Reversible light-dependent molecular switches on Ag/AgCl nanostructures.

Nanostructured Ag/AgCl substrates were used to generate reversible and highly efficient light-dependent chemical switches based on adsorbed 4,4'-dimercaptoazobenzene (DMAB). DMAB was formed in situ via laser-induced dimerization either from 4-nitrothiophenol (4-NTP) or 4-aminothiophenol (4-ATP). The subsequent reaction pathways of DMAB, however, were quite different as monitored by surface enhanced Raman spectroscopy. In the 4-NTP/DMAB system, AgCl catalyses the reversal of the dimerization. Conversely, irradiation of adsorbed 4-ATP first generated cis-DMAB attached to the surface via two Ag-S bonds, followed by AgCl-catalysed cleavage of one Ag-S bond and cis → trans photoisomerisation of DMAB. In the dark, the trans-isomer thermally reverts to cis-DMAB. The here presented light-dark chemical switches, which work without changing other parameters (e.g., pH, anaerobic vs. aerobic), are based on the (photo)catalytic properties of the Ag/AgCl substrate and do not function on pure metal surfaces.

Phenotypic trait changes in laboratory--reared colonies of the maize herbivore, Diabrotica virgifera virgifera.

The North American and European maize pest Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) was used to assess whether conditions of the natal field, subsequent laboratory rearing, or genetic population origin affect phenotypic traits of fitness, activity, or morphometrics. Standardized laboratory bioassays with large sample sizes revealed that none of the 16 tested traits, except crawling behaviours, appeared consistently stable across all seven tested colonies. Environmental conditions in the natal field of the F 0 generation affected trait averages of the subsequently reared F 1 generation in laboratory in ca. 47% of cases, and trait variability in 67% of cases. This was apparent for fitness and morphometrics, but less obvious for activity traits. Early generation laboratory rearing affected trait averages in ca. 56% of cases: morphometrics changed; fecundity and egg survival increased from F 1 to F 2. Trait variability increased or decreased in 38% of cases. Laboratory rearing for over more than 190 generations affected the trait averages in 60% of cases, reflected by decreases in flight activity and increases in body size, weight, and fecundity to some extent. It had little effect on trait variability, especially so for morphometric variability. The genetic population origin affected average levels of 55% and variability of 63% of phenotypic traits. A comparison among D. v. virgifera studies might be difficult if they use different populations or laboratory colonies. It is advised to consider possible effects of original field conditions, laboratory rearing, and population genetics when planning comparative studies targeting fitness, activity, or morphometric questions regarding Diabrotica species.

Isotopic phonon effects in ß-rhombohedral boron--non-statistical isotope distribution.

On the basis of the spectra of IR- and Raman-active phonons, the isotopic phonon effects in ß-rhombohedral boron are analysed for polycrystalline (10)B- and (11)B-enriched samples of different origin and high-purity (nat)B single crystals. Intra- and inter-icosahedral B-B vibrations are harmonic, hence meeting the virtual crystal approximation (VCA) requirements. Deviations from the phonon shift expected according to the VCA are attributed to the anharmonic share of the lattice vibrations. In the case of icosahedral vibrations, the agreement with calculations on α-rhombohedral boron by Shirai and Katayama-Yoshida is quite satisfactory. Phonon shifts due to isotopic disorder in (nat)B are separated and determined. Some phonon frequencies are sensitive to impurities. The isotopic phonon effects yield valuable specific information on the nature of the different phonon modes. The occupation of regular boron sites by isotopes deviates significantly from the random distribution.

A comparison study of two different control criteria for the real-time management of urban groundwater works.

We present the comparison of two control criteria for the real-time management of a water well field. The criteria were used to simulate the operation of the Hardhof well field in the city of Zurich, Switzerland. This well field is threatened by diffuse pollution in the subsurface of the surrounding city area. The risk of attracting pollutants is higher if the pumping rates in four horizontal wells are increased, and can be reduced by increasing artificial recharge in several recharge basins and infiltration wells or by modifying the artificial recharge distribution. A three-dimensional finite elements flow model was built for the Hardhof site. The first control criterion used hydraulic head differences (Δh-criterion) to control the management of the well field and the second criterion used a path line method (%s-criterion) to control the percentage of inflowing water from the city area. Both control methods adapt the allocation of artificial recharge (AR) for given pumping rates in time. The simulation results show that (1) historical management decisions were less effective compared to the optimal control according to the two different criteria and (2) the distribution of artificial recharge calculated with the two control criteria also differ from each other with the %s-criterion giving better results compared to the Δh-criterion. The recharge management with the %s-criterion requires a smaller amount of water to be recharged. The ratio between average artificial recharge and average abstraction is 1.7 for the Δh-criterion and 1.5 for the %s-criterion. Both criteria were tested online. The methodologies were extended to a real-time control method using the Ensemble Kalman Filter method for assimilating 87 online available groundwater head measurements to update the model in real-time. The results of the operational implementation are also satisfying in regard of a reduced risk of well contamination.

Superconductivity in boron carbide? Clarification by low-temperature MIR/FIR spectra.

The electronic structure and phonon density of B(13)B(2) boron carbide calculated by Calandra et al (2004 Phys. Rev. B 69 224505) defines this compound as metallic, and the authors predict superconductivity with T(C)s up to 36.7 K. Their results are affected by the same deficiencies as former band structure calculations on boron carbides based on hypothetical crystal structures deviating significantly from the real ones. We present optical mid IR/far IR (MIR/FIR) spectra of boron carbide with compositions between B(4.3)C and B(10.37)C, evidencing semiconducting behaviour at least down to 30 K. There is no indication of superconductivity. The spectra yield new information on numerous localized gap states close to the valence band edge.

Isotopic effects on the phonon modes in boron carbide.

The effect of isotopes ((10)B-(11)B; (12)C-(13)C) on the infrared- and Raman-active phonons of boron carbide has been investigated. For B isotopes, the contributions of the virtual crystal approximation, polarization vector and isotopical disorder are separated. Boron and carbon isotope effects are largely opposite to one another and indicate the share of the particular atoms in the atomic assemblies vibrating in specific phonon modes. Some infrared-active phonons behave as expected for monatomic boron crystals.

Native range assessment of classical biological control agents: impact of inundative releases as pre-introduction evaluation.

Diadromus pulchellus Wesmael (Hymenoptera: Ichneumonidae) is a pupal parasitoid under consideration for introduction into Canada for the control of the invasive leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae). Since study of the parasitoid outside of quarantine was not permitted in Canada at the time of this project, we assessed its efficacy via field trials in its native range in central Europe. This was done by simulating introductory releases that would eventually take place in Canada when a permit for release is obtained. In 2007 and 2008, experimental leek plots were artificially infested with pest larvae to mimic the higher pest densities common in Canada. Based on a preliminary experiment showing that leek moth pupae were suitable for parasitism up to 5-6 days after pupation, D. pulchellus adults were mass-released into the field plots when the first host cocoons were observed. The laboratory-reared agents reproduced successfully in all trials and radically reduced leek moth survival. Taking into account background parasitism caused by naturally occurring D. pulchellus, the released agents parasitized at least 15.8%, 43.9%, 48.1% and 58.8% of the available hosts in the four release trials. When this significant contribution to leek moth mortality is added to previously published life tables, in which pupal parasitism was absent, the total pupal mortality increases from 60.1% to 76.7%. This study demonstrates how field trials involving environmental manipulation in an agent's native range can yield predictions of the agent's field efficacy once introduced into a novel area.

Comparative life tables of leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), in its native range.

Leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), is an invasive alien species in eastern Canada, the larvae of which mine the green tissues of Allium spp. This study was designed to construct and analyse life tables for leek moth within its native range. Stage-specific mortality rates were estimated for the third leek moth generation at three sites in Switzerland from 2004 to 2006 to identify some of the principle factors that inhibit leek moth population growth in areas of low pest density. The contribution of natural enemies to leek moth mortality was measured by comparing mortality on caged and uncaged leeks. Total pre-imaginal mortality on uncaged plants was 99.6%, 99.1% and 96.4% in 2004, 2005 and 2006, respectively. Variation in mortality was greater among years than among sites. Total larval mortality was greater than that in the eggs and pupae. This was due largely to the high mortality (up to 83.3%) of neonates during the brief period between egg hatch and establishment of the feeding mine. Leek moth pupal mortality was significantly greater on uncaged than on caged leeks, indicating an impact by natural enemies, and this pattern was consistent over all three years of study. In contrast, the other life stages did not show consistently higher mortality rates on uncaged plants. This observation suggests that the pupal stage may be particularly vulnerable to natural enemies and, therefore, may be the best target for classical biological control in Canada.

[Can we influence the progression of chronic kidney disease?]. / Ist die Progression der chronischen Niereninsuffizienz zu beeinflussen?

Chronic renal failure does not only involve the risk for the patient of becoming dependent on hemodialysis, but also increases the risk of premature death due to cardiovascular events. In most renal diseases, progressive chronic loss of renal function develops once a critical extent of renal damage has occurred, independent of the course of the underlying renal disease. The key factors driving the progressive loss of renal function are, apart from the underlying nephrological disease, arterial hypertension and diabetes mellitus. The loss of renal function is also promoted by other factors, such as increased intake of dietary proteins, chronic inflammation, smoking, and anemia. With the help of a multimodal therapeutic concept, the progression of chronic renal failure can be delayed effectively. This approach comprises strict blood pressure control with a target blood pressure of 130/80 mmHg in patients with micro-albuminuria and of 120/75 mmHg in patients with proteinuria of >1 g/d. The preferred drugs for the treatment of hypertension are ACE inhibitors and angiotensin receptor blockers. In diabetics with renal insufficiency, target HbA1c levels below 7% are to be aimed for. Dietary protein intake should be restricted to 0.8-1 g/kg body weight/d. Additional therapeutic targets include nicotine abstinence, early treatment of renal anemia, weight reduction, and, if indicated, lipid-lowering therapy.

Does host plant influence parasitism and parasitoid species composition in Lygus rugulipennis? A molecular approach.

Lygus Hahn plant bugs (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. European Peristenus digoneutis Loan and P. relictus Ruthe (Hymenoptera: Braconidae) are being considered for release in Canada as part of a classical biological control program for Lygus. The attractiveness of different host plants to European Peristenus has not been addressed, but may be an important consideration prior to parasitoid release. Lygus rugulipennis Poppius nymphs were collected in the Northern Temperate Atlantic (NTA) ecoregion on red clover (Trifolium pratense L.; Fabaceae) and chamomile (Matricaria recutita L.; Asteraceae), and in the Western European Broadleaf Forest (WEBF) ecoregion on red clover and alfalfa (Medicago sativa L.; Fabaceae). Parasitism levels and parasitoid species were determined using a multiplex PCR assay for P. digoneutis, P. relictus, and P. pallipes Curtis. Mean parasitism levels in L. rugulipennis were 45-49% in the NTA ecoregion and 25-32% in the WEBF ecoregion. However, in neither ecoregion were parasitism levels and parasitoid species compositions significantly different in nymphs from different host plant species. Furthermore, multiparasitism was low despite the fact that P. digoneutis and P. relictus share the same host species.

[Can the progression of chronic renal failure be delayed?]. / Kann man die Progression der chronischen Niereninsuffizienz verzögern?

Chronic renal failure does not only involve the risk for the patient of becoming dependent on hemodialysis, but also increases the risk of premature death due to cardiovascular events. In most renal diseases, progressive chronic loss of renal function develops once a critical extent of renal damage has occurred, independent of the course of the underlying renal disease. The key factors driving the progressive loss of renal function are, apart from the underlying nephrological disease, arterial hypertension and diabetes mellitus. The loss of renal function is also promoted by other factors, such as increased intake of dietary proteins, chronic inflammation, smoking, and anemia. With the help of a multimodal therapeutic concept, the progression of chronic renal failure can be delayed effectively. This approach comprises strict blood pressure control with a target blood pressure of 130/80 mmHg in patients with micro-albuminuria and of 120/75 mmHg in patients with proteinuria of >1 g/d. The preferred drugs for the treatment of hypertension are ACE inhibitors and angiotensin receptor blockers. In diabetics with renal insufficiency, target HbA1c levels below 7% are to be aimed for. Dietary protein intake should be restricted to 0.8-1 g/kg body weight/d. Additional therapeutic targets include nicotine abstinence, early treatment of renal anemia, weight reduction, and, if indicated, lipid-lowering therapy.

Pacemaker infection with propionibacterium and a nephritic sediment.

Like any other implanted foreign body, the different parts of pacemakers (pulse generator pocket, epicardial or transvenous leads) can become infected. Staphylococcus aureus and coagulase-negative staphylococci are the causative organisms in most of the cases (65 â 75%), propionibacterium is described to be involved in only 1% of cases. This report describes a case of nephritic sediment in a young female patient with a pacemaker implantation 9 years ago because of a third degree atrioventricular block, in which a battery exchange was necessary 2.5 years ago. This young patient was referred from a nephrologist for renal biopsy because of a nephritic sediment and diffuse complaints including low-grade fever with a suspected underlying autoimmune disease. The laboratory examinations were all negative with the exception of a diminished C3 complement level. Blood cultures were positive for propionibacterium, but the microbiologists were considering it as a contamination. 11 more blood cultures collected thereafter were all positive and a transesophageal ultrasound revealed a small vegetation at 1 of the transvenous electrodes of the pacemaker. Because of a penicillin allergy she was treated with clindamycin, and the blood cultures were negative after a few days. After a full course (7 weeks) of antibiotic treatment the C3 complement level normalized and a series of 10 blood cultures remained negative 10 â 15 days after discontinuation of antibiotic therapy. Discussing all the differential diagnoses of a nephritic sediment combined with hypocomplementemia, positive blood cultures and a vegetation on a pacemaker electrode in the transesophageal ultrasound, the diagnosis of an immune complex glomerulonephritis due to a propionibacterium pacemaker infection needs no confirmation by renal biopsy.

A review of the species of Mesopolobus (Chalcidoidea: Pteromalidae) associated with Ceutorhynchus (Coleoptera: Curculionidae) host-species of European origin.

Four species of Mesopolobus Westwood were reared as parasitoids of Ceutorhynchinae hosts in Europe during surveys in 2000-2004. An illustrated key is given to differentiate the four species, M. gemellus Baur & Muller sp. n., M. incultus (Walker), M. morys (Walker) and M. trasullus (Walker), plus M. moryoides Gibson, a parasitoid of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), in North America. Pteromalus clavicornis Walker is recognized as a junior synonym of M. incultus syn. n., and Pteromalus berecynthos Walker (also a junior synonym of M. incultus) is considered a correct original spelling. For Disema pallipes Förster (a junior synonym of Mesopolobus morys), a lectotype is designated. Mesopolobus morys is for the first time accurately associated with the seed weevil Ceutorhynchus turbatus (Schultze), a potential agent for classical biological control, of hoary cress, Lepidium draba L. (Brassicaceae), in North America. Mesopolobus gemellus is associated with another seed weevil, Ceutorhynchus typhae (=C. floralis) (Herbst), in pods of shepherd's purse, Capsella bursa-pastoris (L.) Medik. (Brassicaceae). Implications of the host-parasitoid associations are discussed relative to the introduction of species to North America for classical biological control of the cabbage seedpod weevil.

Potential for classical biological control of the potato bug Closterotomus norwegicus (Hemiptera: Miridae): description, parasitism and host specificity of Peristenus closterotomae sp. n. (Hymenoptera: Braconidae).

The potato bug, Closterotomus norwegicus (Gmelin) (Hemiptera: Miridae) is an introduced pest of lucerne, white clover and lotus seed crops in New Zealand and a key pest of pistachios in California, USA. Efforts were made to identify potential biological control agents of C. norwegicus in Europe. A total of eight parasitoids, including six primary parasitoids from the genus Peristenus (Hymenoptera: Braconidae) and two hyperparasitoids from the genus Mesochorus (Hymenoptera: Ichneumonidae), were reared from C. norwegicus nymphs collected in various habitats in northern Germany. With a proportion of more than 85% of all C. norwegicus parasitoids, Peristenus closterotomae (Hymenoptera: Braconidae), a new species, was the most dominant parasitoid, whereas other parasitoid species only occurred sporadically. Peristenus closterotomae did not fit in the keys to any described species and is described as new to science. Parasitism caused by P. closterotomae was on average 24% (maximum 77%). To assess the host specificity of parasitoids associated with C. norwegicus, the parasitoid complexes of various Miridae occurring simultaneously with C. norwegicus were studied. Peristenus closterotomae was frequently reared from Calocoris affinis (Herrich-Schaeffer), and a few specimens were reared from Calocoris roseomaculatus (De Geer) and the meadow plant bug, Leptopterna dolobrata (Linnaeus) (all Hemiptera: Miridae). The remaining primary parasitoids associated with C. norwegicus were found to be dominant in hosts other than C. norwegicus. Whether nymphal parasitoids may potentially be used in a classical biological control initiative against the potato bug in countries where it is introduced and considered to be a pest is discussed.

Controlling Lygus plant bugs (Heteroptera: Miridae) with European Peristenus relictus (Hymenoptera: Braconidae) in Canada--risky or not?

The European Peristenus relictus Loan (syn. P. stygicus) has been considered for biological control of Lygus plant bugs native to Canada. Laboratory and field studies were conducted in the area of origin to evaluate the host specificity of P. relictus. Laboratory choice and no-choice tests demonstrated that P. relictus attacked all non-target species offered (fundamental host range). However, closely related non-target mirids (tribe Mirini) were generally well accepted by P. relictus, while hosts from the tribe Stenodemini were less frequently attacked and less suitable for parasitoid development. To validate the laboratory results, a thorough examination of the parasitoid complex of common mirids in Europe was conducted to determine which non-target species may serve as alternative hosts for P. relictus in a natural situation (ecological host range). When comparing both approaches, the fundamental host range of P. relictus matched its ecological host range. In addition to three Lygus species, the ecological host range of P. relictus in the area of Schleswig-Holstein, northern Germany, contains at least 16 non-target species, including hosts belonging to the subfamilies Mirinae, Phylinae and Bryocorinae. A broad ecological and fundamental host range suggests that P. relictus is a generalist; however, P. relictus was not the primary contributor to parasitism of most non-target hosts studied. Although P. relictus is assumed to be of minor importance for regulating non-target populations in the area of investigation, the results of the present study indicate that P. relictus has the potential to use non-target host populations for reproduction.

Screening of entomopathogenic nematodes for virulence against the invasive western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) in Europe.

Entomopathogenic nematode species available in Europe were screened for their efficacy against both the root-feeding larvae and silk-feeding adults of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Laboratory screening tests were aimed at the selection of candidate biological control agents for the management of this invasive alien pest in Europe. Steinernema glaseri, S. arenarium, S. abassi, S. bicornutum, S. feltiae, S. kraussei, S. carpocapsae and Heterorhabditis bacteriophora were studied to determine their virulence against third instar larvae and adults of D. v. virgifera in small-volume arenas (using nematode concentrations of 0.5, 0.8, 7.9 and 15.9 infective juveniles cm-2). All nematode species were able to invade and propagate in D. v. virgifera larvae, but adults were rarely infected. At concentrations of 7.9 and 15.9 cm-2, S. glaseri, S. arenarium, S. abassi and H. bacteriophora caused the highest larval mortality of up to 77%. Steinernema bicornutum, S. abassi, S. carpocapsae and H. bacteriophora appeared to have a high propagation level, producing 5970+/-779, 5595+/-811, 5341+/-1177 and 4039+/-1025 infective juveniles per larva, respectively. Steinernema glaseri, S. arenarium, S. feltiae, S. kraussei and H. bacteriophora were further screened at a concentration of 16.7 nematodes cm-2 against third instar larvae in medium-volume arenas (sand-filled trays with maize plants). Heterorhabditis bacteriophora, S. arenarium and S. feltiae caused the highest larval mortality with 77+/-16.6%, 67+/-3.5%, and 57+/-17.1%, respectively. In a next step, criteria for rating the entomopathogenic nematode species were applied based on results obtained for virulence and propagation, and for current production costs and availability in Europe. These criteria were then rated to determine the potential of the nematodes for further field testing. Results showed the highest potential in H. bacteriophora, followed by S. arenarium and S. feltiae, for further testing as candidate biological control agents.

Basic biology and small-scale rearing of Celatoria compressa(Diptera: Tachinidae), a parasitoid of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae).

The tachinid Celatoria compressa Wulp has been evaluated as a candidate biological control agent for the western corn rootworm, Diabrotica virgifera virgiferaLeConte, in Europe, where it is an invasive alien pest of maize. Special emphasis has been placed on understanding aspects of the parasitoid basic biology and on developing a rearing technique for a small-scale production of C. compressapuparia. The age of C. compressa adults was found to be the most crucial factor in achieving mating. Only newly emerged, 1-h-old females, mated successfully with 2- to 5-day-old males, achieving a success rate of 74%. After mating, a prelarviposition period of 4 days occurred. The 5-day-old C. compressa females inserted their eggs containing fully-developed first instars directly into adults of D. v. virgifera. Total larval and pupal developmental time, including a pre-larviposition period of 4 days, was 29 days under quarantine laboratory conditions (25 degrees C daytime, 15 degrees C at night, L:D 14:10, 50% +/- 10% r.h). Females of C. compressa were capable of producing on average 30 puparia throughout a female's mean larviposition period of 15 days. A large number of host attacks by C. compressa were unsuccessful, resulting in a mean larviposition success rate of 24% per female. Parasitoid females appear to have difficulties inserting the egg through the intersegmental sutures or membranes around leg openings of the host adults. Although the small-scale rearing technique of C. compressa presented is both time and labour intensive, C. compressa has been reared successfully for at least 20 successive generations without shifting the 1 male : 1 female sex ratio using a non-diapause strain of D. v. virgifera.

Continuing CAPD after herniotomy.

There is still controversy as to whether PD-treatment can be safely continued after herniotomy (HT). Many nephrologists withhold PD-treatment for several weeks after HT in fear of dialysate leakage and/or hernia recurrence. We report on 12 patients (2 women, 10 men) in whom HT was performed either for umbilical (n = 6), inguinal (n = 6) or open processus vaginalis (n = 3). Surgery was performed according to the Lichtenstein method with insertion of a Marlex-mesh and ligation of the hernia sac. In all patients PD treatment was paused for the day of surgery and 1 to 3 days postoperatively, depending on RRF. Low volume (1.0 to 1.5 l) and high frequency exchanges (6 exchanges per day) were started for several days with a gradual reinstitution of the former PD-regimen within the next 2 to 4 weeks. All patients did well rapidly with no uraemia-or dialysis-related complications. No leakage and no hernia recurrence could be observed 3 months thereafter. None of the patients had to be haemodialysed intercurrently. In conclusion, continuing a modified regimen of PD-treatment after HT seems to be safe and comfortable for the patient.