292 research outputs found
Memorandum to Chief Designing Engineer, Subject: Hydraulic Model Experimnets for the Design of the Hyrum Spillway
A comparison of walk-in counselling and the wait list model for delivering counselling services
Background: Walk-in counselling has been used to reduce wait times but there are few controlled studies to compare outcomes between walk-in and the traditional model of service delivery.
Aims: To compare change in psychological distress by clients receiving services from two models of service delivery, a walk-in counselling model and a traditional counselling model involving a wait list
Method: Mixed methods sequential explanatory design including quantitative comparison of groups with one pre-test and two follow ups, and qualitative analysis of interviews with a subsample. 524 participants 16 years and older were recruited from two Family Counselling Agencies; the General Health Questionnaire assessed change in psychological distress; prior use of other mental health and instrumental services was also reported.
Results: Hierarchical linear modelling revealed clients of the walk-in model improved faster and were less distressed at the 4-week follow-up compared to the traditional service delivery model. At the 10-week follow-up, both groups had improved and were similar. Participants receiving instrumental services prior to baseline improved more slowly. Qualitative interviews confirmed participants valued the accessibility of the walk-in model.
Conclusions: This study improves methodologically on previous studies of walk-in counselling, an approach to service delivery that is not conducive to randomized controlled trials
An ORMOSIL-containing orthodontic acrylic resin with concomitant improvements in antimicrobial and fracture toughness properties
Global increase in patients seeking orthodontic treatment creates a demand for the use of acrylic resins in removable appliances and retainers. Orthodontic removable appliance wearers have a higher risk of oral infections that are caused by the formation of bacterial and fungal biofilms on the appliance surface. Here, we present the synthetic route for an antibacterial and antifungal organically-modified silicate (ORMOSIL) that has multiple methacryloloxy functionalities attached to a siloxane backbone (quaternary ammonium methacryloxy silicate, or QAMS). By dissolving the water-insoluble, rubbery ORMOSIL in methyl methacrylate, QAMS may be copolymerized with polymethyl methacrylate, and covalently incorporated in the pressure-processed acrylic resin. The latter demonstrated a predominantly contact-killing effect on Streptococcus mutans ATCC 36558 and Actinomyces naselundii ATCC 12104 biofilms, while inhibiting adhesion of Candida albicans ATCC 90028 on the acrylic surface. Apart from its favorable antimicrobial activities, QAMS-containing acrylic resins exhibited decreased water wettability and improved toughness, without adversely affecting the flexural strength and modulus, water sorption and solubility, when compared with QAMS-free acrylic resin. The covalently bound, antimicrobial orthodontic acrylic resin with improved toughness represents advancement over other experimental antimicrobial acrylic resin formulations, in its potential to simultaneously prevent oral infections during appliance wear, and improve the fracture resistance of those appliances.published_or_final_versio
A comparative evaluation of the efficacy of manual, magnetostrictive and piezoelectric ultrasonic instruments: an in vitro profilometric and SEM study
OBJECTIVES: The debridement of diseased root surface is usually performed by mechanical scaling and root planing using manual and power driven instruments. Many new designs in ultrasonic powered scaling tips have been developed. However, their effectiveness as compared to manual curettes has always been debatable. Thus, the objective of this in vitro study was to comparatively evaluate the efficacy of manual, magnetostrictive and piezoelectric ultrasonic instrumentation on periodontally involved extracted teeth using profilometer and scanning electron microscope (SEM). MATERIAL AND METHODS: 30 periodontally involved extracted human teeth were divided into 3 groups. The teeth were instrumented with hand and ultrasonic instruments resembling clinical application. In Group A all teeth were scaled with a new universal hand curette (Hu Friedy Gracey After Five Vision curette; Hu Friedy, Chicago, USA). In Group B Cavitron(TM) FSI - SLI(TM) ultrasonic device with focused spray slimline inserts (Dentsply International Inc., York, PA, USA) were used. In Group C teeth were scaled with an EMS piezoelectric ultrasonic device with prototype modified PS inserts. The surfaces were analyzed by a Precision profilometer to measure the surface roughness (Ra value in µm) consecutively before and after the instrumentation. The samples were examined under SEM at magnifications ranging from 17x to 300x and 600x. RESULTS: The mean Ra values (µm) before and after instrumentation in all the three groups A, B and C were tabulated. After statistically analyzing the data, no significant difference was observed in the three experimental groups. Though there was a decrease in the percentage reduction of Ra values consecutively from group A to C. CONCLUSION: Within the limits of the present study, given that the manual, magnetostrictive and piezoelectric ultrasonic instruments produce the same surface roughness, it can be concluded that their efficacy for creating a biologically compatible surface of periodontally diseased teeth is similar
Extensive degeneracy, Coulomb phase and magnetic monopoles in an artificial realization of the square ice model
Artificial spin ice systems have been introduced as a possible mean to
investigate frustration effects in a well-controlled manner by fabricating
lithographically-patterned two-dimensional arrangements of interacting magnetic
nanostructures. This approach offers the opportunity to visualize
unconventional states of matter, directly in real space, and triggered a wealth
of studies at the frontier between nanomagnetism, statistical thermodynamics
and condensed matter physics. Despite the strong efforts made these last ten
years to provide an artificial realization of the celebrated square ice model,
no simple geometry based on arrays of nanomagnets succeeded to capture the
macroscopically degenerate ground state manifold of the corresponding model.
Instead, in all works reported so far, square lattices of nanomagnets are
characterized by a magnetically ordered ground state consisting of local
flux-closure configurations with alternating chirality. Here, we show
experimentally and theoretically, that all the characteristics of the square
ice model can be observed if the artificial square lattice is properly
designed. The spin configurations we image after demagnetizing our arrays
reveal unambiguous signatures of an algebraic spin liquid state characterized
by the presence of pinch points in the associated magnetic structure factor.
Local excitations, i.e. classical analogues of magnetic monopoles, are found to
be free to evolve in a massively degenerated, divergence-free vacuum. We thus
provide the first lab-on-chip platform allowing the investigation of collective
phenomena, including Coulomb phases and ice-like physics.Comment: 26 pages, 10 figure
Military Training Mission in Iraq: An Exploratory Case Study Research
The purpose of this paper is to investigate how military training is being
conducted by NATO coalition forces in Iraq. Thus, the intent of this paper is to discuss
the implications of existing misalignments between the military forces that are
providing the training and those receiving it. To that end, we have used an exploratory
case study research, which included multiple sources of data collection for corroboration
and triangulation purposes. The results that emerged from the content analysis
showed two types of outcomes that may be relevant to improve the military training
in Iraq. The first outcome is identified as the intangible actions, which were mainly
focused on social relations, with the intent of narrowing the cultural gap between
the international coalition and Iraqi forces. Without surprising, a second outcome is
identified as tangible actions, which were associated with training programs and the
establishment of tactics, techniques, and procedures (TTPs) relevant to small and
medium military units. Future research should focus on programs of “training the
trainers” in order to develop long-term teaching and move forward with sustainable
Iraqi Security Forces (ISF).info:eu-repo/semantics/publishedVersio
Topology by Design in Magnetic nano-Materials: Artificial Spin Ice
Artificial Spin Ices are two dimensional arrays of magnetic, interacting
nano-structures whose geometry can be chosen at will, and whose elementary
degrees of freedom can be characterized directly. They were introduced at first
to study frustration in a controllable setting, to mimic the behavior of spin
ice rare earth pyrochlores, but at more useful temperature and field ranges and
with direct characterization, and to provide practical implementation to
celebrated, exactly solvable models of statistical mechanics previously devised
to gain an understanding of degenerate ensembles with residual entropy. With
the evolution of nano--fabrication and of experimental protocols it is now
possible to characterize the material in real-time, real-space, and to realize
virtually any geometry, for direct control over the collective dynamics. This
has recently opened a path toward the deliberate design of novel, exotic
states, not found in natural materials, and often characterized by topological
properties. Without any pretense of exhaustiveness, we will provide an
introduction to the material, the early works, and then, by reporting on more
recent results, we will proceed to describe the new direction, which includes
the design of desired topological states and their implications to kinetics.Comment: 29 pages, 13 figures, 116 references, Book Chapte
Bacterial morphotype grading for periodontal disease assessment
BACKGROUND: Listgarten and Hellden (1978) used darkfield microscopy of wet mounts to differentiate between healthy and
periodontally diseased sites in the mouth by expressing the different bacterial morphotypes observed as a percentage of the total
number of bacteria counted. This method of periodontal disease assessment gained favour as a diagnostic tool but presented with
the limitation of immediate examination to determine the number of motile rods present and an inability to distinguish between
gingivitis and periodontitis. Grading of bacterial morphotypes into several distinct categories of health or disease (Ison and Hay,
2002), simplified the scoring system of Gram-stained smears for the diagnosis of bacterial vaginosis (Nugent et al. 1991). The
application of a similar grading system using stained smears rather than wet mounts could be advantageous to the diagnosis of
periodontal disease.
OBJECTIVES/AIMS: This study tested the hypothesis that stained smears of dental plaque collected from the gingival crevice of
individuals with varying probing pocket depths (PD) may provide a grading system for periodontal disease assessment.
MATERIALS AND METHODS: Subgingival plaque samples were collected from 49 patients, stained with a silver stain and the
proportions of each bacterial morphotype graded relative to their respective PD measurements.
RESULTS: This technique allowed for a grading system of I–IV, with grade I indicating health and grade IV indicating severe
periodontal disease.
DISCUSSION: Stained smear examination eliminates the time restriction for motile rod enumeration and allows for storage of
smears for future reference.
CONCLUSION: Standardization of the microscopic areas to be evaluated or examined will facilitate the agreement of cut-off values
for the diagnosis of periodontal disease.This material is based on work partially supported financially by the National Research Foundation (NRF) of South Africa
The Effect of Locally Delivered Controlledâ Release Doxycycline or Scaling and Root Planing on Periodontal Maintenance Patients Over 9 Months
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142157/1/jper0022.pd
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