Design of 3D printed stage for in situ magnetic field application in magnetic force microscopy

We propose a design of 3D printed magnetic stage that allows application of static magnetic fields during magnetic force microscopy measurements. The stage utilizes permanent magnets providing spatial homogeneous magnetic fields. The design, assembly, and installation are described. Numerical calculations of the field distribution are used to optimize the size of magnets and the spatial homogeneity of the field. The stage offers a compact and scalable design, which can be adapted as an accessory onto several commercially available magnetic force microscopy platforms. The stage's utility for in situ magnetic field application during magnetic force microscopy measurements is demonstrated on a sample of thin ferromagnetic strips.

AN IRSN CONTRIBUTION TO THE UAM PROJECT: THERMAL-HYDRAULIC AND NEUTRONIC UNCERTAINTIES PROPAGATION IN A ROD EJECTION, FIRST RESULTS

The paper presents our first results of the exercise III-I-2c from the OECD-NEA UAM-LWR benchmark intended to an elaboration of the methodology of uncertainty propagation. The considered case studied a full PWR core behavior in fast (~0.1 sec) rod ejection transient. According to the benchmark, the core represented a Hot Zero Power state. Authors used brute-force sampling propagating nuclear data and thermo-fluid uncertainties using 3D computational IRSN chain HEMERA. It couples the reactor physics code CRONOS and thermal-hydraulic core code FLICA4. The nuclear data uncertainties were represented in a form of cross sections standard deviations (in percentage of the mean cross sections values) supplied by the UAM team. In addition to the original benchmark, the study includes a case with an increased power peak by supplementary rod ejection, i.e. with higher reactivity. Both the results are similar to what we obtained in the mini-core rod ejection: the power standard deviation follows, in percentage of the mean power, the mean power curve. We split the variance with a direct calculation: once the cross sections are modified and the thermal-hydraulics inputs are kept constant, another time the contrary. The results show that uncertainties dues to nuclear data dominate over ones due to the thermal-flow area. Furthermore, the major contributors in peak-of-power variance lie in a fast group of cross sections.

High pressure torsion induced lowering of Young's modulus in high strength TNZT alloy for bio-implant applications

An exceptional combination of low Young's modulus (E ~68 GPa) and high flow strength (σ_f ~1 GPa) was achieved for a consolidated β-Ti-based metastable Ti-35Nb-7Zr-5Ta (TNZT) alloy subjected to room temperature high-pressure torsion (HPT). The mechanical properties of the alloy were studied by quasistatic nanoindentation tests at different strain rates, where a reduction in Young's modulus E ~73 GPa (N_HPT¹⁰) and E ~68 GPa (N_HPT⁴⁰) is observed together with an increase in plastic deformability (or HPT rotations). The microstructure evolution with increasing shear strain has been investigated. The stabilized bcc β-Ti phase with homogeneous nanostructure distribution was observed leading to a low Young's modulus. Severe straining causes a uniform hardness distribution without any noticeable change in the strength of the material. This study may be useful for developing excellent removable implant materials.

[Surgical antimicrobial prophylaxis: compliance to guidelines and impact of targeted information program]

OBJECTIVES

Surgical antimicrobial prophylaxis is used to decrease postoperative wound infection. We assessed the compliance to surgical antimicrobial prophylaxis guidelines in our hospital and the impact of an information program.

PATIENTS AND METHODS

Observational study of clean or clean contamined surgery, during two 3-week periods, separated by a targeted information period. The following data were collected prospectively: prophylaxis indication, antimicrobial agent, timing, dose, route and duration of prophylaxis. Chi square test was used for analysis or Fischer test when available.

RESULTS

Four hundred seventy-seven patients were enrolled - 270 and 207 for each period respectively. For both periods only 49% of prophylaxis was appropriated. When prophylaxis should be administered - 15 and 13% of patients for each period - it was antibioprophylaxy was strictly adequate with recommandations. The most common error was administration timing. Only the choice of antimicrobial agent was optimized after information period.

DISCUSSION

These results are consistent with previous studies. Information program alone have no effect on the good use of antimicrobial for surgical prophylaxis. Only a policy associating organization, restriction and education could improve practices.

Childhood leukaemia in Europe after Chernobyl: 5 year follow-up

The European Childhood Leukaemia - Lymphoma Incidence Study (ECLIS) is designed to address concerns about a possible increase in the risk of cancer in Europe following the nuclear accident in Chernobyle in 1986. This paper reports results of surveillance of childhood leukaemia in cancer registry populations from 1980 up to the end of 1991. There was a slight increase in the incidence of childhood leukaemia in Europe during this period, but the overall geographical pattern of change bears no relation to estimated exposure to radiation resulting from the accident. We conclude that at this stage of follow-up any changes in incidence consequent upon the Chernobyl accident remain undetectable against the usual background rates. Our results are consistent with current estimates of the leukaemogenic risk of radiation exposure, which, outside the immediate vicinity of the accident, was small.

Hematological malignancies in the Republic of Belarus after the Chernobyl accident

The data on post Chernobyl hematological malignancies incidence rates in Belarus are plotted. No statistically significant increase of incidence rates in childhood is observed in contrast to adults. However, no direct association of the incidence rates with a radiation factor is discovered 10 years following Chernobyl. Some indirect correlations are found like chemical pollutions and a possible synergistic effect of the latter with ionising radiation exposure may appear as risk factors for these diseases. Adults demonstrate a significant increase of morbidity due to these malignancies after the Chernobyl disaster.

Childhood leukaemia following the Chernobyl accident: the European Childhood Leukaemia-Lymphoma Incidence Study (ECLIS)

The objective of the European Childhood Leukaemia-Lymphoma Incidence Study (ECLIS) is to investigate trends in incidence rates of childhood leukaemia and lymphoma in Europe, in relation to the exposure to radiation which resulted from the accident at the Chernobyl nuclear power plant in April 1986. In this first report, the incidence of leukaemia in children aged 0-14 is presented from cancer registries in 20 European countries for the period 1980-1988. Risk of leukaemia in 1987-1988 (8-32 months post-accident) relative to that before 1986, is compared with estimated average dose of radiation received by the population in 30 geographic areas. The observed changes in incidence do not relate to exposure. The period of follow-up is so far rather brief, and the study is planned to continue for at least 10 years.

Axo-somatic contacts in the postnatal developing white rat spiral ganglion

Development of the spiral ganglion in white rats was followed during the first 2 weeks after birth and morphological characteristics of the two neuronal types (I and II) were examined. In some neurons different stages of partial degeneration leading to formation of residual bodies were found without observation of degenerated cell, supporting the idea that differentiation at this time is not associated with cell death. Contacts between cell body of type II neurons and neuronal endings is reported for the first time. Such axo-somatic contacts previously observed only in monkey and man, also exists in lower mammals.

Biochemical changes in the rat after chronic thioacetamide intoxication

Male Wistar rats were given drinking water ad libitum with 0.075% thioacetamide (TAA) for 4 weeks. TAA treatment did not affect serum aminotransferase activities and total bilirubin content. The activities of 5'-nucleotidase, K+, Na+- and Mg2+-adenosine triphosphatases in liver plasma membrane preparations were strongly depressed, while that of gamma-glutamyl transferase was considerably increased. A decline in liver microsomal cytochrome P-450 and cytochrome b5 concentrations was also recorded. In contrast, the content of reduced glutathione in liver homogenate supernatant (9000 g) increased about 2-fold. As plasma membrane associated enzymes seem to be exclusively affected, the liver plasma membrane could be involved in the pathogenesis of the TAA-induced precirrhotic liver changes.

Biochemical changes in alpha-naphthyl isothiocyanate-induced chronic cholangitis in the rat

Male Wistar rats were treated for 3 weeks with alpha-naphthyl isothiocyanate (ANIT, 5.4 mmol per kg food). Chronic necrotic cholangitis without pronounced transaminasemia and hyperbilirubinemia developed. The activity of 5'-nucleotidase in liver plasma membrane preparations was strongly depressed (3.5 times) while the activities of K+-, Na+- and Mg++-ATPases were not affected. The liver microsomal cytochrome P-450 and cytochrome b5 contents decreased. Elevation of reduced glutathione liver content after challenge with ANIT was recorded. The observed biochemical changes may be important for the pathogenesis of ANIT-induced chronic cholangitis.

Interaction between glucose diet and ethanol on rat liver microsomal induction and liver plasma membrane damage in chronic hexachlorobenzene intoxication

Male Wistar rats fed for 60 days a glucose diet containing 17.5 mmol hexachlorobenzene/kg show a less pronounced increase in serum parameters and microsomal cytochrome P-450 concentration and a lower decrease in liver plasma membrane 5'-nucleotidase, K+, Na+- and Mg++-adenosine triphosphatase activities than the controls fed standard diet + hexachlorobenzene. Addition of 10% ethanol to the drinking water eliminates the "glucose effect". The glucose diet and ethanol exert contrasting effects on microsomal enzyme induction and liver plasma membrane damage in hexachlorobenzene intoxication.

Rat liver plasma membrane damage in hexachlorobenzene intoxication and its potentiation by ethanol

Chronic feeding of male Wistar rats with food containing hexachlorobenzene (HCB) at 17.5 mmol/kg induced elevation of serum amino-transferases and bilirubin content, increase of microsomal cytochrome P-450 concentration, and decrease of 5'-nucleotidase, K+,Na+- and Mg2+-adenosine triphosphatase activities in liver plasma membrane preparations. These changes were potentiated by ethanol consumption suggesting a possible role of liver plasma membrane damage in the pathogenesis of HCB intoxication.

Progressive degeneration in the cochlear nucleus after chemical destruction of the cochlea

In the guinea pig, the organ of Corti and the spiral ganglion cells were destroyed by administering gentamicin into the inner ear. The antero-ventral cochlear nucleus (AVCN) was studied with electron microscopy 15 and 30 days after treatment. There does not seem to be a specific type of degeneration induced by the drug. For nerve terminals, a progressive degeneration occurred: after 15 days, clear and swollen boutons appeared and after 30 days an electron-dense type of degeneration was observed. The cell bodies of the AVCN did not seem altered infirming a rapid, direct or indirect, neurotoxic effect of the drug.

The effect of thioacetamide on rat liver plasma membrane enzymes and its potentiation by fasting

Thioacetamide, given intraperitoneally (1.4 mmol/kg body mass) to male Wistar rats 24 h before sacrifice promoted a marked elevation of serum aminotransferases, loss of microsomal cytochrome P-450 content and a significant reduction (about 50%) of the liver plasma membrane enzymatic activities (5'-nucleotidase; K+, Na+- and Mg2+-adenosine triphosphatases; and gamma-glutamyl transferase). Previous starvation for 48 h, immediately prior to thioacetamide administration, strongly potentiated the effects of thioacetamide on the serum, microsomal and liver plasma membrane parameters, while fasting itself did not affect them. The liver plasma membrane damage may be one of the reasons for the cell death in thioacetamide-intoxicated rat livers.

Influence of D-galactosamine and alpha-naphthylisothiocyanate on the activities of some intestinal enzymes

The activities of lactase, sucrase, maltase and gamma-glutamyl transferase (gamma-GT) were determined in homogenates of rat jejunal mucosa 24 h after acute administrations of D-galactosamine (GALN) (1.855 mmol/kg; i.p. injection) and alpha-naphthyl-isocyanate (ANIT) (0.540 mmol/kg; given by gastric tube). The animals were fasted either 24 h or 72 h prior to sacrifice. In rats fasted only 24 h, GALN treatment resulted in a pronounced decrease in lactase and in a moderate elevation of sucrase and maltase. ANIT clearly reduced lactase and, to a lesser extent, sucrase, while it increased maltase. Seventy-two hour fasting has a modifying role. All disaccharidase activities tended to decrease, except for maltase in the ANIT treated group, where an increase was recorded. gamma-GT showed no significant changes after either GALN or ANIT treatment in rats fasted 24 h. However, the 72-hour food deprivation diminished it in ANIT intoxication. It is obvious that the intestinal enzymes are influenced by the hepatic damage produced by GALN and ANIT.

Phlebotomy treatment in porphyria cutanea tarda combined with beta-thalassaemia

In 74 patients with porphyria cutanea tarda, 11 (14.9%) cases of beta-thalassaemia were found. The incidence of beta-thalassaemia in porphyrics is not greater than in non-porphyrics and it seems that beta-thalassaemia is not a factor triggering the development of porphyria cutanea tarda. The phlebotomy treatment is also a convenient method for porphyria cutanea tarda combined with beta-thalassaemia.

Rare cases of porphyria cutanea tarda associated with additional iron overload

Three rare cases are reported with porphyria cutanea tarda associated with additional iron overload – a relapse following blood transfusions, a combination with hemophilia A with massive hemorrhages and blood transfusions, and a combination with β-thalassemia. Successful treatment was carried out with phlebotomy and desferal. The role of iron overload in the pathogenesis of the disorder is discussed.

Gamma-glutamyl transferase: a sensitive marker in experimental hexachlorobenzene intoxication

The behaviour of gamma-glutamyl transferase (gamma-GT) in rat liver, serum and intestinal mucosa under the effect of hexachlorobenzene (HCB) was studied. The investigation was carried out in order to evaluate gamma-GT as a biological parameter in experimental HCG porphyria. HCB was administered by gavage at daily doses of 3.5 mmol/kg body wt for 60 days or 90 days. gamma-GT in liver homogenate progressively increased during the treatment. Following a 60-day exposure the enzymatic activity exceeded the values of the controls by more than 60 times. The rise of serum gamma-GT was more moderately expressed (5--6-fold). gamma-GT in jejunal mucosa was elevated 2-fold after a 90-day treatment. The termination of the daily intoxication reduced back to normal values the enzymatic activity in liver and in intestine as measured after 60 days from the cessation of HCB application. It can be pointed out, that gamma-GT is a sensitive and valuable marker for experimental HCB intoxication.

Genome and chromosome mutations in porphyria cutanea tarda

Spontaneous genome mutations in ten patients with porphyria cutanea tarda (PCT) amounted to 1.02% as compared to 0.36% in the control group of healthy individuals (P less than 0.01). Spontaneous structural chromosome aberrations in patients were seen in 2.39% of the examined cells versus 0.70% in the cells of controls (P less than 0.01). The increased percentage of cells with spontaneous genome and chromosome mutations in patients with PCT cannot be associated with alcohol only.