. The bioactivity of S520 glass fibers (52.0 mol % SiO(2), 20.9 Na(2)O, 7.1 K(2)O, 18.0 CaO, and 2.0 P(2)O(5)) was evaluated in two media, simulated body fluid (SBF) and Dulbecco's modified Eagle's medium (DMEM), for up to 20 days at 37 degrees C. Hydroxyapatite formation was observed on S520 fiber surfaces after 5 h in SBF. After a 20-day immersion, a continuous hydroxyapatite layer was present on the surface of samples immersed in SBF as well as on those samples immersed in DMEM [fiber surface area to solution volume ratio (SA:V) of 0.10 cm(2)/mL]. Backscattered electron imaging and EDS analysis revealed that the hydroxyapatite layer formation was more extensive for samples immersed in SBF. Decreasing the SA:V ratio to 0.05 cm(2)/mL decreased the time required to form a continuous hydroxyapatite surface layer. ICP was used to reveal Si, Ca, and P release profiles in DMEM after the 1st h (15.1, 83.8, and 29.7 ppm, respectively) were similar to those concentrations previously determined to stimulate gene expression in osteoblasts in vitro (16.5, 83.3, and 30.4 ppm, respectively). The tensile strength of the 20-microm diameter fibers was 925 +/- 424 MPa. Primary human osteoblast attachment to the fiber surface was studied by using SEM, and mineralization was studied by using alizarin red staining. Osteoblast dorsal ruffles, cell projections, and lamellipodia were observed, and by 7 days, cells had proliferated to form monolayer areas as shown by SEM. At 14 days, nodule formation was observed, and these nodules stained positive for alizarin red, demonstrating Ca deposition and, therefore mineralization.
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PMID:In vitro bioactivity of S520 glass fibers and initial assessment of osteoblast attachment. 1451 88

The kinetics of pyrolysis of electronic packaging material are investigated under various heating rates (5, 10, 15, 20 K/min) in an inert atmosphere using a thermogravimetric analysis (TGA) technique. The pyrolysis characteristics of samples are examined by SEM, XRD, FTIR, ICP-MS and EA. The effect of heating condition on the surface area and pore structure of samples is discussed. Two reaction stages are involved for the pyrolysis of electronic packaging material when nitrogen is present in the carrier gas. The corresponding kinetic parameters, including activation energy, pre-exponential factor and reaction order are presented. The apparent activation energies can be divided into three groups. The results will be useful in developing pyrolysis or incineration systems for plastic waste from electronic components.
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PMID:Pyrolysis kinetics of electronic packaging material in a nitrogen atmosphere. 1456

Springtime urban road dust forms one of the most serious problems regarding air pollution in Finland. The composition and origin of springtime dust was studied in southern Finland with two different methods. Suspended particles (PM10 and TSP) were collected with high volume particle samplers and particle deposition was collected with moss bags. The composition of the PM(1.5-10) fraction was studied using individual particle analysis with SEM/EDX. The deposition in the moss bags was analysed with ICP-MS. The results showed that during the study period, approximately 10% of both PM(1.5-10) particles and the deposition originated from sanding. Other sources in the springtime PM(1.5-10) were e.g. asphalt aggregate or soil and combustion processes. It can be concluded that sanding produced a relatively small amount of particulate matter under the investigated circumstances.
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PMID:The effect of traction sanding on urban suspended particles in Finland. 1507 21


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