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Due to high development demands, environmental impact assessment (EIA) systems internationally are under increasing pressure to simplify, streamline and demonstrate efficiency. South Africa, as a country, has decades of experience in finding solutions to this challenge. Here we aim to provide a critical reflection on the different streamlining interventions implemented over time. Five key interventions are covered, namely: exemptions, refined screening activities, norms and standards, stricter time frames, and the introduction of strategic instruments. We conclude that although well intentioned, attempts at continually refined and expanded legislation, policy, guidelines and protocols have had the opposite effect, by making the system inefficient, overly complex and confusing. Two pragmatic recommendations are made, namely: (i) to provide for more discretion in decision-making, especially during screening, and (ii) to provide for an exit decision after scoping. [ABSTRACT FROM AUTHOR]

We generalize a native Nb 2 O 5 dissolution model [G. Ciovati, Appl. Phys. Lett. 89, 022507 (2006)] to sequential overlayer dissolutions, multilayer dissolution, and realistic temperature profiles, which may be applicable to other materials. The model is applied to secondary ion mass spectrometry depth profile measurements for varying temperature profiles and two-step oxide dissolution in Nb and found to agree well. In the context of the Meissner screening response due to impurity profiles on the length scale of the London penetration depth, the shallow diffusion of O impurities results in a substantial decrease in the peak supercurrent density near the surface. In this framework, oxide dissolution and oxygen diffusion can account for a rise in peak supportable magnetic field in SRF cavities with baking time and a suppression after the optimal baking time is reached, in good agreement with peak-field baking temperatures and times as well as recent quench field measurements. [ABSTRACT FROM AUTHOR]

Purpose: To describe the subjective experience of patients and surgeons during laser in situ keratomileusis (LASIK) using the Intralase 60 kHz or the Visumax 500 kHz femtosecond laser. Setting: Singapore National Eye Centre, Singapore. Design: Prospective randomized clinical study. Methods: In myopic patients, LASIK was performed with the corneal flap created using the 60 kHz laser in 1 eye and the 500 kHz laser in the contralateral eye. Postoperatively, patients completed a standardized validated questionnaire about their subjective intraoperative experiences (eg, light perception, pain, fear). Surgeons reported their intraoperative experiences and preferences. Results: Loss of light perception occurred in 50.0% of 60 kHz laser cases and 0% of 500 kHz laser cases during docking and in 63.0% and 0% of cases, respectively, during laser flap creation (P < .0001). The mean pain score with the 60 kHz laser was significantly higher during docking (P < .0001) but not during laser flap cutting (P = .006). Subconjunctival hemorrhage occurred in 67.4% of eyes with the 60 kHz laser and in 2.2% of eyes with the 500 kHz laser (P < .0001). The 500 kHz laser was preferred by 78.3% of patients, while 21.7% preferred the 60 kHz laser (P < .0001). The surgeons preferred the 60 kHz laser in 50.0% of cases and the 500 kHz laser in 8.7% (P < .0001); 41.3% had no preference. Conclusions: Patients preferred surgery with the 500 kHz laser with no loss of light perception, less pain, less fear, and less subconjunctival hemorrhage. Surgeons preferred the 60 kHz laser. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. [Copyright &y& Elsevier]

Privately protected areas (PPAs) are internationally considered to be important policy implementation instruments to augment and strengthen protected area networks. However, there has been limited reflection on the performance of PPAs over time. This paper aims to identify key risks to the performance of PPAs as policy implementation instruments through the application of Theory of Change (ToC). Identifying and understanding these risks are important to allow for the evaluation and monitoring of PPA performance. The ToC method was applied to a specific PPA policy instrument namely, private nature reserves (PNRs) in the South African context. The research results produced 29 key assumptions translated into 29 key risks. These risk are critically discussed against existing South African and international literature. To test and refine the risks further it is recommended that they be applied to PPA case studies in different contexts. • Theory of change (ToC) is applied to privately protected areas (PPAs). • 29 key assumptions are identified that underpin the performance of PPAs. • Key assumptions are translated into 29 key risks to the performance of PPAs. • These key risks can be used to evaluate the future performance of PPAs. [ABSTRACT FROM AUTHOR]

PURPOSE: To compare the efficacy, predictability, and refractive outcomes of laser in situ kera-tomileusis (LASIK) using 2 femtosecond platforms for flap creation. SETTING: Multisurgeon single center. DESIGN: Clinical trial. METHODS: Bilateral femtosecond LASIK was performed using the Wavelight Allegretto Eye-Q 400 Hz excimer laser system. The Visumax femtosecond platform (Group 1) was used to create the LASIK flap in 1 eye, while the Intralase femtosecond platform (Group 2) was used to create the LASIK flap in the contralateral eye. The preoperative, 1-month, and 3-month postoperative visual acuities, refraction, and contrast sensitivity in the 2 groups were compared. RESULTS: The study enrolled 45 patients. Three months after femtosecond LASIK, 79.5% of eyes in Group 1 and 82.1% in Group 2 achieved an uncorrected distance visual acuity of 20/20 (P=.808). The mean efficacy index was 0.97 in Group 1 and 0.98 in Group 2 at 3 months (P= .735); 89.7% of eyes in Group 1 and 84.6% of eyes in Group 2 were within ± 0.50 diopter of emmetropia at 3 months (P=.498). No eye in either group lost more than 2 lines of corrected distance visual acuity. The mean safety index at 3 months was 1.11 in Group 1 and 1.10 in Group 2 (P=.570). CONCLUSION: The results of LASIK with both femtosecond lasers were similar, and both platforms produced efficacious and predictable LASIK outcomes. [ABSTRACT FROM AUTHOR]

Two calorimeters, with stainless steel and Cu as the thermal path material for high precision and high power versions, respectively, have been designed and commissioned for the 7.5 GHz surface impedance characterization system at Jefferson Lab to provide low temperature control and measurement for CW power up to 22 W on a 5 cm diameter disk sample which is thermally isolated from the radiofrequency (RF) portion of the system. A power compensation method has been developed to measure the RF induced power on the sample. Simulation and experimental results show that with these two calorimeters, the whole thermal range of interest for superconducting radiofrequency materials has been covered. The power measurement error in the interested power range is within 1.2% and 2.7% for the high precision and high power versions, respectively. Temperature distributions on the sample surface for both versions have been simulated and the accuracy of sample temperature measurements have been analyzed. Both versions have the ability to accept bulk superconductors and thin film superconducting samples with a variety of substrate materials such as Al, Al2O3, Cu, MgO, Nb, and Si. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the between-observer (interobserver) and between-instrument (intraobserver) variability in flap thickness measurements after laser in situ keratomileusis (LASIK) using spectral-domain and time-domain anterior segment optical coherence tomography (AS-OCT). Setting: Singapore National Eye Centre. Design: Evaluation of diagnostic test or technology. Methods: Two independent masked observers measured flap thickness 1 month after LASIK using spectral-domain (RTVue) or time-domain (Visante) AS-OCT. The measurements were taken at central (0.0 mm), −1.5 mm, and +1.5 mm locations. Measurements were repeated to assess between-instrument variability. Results: There was no statistically significant difference in mean flap thickness between the 2 observers at −1.5 mm, 0.0 mm, and +1.5 mm on spectral-domain AS-OCT and at −1.5 mm and +1.5 mm on time-domain AS-OCT (P < .01). There was a statistically significant difference between the 2 observers in the central (0.0 mm) values on time-domain AS-OCT (P=.0008). There was stronger interobserver correlation for spectral-domain AS-OCT at −1.5 mm (r = 0.82), 0.0 mm (r = 0.88), and +1.5 mm (r = 0.88) than for time-domain AS-OCT (r = 0.73, r = 0.62, and r = 0.79, respectively). There was no statistically significant difference in between-instrument measurements. There was stronger between-instrument correlation with spectral-domain AS-OCT than with time-domain AS-OCT at all locations. The mean standard deviation (measure of instrument repeatability) for spectral-domain AS-OCT was 4.19 μm. Conclusion: Spectral-domain AS-OCT had closer agreement in between-observer and between-instrument measurements than time-domain AS-OCT and provided more consistent measurements of post-LASIK flap thickness. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. [Copyright &y& Elsevier]

Purpose: To compare pterygium excision conjunctival autograft surgery using Tisseel fibrin glue versus Vicryl sutures. Method: Prospective randomized clinical trial. Fifty patients were randomized into either sutured graft or glued graft groups. Twenty-five received standard conjunctival autograft sutured with Vicryl and 25 received surgery with the autograft placed with Tisseel fibrin glue. Outcome measures include surgical time, patient discomfort, pathology, complications and recurrence rates at 3, 6 and 12 months. Patients were followed up at days 1, 7, 14, 30, 90, 180 and 365. Results: The mean surgical time for the glue group was significantly shorter at 12 min compared with the suture group at 26 min ( P < 0.001). Postoperative pain was significantly less at day 1 ( P < 0.001) and day 2 ( P < 0.05) but was not significantly different following these visits. Complications in the glue group included one patient with an absent graft at week 1 that required revision of the graft. At 3 months there were no recurrences in the glue group and two recurrences in the suture group. The 6- and 12-month recurrence rate was unchanged and not significantly different between the glue and suture groups (both 0/24 and 2/23, respectively). Conclusion: Both glued and sutured conjunctival autografting procedures are safe and effective methods for pterygium surgery. The glued autograft recurrence rate at 12 months was similar to that of sutured grafts. Conjunctival autograft with fibrin glue in pterygium surgery decreased surgical time and resulted in less postoperative pain in the first 48 hours but had a higher complication rate. [ABSTRACT FROM AUTHOR]

Purpose: To identify which organisms cause bacterial keratitis in a local community and to determine how patients with suspected bacterial keratitis should be initially treated.Methods: The results of all corneal scrapes performed in the ophthalmology department of Christchurch Hospital between 1997 and 2001 were reviewed. All samples were collected at the‘bedside’ by a technician from the microbiology department and were processed immediately.Results: Eighty-seven corneal scrapes were performed on 78 patients. There was a positive Gram stain in 43.7% (38/87) of scrapes. There was a positive culture in 58.6% (51/87) of scrapes. The commonest Gram-positive organisms were coagulase negativeStaphylococci(19.4%) andCorynebacteriumspp. (16.1%). The commonest Gram-negative organisms wereMoraxellaspp. (19.4%) andPseudomonas aeruginosa(3.2%). Every Gram-positive organism was sensitive to chloramphenicol and every Gram-negative organism was sensitive to ciprofloxacin. In contrast, 89% of Gram-negative organisms were sensitive to chloramphenicol and 88% of Gram-positive organisms were sensitive to ciprofloxacin.Conclusion: The results are very different to those reported by other centres. Most notably, a much higher incidence of infection byCorynebacteriumspp. andMoraxellaspp. and a lower incidence ofPseudomonas aeruginosawas found.In this centre it appears appropriate to initially treat patients with Gram-positive organisms with chloramphenicol and patients with Gram-negative organisms with ciprofloxacin. Patients with a negative Gram stain should be treated with alternating chloramphenicol and ciprofloxacin while awaiting culture results. [ABSTRACT FROM AUTHOR]

We consider a system where the superposition of two heterogeneous Poisson traffic streams is offered to an integrated network link in synchronous transfer mode, where one stream follows the blocked and- cleared mode ('loss' mode) and the other can wait (finitely) if bandwidth is not available for connection at the time of arrival ('hold' mode). We assume that each stream has different bandwidth requirements per call. A reservation scheme, called anticipated-release policy, is introduced where an arrival is accepted into a waiting room only if the amount of time this customer Is expected to wait is within acceptable limits. For such a loss/hold system, we provide analytical performance models for exponential service time distributions for both streams as well as for the non-exponential service time distribution case for the traffic stream in 'bold" mode. We also present a method on how to model the waiting time distribution of the traffic stream with "hold" mode. From numerical studies, we observe that blocking can be reduced considerably for both services just by introducing a small waiting room for one traffic class compared to 'loss' mode for both traffic classes. Furthermore, this holds true for the case when a maximum tolerable time limit is imposed on the waiting. Finally, our results indicate that this loss/hold scenario with limited waiting room appears to be virtually insensitive to the service time distribution of the 'hold' mode traffic. [ABSTRACT FROM AUTHOR]

Soil flooding causes rapid reductions in transpiration, stomatal conductance and photosynthesis of many woody plants, which can decrease growth and ultimately result in plant death. This study was conducted to determine the role of the root system in the flooding response. Eastern larch (Larix laricina) seedlings were grown in Plexiglas tubes in which water uptake by flooded and unflooded roots was measured independently. Further flooding studies were conducted with eastern larch and white spruce (Picea glauca) in which stems were girdled. Root hydraulic properties were analyzed using pressure-flow relationships. Transpiration rates of partially flooded plants declined more slowly than fully-flooded plants. Water uptake by unflooded roots of partially flooded seedlings increased momentarily with flooding. After 10d, flooding caused little change in root hydraulic conductance, a decrease in root system reflection coefficient, and an increase in osmotic permeability. Stem girdling had little effect on stomatal conductance and transpiration in comparison to flooding effects. The response of plant tops to flooding appears to be xylem-mediated and in proportion to the amount of root system flooded. Root hydraulic conductance appears to be unaffected by flooding except for a possible temporary increase on the first day following flooding treatments. [ABSTRACT FROM AUTHOR]

A radio frequency (RF) surface impedance characterization (SIC) system that uses a novel sapphire-loaded niobium cavity operating at 7.5 GHz has been developed as a tool to measure the RF surface impedance of flat superconducting material samples. The SIC system can presently make direct calorimetric RF surface impedance measurements on the central 0.8 cm2 area of 5 cm diameter disk samples from 2 to 20 K exposed to RF magnetic fields up to 14 mT. To illustrate system utility, we present first measurement results for a bulk niobium sample. [ABSTRACT FROM AUTHOR]

The aim of this letter is to provide an administrative justice perspective on EIA effectiveness. EIA is described as essentially an administrative instrument, reflecting a number of principles that revolve around an assessment process which should reflect administrative justice. This includes lawfulness, procedural fairness and reasonableness. Consciously and explicitly incorporating these principles into EIA decision-making has significant potential to strengthen EIA effectiveness and making it fit for the twenty-first century. [ABSTRACT FROM AUTHOR]

An energetic condensation technique, cathodic arc discharge deposition, is used to grow epitaxial Niobium (Nb) thin films on a-plane sapphire (hexagonal-closed-packed Al2O3) at moderate substrate heating temperature (<400 °C). The epitaxial Nb(110)/Al2O3(1,1,-2,0) thin films reached a maximum residual resistance ratio (RRR) value 214, despite using a reactor-grade Nb cathode source whose RRR was only 30. The measurements suggest that the film's density of impurities and structural defects are lower when compared to Nb films produced by other techniques, such as magnetron sputtering, e-beam evaporation or molecular-beam-epitaxy. At lower substrate temperature, textured polycrystalline Nb thin films were created, and the films might have twin symmetry grains with {110} orientations in-plane. The texture was revealed by x-ray diffraction pole figures. The twin symmetry might be caused by a combination effect of the Nb/Al2O3 three-dimensional epitaxial relationship ('3D-Registry' Claassen's nomenclature) and the 'Volmer-Weber' (Island) growth model. However, pole figures obtained by electron backscattering diffraction (EBSD) found no twin symmetry on the thin films' topmost surface (∼50 nm in depth). The EBSD pole figures showed only one Nb{110} crystal plane orientation. A possible mechanism is suggested to explain the differences between the bulk (XRD) and surface (EBSD) pole figures. [ABSTRACT FROM AUTHOR]

Explains the work of Team Work Intergenerational Project, a joint project of the Foundation for Exceptional Children and the National Council on the Aging Inc. Volunteers (who serve as mentors) and employers who hire disabled people are matched with disabled youth who need jobs.

(S)-ketamine is an NMDA receptor antagonist, but it also binds to and activates mu opioid receptors (MORs) and kappa opioid receptors in vitro. However, the extent to which these receptors contribute to (S)-ketamine's in vivo pharmacology is unknown. We investigated the extent to which (S)-ketamine interacts with opioid receptors in rats by combining in vitro and in vivo pharmacological approaches, in vivo molecular and functional imaging, and behavioral procedures relevant to human abuse liability. We found that the preferential opioid receptor antagonist naltrexone decreased (S)-ketamine self-administration and (S)-ketamine–induced activation of the nucleus accumbens, a key brain reward region. A single reinforcing dose of (S)-ketamine occupied brain MORs in vivo, and repeated doses decreased MOR density and activity and decreased heroin reinforcement without producing changes in NMDA receptor or kappa opioid receptor density. These results suggest that (S)-ketamine's abuse liability in humans is mediated in part by brain MORs. [ABSTRACT FROM AUTHOR]

Significance judgements lie at the heart of EIA and provide the basis and justification for overall decision-making. Although the subjective nature of significance judgements is widely recognized, there has been limited research aimed at gaining a deeper understanding of its implications. This paper builds on the growing tradition of exploring learning from psychology in dealing with challenges in EIA practice, in this case, significance judgements. The aim of this research is therefore, to gain a deeper understanding of the psychology underpinning significance judgements. This is achieved by applying 10 concepts from psychology to the four steps in the 'significance spectrum model', namely: decide thresholds, make predictions, judge acceptability and consider mitigation. The results suggest that significance judgements should (with underpinning concepts from psychology provided in parentheses) aim for a limited number of key thresholds (paradox of choice); design thresholds with future gains in mind (loss aversion), reconsider probability scoring (possibility and certainty effect); avoid judgements based on limited information (What You See Is All There Is, WHYSIATI); utilise statistical prediction over expert opinion (expert fallacy); communicate carefully (priming, framing and cognitive ease); and consider personal attitudes and biases (affect heuristic). [ABSTRACT FROM AUTHOR]

Purpose: 6-O-(2-[18F]Fluoroethyl)-6-O-desmethyl-diprenorphine ([18F]FE-DPN) is regarded as a non-selective opioid receptor radiotracer. Procedure: Here, we report the first characterization of [18F]FE-DPN synthesized from the novel precursor, 6-O-(2-tosyloxyethoxy)-6-O-desmethyl-3-O-trityl-diprenorphine (TE-TDDPN), using a one-pot, two-step nucleophilic radiosynthesis to image opioid receptors in rats and mice using positron emission tomography. Results: We also show that [18F]FE-DPN and [3H]DPN exhibit negligible brain uptake in mu opioid receptor (MOR) knockout mice. Conclusions: Taken together with prior findings, our results suggest that [18F]FE-DPN and [3H]DPN preferentially bind to MOR in rodents in vivo. [ABSTRACT FROM AUTHOR]

Improved energy efficiency and reduced cost are greatly desired for advanced particle accelerators. Progress toward these goals can be made by atomically-smoothing the interior surface of the niobium superconducting radiofrequency (SRF) accelerator cavities at the heart of these machines. Laser polishing offers a green alternative to the present aggressive chemical processes. We found parameters suitable for polishing niobium in all surface conditions that are expected for cavity production. Careful measurement of the resulting surface chemistry revealed a modest thinning of the surface oxide layer, but no contamination. [ABSTRACT FROM AUTHOR]

Recently, Nb superconducting radio frequency cavities vacuum heat treated between 300 and 400 °C for a few hours have exhibited very high quality factors (∼5 × 1010 at 2.0 K). Secondary ion mass spectrometry measurements of O, N, and C show that this enhancement in RF surface conductivity is primarily associated with interstitial O alloying via dissolution and diffusion of the native oxide. We use a theory of oxide decomposition and O diffusion to quantify previously unknown parameters crucial in modeling this process. RF measurements of a vacuum heat-treated Nb superconducting radio frequency cavity confirm the minimized surface resistance (higher Q 0 ) previously expected only from 800 °C diffusive alloying with N. [ABSTRACT FROM AUTHOR]

Epitaxial Nb thin films deposited onto the same crystalline insulating surface can evolve in very different fashions depending on specific deposition conditions, thereby affecting their microstructure, surface morphology and superconducting properties. Here, we examine and compare the microstructure and ensuing surface morphology from two distinct Nb/MgO series each with its own epitaxial registry-namely Nb(001)/MgO(001) and Nb(110)/MgO(001)-leading to distinct surface anisotropy and we closely examine the dynamical scaling of the surface features during growth. We compare our findings with those in other metal/MgO epitaxial systems and for the first time, general scaling formalism is applied to analyze anisotropic surfaces exhibiting biaxial symmetry. Further, Power Spectral Density is applied to the specific problem of thin film growth and surface evolution to qualify the set of deposition conditions leading to smoother surfaces. We find good correlation between the surface morphology and microstructure of the various Nb films with superconducting properties such as their residual resistance ratio and lower critical field. [ABSTRACT FROM AUTHOR]

Welander is correct about the misidentified crystal-directions in the top-view sapphire lattice (Fig. 4 [Zhao et al., J. Appl. Phys. 110, 033523 (2011)]). He is also correct about the misorientation of the pole figures in Fig. 4. In Fig. 1 of this response, we have corrected these errors. Perhaps because of these errors, Welander misconstrued our discussion of the Nb crystal growth as claiming a new 3D registry. That was not our intention. Rather, we wished to highlight the role of energetic condensation that drives low-defect crystal growth by a combination of non-equilibrium sub-plantation that disturbs the substrate lattice and thermal annealing that annihilates defects and promotes large-grain crystal growth. [ABSTRACT FROM AUTHOR]

Superconducting radio frequency niobium cavities are the building blocks of modern accelerators for scientific applications. Lower surface resistance, higher fields, and high operating temperatures advance the reach of the future accelerators for scientific discovery as well as potentially enabling cost-effective industrial solutions. We describe the design and performance of an Nb3Sn coating system that converts the inner surface of niobium cavities to an Nb3Sn film. The niobium surface, heated by radiation from the niobium retort, is exposed to Sn and SnCl2 vapor during the heat cycle, which results in about 2 μm Nb3Sn film on the niobium surface. Film composition and structure as well as radio frequency properties with 1-cell R&D cavities and 5-cell practical accelerator cavities are presented. [ABSTRACT FROM AUTHOR]

Background and purpose: The purpose was to determine the test–retest reliability, practice effects, convergent validity and sensitivity to multiple sclerosis (MS) disability of neuroperformance subtests from the patient self‐administered Multiple Sclerosis Performance Test (MSPT) designed to assess low contrast vision (Contrast Sensitivity Test, CST), upper extremity motor function (Manual Dexterity Test, MDT) and lower extremity motor function (Walking Speed Test, WST) and to introduce the concept of regression‐based norms to aid clinical interpretation of performance scores using the MSPT cognition test (Processing Speed Test, PST) as an example. Methods: Substudy 1 assessed test–retest reliability, practice effects and convergent validity of the CST, MDT and WST in 30 MS patients and 30 healthy controls. Substudy 2 examined sensitivity to MS disability in over 600 MS patients as part of their routine clinic assessment. Substudy 3 compared performance on the PST in research volunteers and clinical samples. Results: The CST, MDT and WST were shown to be reliable, valid and sensitive to MS outcomes. Performance was comparable to technician‐administered testing. PST performance was poorer in the clinical sample compared with the research volunteer sample. Conclusions: The self‐administered MSPT neuroperformance modules produce reliable, objective metrics that can be used in clinical practice and support outcomes research. Published studies which require patient voluntary consent may underestimate the rate of cognitive dysfunction observed in a clinical setting. [ABSTRACT FROM AUTHOR]

We report microstructure analyses and superconducting radiofrequency (SRF) measurements of macroscopic scale epitaxial MgB2 films. MgB2 films on 5 cm diameter sapphire disks were fabricated by a hybrid physical chemical vapor deposition (HPCVD) technique. The electron-beam backscattering diffraction (EBSD) results suggest that the film is a single crystal complying with a MgB2(0001) &par; Al2O3(0001) epitaxial relationship. The SRF properties of different film thicknesses (200 and 350 nm) were evaluated under different temperatures and applied fields at 7.4 GHz. A surface resistance of 9 ± 2 &mgr;Ω has been observed at 2.2 K. [ABSTRACT FROM AUTHOR]

Superconducting ultrathin films grown epitaxially ontocrystalline substrates exhibit strained epitaxial growth due to latticemismatch, which can have a significant effect on their superconductingproperties. We present a complete correlation of the surface morphology,crystal growth, strain, microstructure, and superconducting propertiesin single-crystal Nb(110) thin films sputter deposited on a-plane sapphire substrates. Notably, we observe that thelattice mismatch between Nb and sapphire induces the formation ofa hexagonal surface structure during the first three atomic layers.This is followed by a strained bccNb(110) phasewhose in-plane lattice parameter progressively relaxes to bulk value.Similar lattice relaxation was also observed in the direction perpendicularto the interface using X-ray diffraction (XRD) and transmission electronmicroscopy (TEM). Significant perpendicular strain in films up to30 nm thick was found to ultimately affect the superconducting propertiesof the Nb thin films as demonstrated with AC susceptibility measurements,where dissipative effects in the lattice associated with the presenceof strain and associated defects were identified. [ABSTRACT FROM AUTHOR]

Examines silicone [poly(dimethylsiloxane)s PDMS] hydrolysis over a wide range of soil moisture levels. Information on the widespread use of silicone polymers [poly(dimethylsiloxane)s PDMS] and its entry into soils through the disposal of sewage sludge. Details on the fate of this polymer in a variety of soil environments; What are silicone polymers.

Most strains of Helicobacter pylori from patients with peptic ulcer disease or intestinal-type gastric cancer carry cagA, a gene that encodes an immunodominant protein of unknown function, whereas many of the strains from asymptomatically infected persons lack this gene. Recent studies showed that the cagA gene lies near the right end of a approx. 37 kb DNA segment (a pathogenicity island, or PAI) that is unique to cagA[sup +] strains and that the cag PAI was split in half by a transposable element insertion in the reference strain NCTC11638. In complementary experiments reported here, we also found the same cag PAI, and sequenced a 39 kb cosmid clone containing the left ‘cagII’ half of this PAI. Encoded in cagII were four proteins each with homology to four components of multiprotein complexes of Bordetella pertussis (‘Ptl’), Agrobacterium tumefaciens (‘Vir’), and conjugative plasmids (‘Tra’) that help deliver pertussis toxin and T (tumour inducing) and plasmid DNA, respectively, to target eukaryotic or prokaryotic cells, and also homologues of eukaryotic proteins that are involved in cytoskeletal structure. To the left of cagII in this cosmid were genes for homologues of HslU (heat-shock protein) and Era (essential GTPase); to the right of cagII were homologues of genes for a type I restriction endonuclease and ion transport functions. Deletion of the cag PAI had no effect on synthesis of the vacuolating cytotoxin, but this deletion and several cag insertion mutations blocked induction of synthesis of proinflammatory cytokine IL-8 in gastric epithelial cells. Comparisons among H. pylori strains indicated that cag PAI gene content and arrangement are rather well conserved. We also identified two genome rearrangements with end-points in the cag PAI. One, in reference strain NCTC11638, involved IS605, a recently described transposable element (as also found by others). Another rearrangement, in 3 of 10... [ABSTRACT FROM AUTHOR]