Effects of ion irradiation on conductivity of CrSi_2 thin films

Electrical resistivity measurements are used to study damage in CrSi_2 thin films induced by Ne, Ar, or Xe ion irradiation over a fluence range of 10^(10)–10^(15) ions cm^(−2). Irradiation produces a factor of 5–12 increase in film conductivity at the higher fluences. The influence of defect generation and recombination is evident. We speculate that formation of a compound defect is a dominant factor enhancing film conductivity. A temperature dependence at low fluences is reported and tentatively identified

Chemical effects in ion mixing of a ternary system (metal-SiO_2)

The mixing of Ti, Cr, and Ni thin films with SiO_2 by low‐temperature (−196–25 °C) irradiation with 290 keV Xe has been investigated. Comparison of the morphology of the intermixed region and the dose dependences of net metal transport into SiO_2 reveals that long range motion and phase formation probably occur as separate and sequential processes. Kinetic limitations suppress chemical effects in these systems during the initial transport process. Chemical interactions influence the subsequent phase formation

Effect of dose rate on ion beam mixing in Nb-Si

The influence of dose rate, i.e., ion flux, on ion beam mixing in Nb‐Si bilayer samples was measured at room temperature and 325 °C. At the higher temperature, an increase in dose rate of a factor of 20 caused a decrease in the thickness of the mixed layer by a factor of 1.6 for equal total doses. At room temperature, the same change in flux had no effect on mixing. These results are consistent with radiation‐enhanced diffusion theory in the recombination‐limited regime

Correlation between the cohesive energy and the onset of radiation-enhanced diffusion in ion mixing

A correlation between the cohesive energy of elemental solids and the characteristic temperature Tc for the onset of radiation-enhanced diffusion during ion mixing is established. This correlation enables one to predict the onset of radiation-enhanced diffusion for systems which have not yet been investigated. A theoretical argument based on the current models of cascade mixing and radiation-enhanced diffusion is provided as a basis for understanding this observation

Construction management contracts: law and practice

The context of construction management (CM) reveals that this method of procurement is as much a management philosophy as a contract structure. It is important to consider legal and contractual issues in this context. The interplay between management and law is complex and often misunderstood. Before considering specific issues, the use of contractual remedies in business agreements is discussed. In addition, the extent to which standardising a form of contract detracts or contributes to the success of projects is also considered. The dearth of judicial decisions, and the lack of a standard form, render it difficult to be specific about legal issues. Therefore, the main discussion of legal issues is centred around a recently completed research project which involved eliciting the views of a cross-section of experienced construction management clients, consultants and trade contractors. These interviews are used as the basis for highlighting some of the most important legal points to consider when setting up CM projects. The interviews revealed that the advantage of CM is the proximity of the client to the trade contractors and the disadvantage is that it depends on a high degree of professionalism and experience; qualities which are unfortunately difficult to find in the UK construction industry

Regulation of the human p21((waf1/cip1)) gene promoter via multiple binding sites for p53 and the vitamin D(3) receptor

The main regulator of the human tumor suppresser gene p21((waf1/cip1)) is the transcription factor p53, but more recently it has been suggested to be a primary anti-proliferative target for the nuclear receptor VDR in the presence of its ligand 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)). To identify VDR responding regions, we analyzed 20 overlapping regions covering the first 7.1 kb of the p21((waf1/cip1)) promoter in MCF-7 human breast cancer cells using chromatin immuno-precipitation assays (ChIP) with antibodies against p53 and VDR. We confirmed two known p53 binding regions at approximate positions −1400 and −2300 and identified a novel site at position −4500. In addition, we found three VDR-associated promoter regions at positions −2300, −4500 and −6900, i.e. two regions showed binding for both p53 and VDR. In silico screening and in vitro binding assays using recombinant and in vitro translated proteins identified five p53 binding sites within the three p53-positive promoter regions and also five 1α,25(OH)(2)D(3) response elements within the three VDR-positive regions. Reporter gene assays confirmed the expected responsiveness of the respective promoter regions to the p53 inducer 5-fluorouracil and 1α,25(OH)(2)D(3). Moreover, re-ChIP assays confirmed the functionality of the three 1α,25(OH)(2)D(3)-reponsive promoter regions by monitoring simultaneous occupancy of VDR with the co-activator proteins CBP, SRC-1 and TRAP220. Taken together, we demonstrated that the human p21((waf1/cip1)) gene is a primary 1α,25(OH)(2)D(3)-responding gene with at least three VDR binding promoter regions, in two of which also p53 co-localizes

Over-winter persistence of supraglacial lakes on the Greenland Ice Sheet: Results and insights from a new model

AbstractWe present a newly developed 1-D numerical energy-balance and phase transition supraglacial lake model: GlacierLake. GlacierLake incorporates snowfall, in situ snow and ice melt, incoming water from the surrounding catchment, ice lid formation, basal freeze-up and thermal stratification. Snow cover and temperature are varied to test lake development through winter and the maximum lid thickness is recorded. Average wintertime temperatures of −2 to$-30^{\circ }{\rm C}$and total snowfall of 0 to 3.45 m lead to a range of the maximum lid thickness from 1.2 to 2.8 m after${\sim }250$days, with snow cover exerting the dominant control. An initial ice temperature of$-15^{\circ }{\rm C}$with simulated advection of cold ice from upstream results in 0.6 m of basal freeze-up. This suggests that lakes with water depths above 1.3 to 3.4 m (dependent on winter snowfall and temperature) upon lid formation will persist through winter. These buried lakes can provide a sizeable water store at the start of the melt season, expedite future lake formation and warm underlying ice even in winter.NER

Rituximab monitoring and redosing in pediatric neuromyelitis optica spectrum disorder.

Abstract OBJECTIVE: To study rituximab in pediatric neuromyelitis optica (NMO)/NMO spectrum disorders (NMOSD) and the relationship between rituximab, B cell repopulation, and relapses in order to improve rituximab monitoring and redosing. METHODS: Multicenter retrospective study of 16 children with NMO/NMOSD receiving 652 rituximab courses. According to CD19 counts, events during rituximab were categorized as "repopulation," "depletion," or "depletion failure" relapses (repopulation threshold CD19 6510 7 10(6) cells/L). RESULTS: The 16 patients (14 girls; mean age 9.6 years, range 1.8-15.3) had a mean of 6.1 events (range 1-11) during a mean follow-up of 6.1 years (range 1.6-13.6) and received a total of 76 rituximab courses (mean 4.7, range 2-9) in 42.6-year cohort treatment. Before rituximab, 62.5% had received azathioprine, mycophenolate mofetil, or cyclophosphamide. Mean time from rituximab to last documented B cell depletion and first repopulation was 4.5 and 6.8 months, respectively, with large interpatient variability. Earliest repopulations occurred with the lowest doses. Significant reduction between pre- and post-rituximab annualized relapse rate (ARR) was observed (p = 0.003). During rituximab, 6 patients were relapse-free, although 21 relapses occurred in 10 patients, including 13 "repopulation," 3 "depletion," and 4 "depletion failure" relapses. Of the 13 "repopulation" relapses, 4 had CD19 10-50 7 10(6) cells/L, 10 had inadequate monitoring ( 641 CD19 in the 4 months before relapses), and 5 had delayed redosing after repopulation detection. CONCLUSION: Rituximab is effective in relapse prevention, but B cell repopulation creates a risk of relapse. Redosing before B cell repopulation could reduce the relapse risk further. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that rituximab significantly reduces ARR in pediatric NMO/NMOSD. This study also demonstrates a relationship between B cell repopulation and relapses

Painting the ideal home: using art to express visions of technologically supported independent living for older people in North East England

This paper describes the investigation of the development of future technological products to support older people in everyday living through the agency of a community art group. Recent research has identified a number of challenges facing designers seeking to use traditional participatory design approaches to gather technology requirements data from older people. Here, a project is described that sought to get a group of older people to think creatively about their needs and desires for technological support through the medium of paint. The artistic expression technique described in this article allowed the identification of issues that had also been found by previous research that used a range of different techniques. This indicates that the approach shows promise, as it allows information to be gathered in an environment that is comfortable and familiar using methods already known by the participants and which they find enjoyable. It provides a complement (or possible alternative) to standard protocols and has the potential benefit of extracting even richer information as the primary task for participants is enjoyable in its own right and is not associated with an interrogative process. Furthermore, it is argued that some of the key risks of traditional approaches are lessened or removed by the naturalistic setting of this approach

(+)-Hexacyclinol

A sample of the title compound [systematic name: (1aS,2aS,3S,5aS,6aS,7R,7aS,7bS,8R,8aS,10R)-7-hydr­oxy-3-(1-meth­oxy-1-methyl­ethyl)-10-(2-methyl-1-propen­yl)-1a,5a,6a,7,7a,7b,8,8a-octa­hydro-2H-8,2a-(epoxy­methano)phenanthro[2,3-b:6,7-b′]bis­oxirene-2,5(3H)-dione], C23H28O7, was generated by enanti­oselective synthesis. There are three mol­ecules of the compound in the crystallographic asymmetric unit. Hydrogen bonding between alcohol H atoms and keto groups of adjacent mol­ecules appears to stabilize the structure. The compound is enanti­omerically pure but the absolute configuration could not be determined directly in this study. Accordingly, the illustrated configuration was assigned on the basis of the nature of the chiral nonracemic precursor used in the synthesis