Controlling a new plasma regime.

Success of the UK's Spherical Tokamak for Energy Production (STEP) programme requires a robust plasma control system. This system has to guide the plasma from initiation to the burning phase, maintain it there, produce the desired fusion power for the desired duration and then terminate the plasma safely. This has to be done in a challenging environment with limited sensors and without overloading plasma-facing components. The plasma parameters and the operational regime in the STEP prototype will be very different from tokamaks, which are presently in operation. During fusion burn, the plasma regime in STEP will be self-organizing, adding further complications to the plasma control system design. This article describes the work to date on the design of individual controllers for plasma shape and position, magneto hydrodynamic instabilities, heat load and fusion power. Having studied 'normal' operation, the article discusses the philosophy of how the system will handle exceptions, when things do not go exactly as planned. This article is part of the theme issue 'Delivering Fusion Energy - The Spherical Tokamak for Energy Production (STEP)'.

Effect of kraft pulp inclusion in calf starter on performance, health, and plasma concentration of glucagon-like peptide 2 in calves.

Kraft pulp (KP), an intermediate product obtained when wood chips are converted to paper, contains highly digestible fiber. This study evaluated the effect of KP inclusion in calf starters on growth performance, health, and plasma glucagon-like peptide 2 (GLP-2) concentration in calves. Twenty-five Holstein heifer calves were raised on a high plane of nutrition program using milk replacer containing 29% crude protein and 18% fat until 49 d after birth, and were fed calf starters containing KP at 0 (CON; n = 14) or 12% (KPS; n = 11) on a dry matter basis. All calves were fed the treatment calf starters and timothy hay ad libitum. Blood was collected at 4, 14, 21, 35, 49, 70, and 91 d after birth. Dry matter intake (DMI) of milk replacer and hay was not affected by treatment, whereas calf starter DMI was lower for KPS (0.93 kg/d) than for CON (1.03 kg/d). Higher neutral detergent fiber (NDF) content in KPS (31.7%) than in the CON starter (22.1%) resulted in higher NDF intake for KPS (0.55 kg/d) than for CON (0.47 kg/d). However, the consumption of starch was lower for KPS (0.29 kg/d) than for CON (0.33 kg/d). Despite the lower starter intake for KPS, body weight and average daily gain did not differ between treatments. No significant difference was observed in the plasma concentrations of metabolites, except for ß-hydroxybutyrate (BHB); BHB concentration was lower for KPS (216 µmol/L) than for CON (257 µmol/L). The area under the curve for plasma GLP-2 concentration was higher for KPS (54.1 ng/mL × d) than for CON (36.0 ng/mL × d). Additionally, the fecal score postweaning (1.19 and 1.48 for KPS and CON, respectively) and the number of days that calves developed diarrhea throughout the experimental period (2.50 d and 8.10 d for KPS and CON, respectively) were lower for KPS than for CON. These results indicate that feeding KP reduces the severity and frequency of diarrhea without adversely affecting growth performance. This could be attributed to the increased plasma GLP-2 concentration induced by higher NDF intake.

Enhancing Removal of Pollutants by Combining Photocatalysis and Photo-Fenton Using Co, Fe-Doped Titanate Nanowires.

Aiming to improve their photocatalytic performance, titanate nanowires (TNW) were modified by Fe and Co (co)-doping, FeTNW, CoTNW and CoFeTNW samples, using a hydrothermal methodology. XRD characterization agrees with the existence of Fe and Co in the lattice structure.and the existence of Co2+ together with the presence of Fe2+ and Fe3+ in the structure was confirmed by XPS. The optical characterization of the modified powders shows the impact of the d-d transitions of both metals in the absorption properties of TNW, mainly in the creation of additional 3d energetic levels within the prohibited zone. The effect of the doping metal(s) in the recombination rate of photo-generated charge carriers suggests a higher impact of Fe presence when compared to Co. The photocatalytic characterization of the prepared samples was evaluated via the removal of acetaminophen. Furthermore, a mixture containing both acetaminophen and caffeine, a well-known commercial combination, was also tested. CoFeTNW sample was the best photocatalyst for the degradation of acetaminophen in both situations. A mechanism for the photo-activation of the modified semiconductor is discussed and a model proposed. It was concluded that both Co and Fe are essential, within the TNW structure, for the successful removal of acetaminophen and caffeine.

Electro-optic Bdot probe measurement of magnetic fluctuations in plasma.

We propose a combined use of a Pockels electro-optic sensor with a pickup loop coil (Bdot probe) for the measurement of magnetic fluctuations in plasmas. In this method, induced fluctuating voltage on the coil loop is converted into an optical signal by a compact electro-optic sensor in the vicinity of the measurement point and is transferred across optical fiber that is unaffected by electric noise or capacitive load issues. Compared with conventional Bdot probes, the electro-optic Bdot probe (1) is electrically isolated and free from noise pickup caused by the metallic transmission line and (2) can be operated at a higher-frequency range because of the smaller capacitance of the operation circuit, both of which are suitable for many plasma experiments. Conversely, the sensitivity of the current electro-optic Bdot probe arrangement is still significantly lower than that of conventional Bdot probes. A preliminary measurement result with the electro-optic Bdot probe showed the detection of a magnetic fluctuation signal around the cyclotron frequency range in the RT-1 magnetospheric plasma experiment.

Primary cutaneous CD30+ anaplastic large-cell lymphoma with generalized skin involvement and involvement of one peripheral lymph node, successfully treated with low-dose oral etoposide.

Primary cutaneous CD30+ anaplastic large-cell lymphoma (PCALCL) in adults is rare, and the prognosis is generally excellent. Multifocal PCALCL tends to relapse after multiagent chemotherapy and is generally considered more prone to progress to extracutaneous involvement than is the localized disease. We report a 43-year-old woman with PCALCL who had generalized skin involvement accompanied by involvement of one peripheral draining lymph-node region. Although the disease relapsed after multiagent chemotherapy regimens, the disease was successfully treated with low-dose etoposide. We reviewed the previously reported cases of PCALCL treated with low-dose etoposide. We suggest that oral etoposide might be a useful effective treatment for treatment of relapsed multifocal PCALCL.

Virulence factors of avian pathogenic Escherichia coli strains isolated from chickens with colisepticemia in Japan.

The virulence factors of avian pathogenic Escherichia coli (APEC) isolated in Japan were investigated. Serogroups O, serotypes K1 and K5, and genes cva C, iss, iutA, papA, tsh, and usp, which have been thought to be related to virulence, were examined for their association with E. coli strains isolated from diseased and healthy chickens. The frequently recognized serogroups O1, O2, and O78 were found in 56 of 125 (44.8%) strains of diseased chickens (APEC) versus 13 of 100 (13.0%) strains of healthy chickens (commensal E. coli), a significant difference at risk ratio < 0.01. Although iss, iutA, and tsh were widely distributed in the APEC irrespective of O serogroup, papA, usp, and the K1 serotype were detected in serogroup O2 of APEC. The kfiD gene related to the K5 capsule and VT, LT, and ST genes related to exotoxins were not detected in any strains examined.

Electro-optic probe measurements of electric fields in plasmas.

The direct measurements of high-frequency electric fields in a plasma bring about significant advances in the physics and engineering of various waves. We have developed an electro-optic sensor system based on the Pockels effect. Since the signal is transmitted through an optical fiber, the system has high tolerance for electromagnetic noises. To demonstrate its applicability to plasma experiments, we report the first result of measurement of the ion-cyclotron wave excited in the RT-1 magnetosphere device. This study compares the results of experimental field measurements with simulation results of electric fields in plasmas.

Cytomegalovirus infection in patients with sepsis due to bloodstream infections: lower risk and better outcomes in new versus already hospitalised intensive care unit admissions.

Few studies have examined cytomegalovirus (CMV) reactivation exclusively in immunocompetent patients with sepsis due to bloodstream infections. In a cohort of CMV-seropositive critically ill otherwise non-immunosuppressed patients with sepsis due to bloodstream infection, weekly testing for CMV viraemia was performed. Outcomes were assessed at 30 days or until death/discharge from the intensive care unit (ICU). CMV viraemia developed in 20% (20/100) of the patients. Age (P=0.044) and blood transfusions (P=0.022) were significantly associated with CMV viraemia. There was no difference in the primary endpoint (mortality and/or multi-organ failure) between patients with and without CMV viraemia (P=0.49). However, CMV viraemia was associated with significantly fewer ICU-free days (P=0.023) and fewer ventilator-free days (P=0.031). Patients hospitalised in the ICU for more than 48 hours prior to the onset of bloodstream infection were more likely to develop CMV viraemia (P=0.006), have high-grade viraemia (P=0.010), and fewer ICU-free days (P=0.018) and ventilator-free days (P=0.029) than those admitted within 48 hours of bloodstream infection. Thus, CMV reactivation was associated with fewer ICU- and ventilator-free days, however overall mortality was not affected. Patients already in the ICU at the onset of sepsis had higher risk of CMV reactivation and worse outcomes than new ICU-bound patients suggesting that a targeted approach for interventions for CMV could conceivably be directed towards those with a more protracted course of illness.

Differences related to the production of arachidonic acid between collagen- and thrombin-stimulated human platelets.

The effects of collagen and thrombin on the liberation of free arachidonic acid were investigated in human platelets by fluorometric high-performance liquid chromatography. Collagen induced a concentration-dependent increase in the extent of platelet aggregation, as well as an accumulation of arachidonic acid in human platelets. By contrast, thrombin effectively provoked a potent aggregation at relatively low concentration without any accumulation of free arachidonic acid, although the accumulation of arachidonic acid was detected at a high concentration of thrombin (> 0.1 U/ml) that induced full aggregation. The selective liberation of arachidonic acid was found in thrombin-stimulated platelets. Non-selective liberation of fatty acids occurred in platelets that had been stimulated with a high concentration of collagen (10 micrograms/ml), as well as in platelets stimulated with A23187. The net amount of free arachidonic acid in collagen-stimulated platelets was estimated by use of eicosatetraenoic acid (ETYA), which is an inhibitor of both cyclooxygenase and lipoxygenase. ETYA markedly potentiated the accumulation of free arachidonic acid in collagen-stimulated platelets without changing the amounts of other fatty acids in the cell.

Genotypic variations of Shiga toxin-converting phages from enterohaemorrhagic Escherichia coli O157: H7 isolates.

Pulsed-field gel electrophoresis (PFGE) analysis revealed that enterohaemorrhagic Escherichia coli (EHEC) O157:H7 strains had considerable variations in their genomes. This study investigated whether or not the molecular profile of Shiga toxin (Stx) 1- and Stx2-converting phages isolated from EHEC O157:H7 strains, derived from various sources in the USA and Japan, corresponded to the variations of host strains' genotypes as determined by PFGE. A total of 51 Stx-converting phages including 12 Stx1-converting phages and 37 Stx2-converting phages was isolated from seven USA isolates and 20 Japanese isolates. The average Dice coefficient values showed 44% similarity between phage DNAs in Stx2-converting phages digested with SmaI and 55% in Stx1-converting phages digested with HindIII, indicating considerable variation among phage DNA. In particular, restriction fragment length polymorphism (RFLP) patterns of Stx2-converting phage DNA varied according to the PFGE type of their host strain, which suggests that the phage genomes have altered their genotypic characteristics with those of host genomes. However, there are several exceptions: the RFLP patterns of some Stx2-converting phages were quite similar irrespective of the different genotypes of the host strains, indicating that horizontal transfer of Stx2-converting phage may also occur under some circumstances.

An investigation of gram-negative tannin-protein complex degrading bacteria in fecal flora of various mammals.

Gram-negative tannin-protein complex degrading bacteria (T-PCDB) were first isolated from animals except for the koala. The occurrence of T-PCDB in feces of 15 species of mammals with different feeding habits was investigated. T-PCDB occurred in 7 of 54 horses but they could not be isolated from other mammals tested. These T-PCDB comprised less than 0.1% of the facultative anaerobic microflora in horse feces and it was much less than that previously reported in koala feces ( > 60%). A total of 7 T-PCDB fecal isolates showed a range of phenotypic diversities. They were all Gram-negative rods of various sizes and shapes including coccoidal rod. Although all produced tannase, no strain showed to have gallate decarboxylase. A total of 23 representative strains belonging to the family Pasteurellaceae were also tested for tannase production. Two strains, Haemophilus actinomycetemcomitans NIAH-10202T and Haemophilus segnis NIAH-10183T which were isolated from human oral cavity were detected positive for tannase.

Biochemical and antigenical characterization of tannin-protein complex degrading enterobacteria isolated from koalas, Phascolarctos cinereus.

Biochemical and antigenical characteristics of tannin-protein complex degrading enterobacteria (T-PCDE) isolated from Koalas, Phascolarctos cinereus, were investigated. T-PCDE had a specific profile of characteristics, and T-PCDE was distinguished from those of 12 type strains of Enterobacteriaceae used.

Microflora of the pouch of the koala (Phascolarctos cinereus).

Microflora of the pouch epithelium of 17 female koalas (Phascolarctos cinereus) were examined in relation to their current reproductive status and recent reproductive history. No microbial growth was observed in pouch swabs from 13 of 17 (76%) koalas, including four females without young, seven with pouch young and two with back young (i.e. permanently emerged from the pouch). Growth of bacteria or yeasts was observed in pouch swabs from four koalas, each of which had experienced mortality of its pouch young during the current breeding season. Seven species of microorganisms were isolated, including Pseudomonas aeruginosa, Serratia marcescens and Enterococcus faecalis. Based on the absence of microflora in the majority of females examined, we propose that the pouch epithelium normally provides a hostile environment for microbial colonization.

Serological assessment of chlamydial infection in the koala by a slide EIA technique.

A rapid and simplified slide enzyme immunosorbent assay (EIA) was developed for the diagnosis of chlamydial infection in the koala. HeLa 229 cells infected with koala strain Chlamydia psittaci were fixed on the surface of multiwell slides and used as the antigen. The assay consisted of first reacting koala antiserum with the fixed C psittaci antigen, followed by reaction with biotinylated rabbit anti-koala IgG, ABC reagent and substrate. The chlamydial EIA antibody titres obtained were compared with those of a complement fixation (CF) test using koala strain C psittaci as antigen. Of 35 koala sera tested, 16 CF positive sera (greater than or equal to 1:8) also had a positive titre (greater than or equal to 1:200) in the slide EIA test (sensitivity 93.8%, 15/16). Nineteen CF negative sera were also negative in the slide EIA (specificity 100%, 19/19). Sixty-eight samples of koala blood were collected by ear-prick using a sampling paper method and were assayed by both tests. Sensitivity of the slide EIA was 100% (15/15) and specificity of the test was 96.2% (51/53). To simplify the slide EIA for use as a practical screening test, a 3-point serum dilution series (1:100, 1:200, 1:400) was used. This 3-point slide EIA was compared with the CF test using sheep strain chlamydial antigen. Thirty-nine sera were assayed by both tests. The sensitivity of the 3-point method was 85.7% (6/7) and the specificity was 71.9% (23/32) as compared with the sheep antigen CF test.(ABSTRACT TRUNCATED AT 250 WORDS)

[Isolation of enterohemorrhagic Escherichia coli (O157:H7) by an immunomagnetic separation method].

Three sporadic cases of enterohemorrhagic Escherichia coli (EHEC) O157 infection which occurred in Kanagawa in 1996 were investigated. In an attempt to determine sources of the infection, a novel method of immunomagnetic separation (IMS) was employed to isolate the bacterium from feces, foods, and other associated items. In the first case, strains of EHEC O157:H7 producing Vero toxin (VT) 2 were isolated from both feces of the patient and suspected food (cattle liver) kept at a restaurant, and the strains were found to be genotypically identical through an analysis of pulsed-field gel electrophoresis (PFGE). Subsequent investigation in the meat processing store, from which the above cattle liver had been retailed to the restaurants revealed that the store was contaminated with EHEC O157:H7 producing both VT1 and VT2. In the second case, a strain isolated from the patient was EHEC O157:H7 producing both VT1 and VT2 while strains isolated from the patient's family (without apparent symptom) and the suspected facility were O137:NM producing VT2. PFGE analysis indicated that the latter two strains were genotypically identical, suggesting that the facility thus contaminated with EHEC O157 caused the infection in question. In the third case, EHEC O157:NM producing VT2 was isolated from 4 out of 7 family members including the patient, and these strains were found to be genotypically identical by subsequent PFGE analysis. Source of the infection was, however, not determined due to lack of suspected food items. In this context, four slaughterhouses in Kanagawa Prefecture were investigated for presence of EHEC O157. As a result, strains of EHEC O157:H7 producing VT1 and VT2 were isolated from the contents of cattle's distal colon and surface of the skinned carcasses. Additional attempt was also made to determine a possibility of river water being contaminated with EHEC O157. The bacterium was, however, not isolated from water samples collected from 4 major rivers in the prefecture (at 10 collecting sites). Experiments were undertaken in order to evaluate the use of IMS in isolation of EHEC O157 from food items, with different pre-enrichment media and conditions. The results indicated that pre-enrichment by trypticase soy broth at 36 degrees C for 6 h followed by inoculating onto sorbitol MacConkey agar plate containing cefixime and tellurite was most appropriate to isolate EHEC O157 strains.