Comparison of Resistance to Sliding between Brackets and Archwires Utilizing Various Ligature Materials

Objectives: The purpose of this study was to investigate the association between ligature material and frictional force created during orthodontic cuspid retraction. Maximum static and mean kinetic frictional resistance between conventional metallic orthodontic appliances and esthetic orthodontic appliances will be compared as well. Background: The use of ceramic brackets in conjunction with coated archwires and ligatures as an alternative to conventional stainless steel appliances has increased in response to the demand for more esthetic orthodontic appliances. Esthetic appliances are associated with increased frictional forces and therefore thought to slow the orthodontic treatment. Knowledge of frictional forces generated within various orthodontic appliances is necessary so that appropriate forces can be delivered to achieve clinically desirable rate of tooth movement during sliding mechanics. Frictional forces at the bracket-archwire-ligature interface can affect sliding mechanics. Methods and Materials: In order to measure and compare frictional forces at the bracket-archwire-ligature interface, four maxillary premolar brackets were mounted on a Plexiglass acrylic sheet and one movable bracket was attached to the center of the archwire span. Two types of brackets were used: stainless steel (SS) and ceramic. Brackets used were 0.022 x 0.028 inch slot with RT prescription (DENTSPLY GAC). Tests were performed with 0.017x0.025” SS and 0.017x0.025” Epoxy-coated SS archwires on a Universal Testing Machine (Instron, Grove City, PA) at a crosshead speed of 2.5mm/min, as used by Khamatkar et al2. Archwires were ligated to brackets using 0.010” stainless steel, 0.010” Teflon-coated stainless steel and elastomeric ligatures. The movable bracket was fitted with a 10mm long, 0.045” thick stainless steel arm. A 100gm weight was suspended from the arm to represent the force acting at the center of resistance. Mean kinetic friction was measured for 120 seconds at ten second intervals, beginning at the 30-second time point. Maximum static and kinetic friction measurements were repeated six times and the mean was calculated for each bracket, archwire and ligature combination. Results: Elastomeric ligatures produced more frictional forces than stainless steel ligatures. Teflon-coated coated stainless steel ligatures generated the least amount of frictional resistance. The combination of ceramic bracket, epoxy-coated stainless steel archwire and Teflon-coated stainless steel ligature produced frictional forces that were lower than those by stainless steel bracket, stainless steel archwire and stainless steel ligature. Conclusions: The ligature material used plays a crucial role in the generation of frictional forces at the bracket-archwire interface. Ceramic brackets are comparable to stainless steel brackets in the amount of frictional forces produced. However, the epoxy-coated stainless steel archwires are not as efficient due to the lack of durability of the surface coating

The Quality of Caregiver-Infant Interactions and Neurodevelopmental Outcomes of Infants Prenatally Exposed to Pesticides in Banana Growing Areas in Costa Rica

Background: The quality of early caregiver-child interactions is recognized as one of the strongest influences on children’s cognitive and social development, and among the most significant modifiable environmental factors. Epigenetic studies show that maternal nurturing (i.e., licking and grooming by mothers towards baby rats) promotes positive development in young rats who have experienced prenatal environmental adversity. However, no study to date has examined the impact of caregiving interactions within the context of prenatal environmental exposures. The objective of this dissertation research was to explore the relationship between the quality of caregiver-infant interactions and infant neurodevelopmental outcomes in a high-risk sample of mother-infant dyads living within poverty-stricken and pesticide-exposed banana growing areas in rural Costa Rica. This international, community-based field study was part of a larger, ongoing longitudinal study examining the developmental outcomes of infants prenatally exposed to pesticides: the Infants’ Environmental Health Study. Methods: Home visits were conducted with 94 caregiver-infant dyads living in banana-growing villages in Matina county, Costa Rica. The quality of caregiver-infant interactions was measured using a standardized observational task: the Nursing Child Assessment Satellite Training Teaching scale. One-year infant neurodevelopmental outcomes (i.e., cognitive, language, motor and social-emotional) were assessed using the Bayley-III. Multiple regression analyses examined associations between overall quality of caregiver-infant interactions and Bayley-III outcomes, adjusting for pesticide exposure and confounders. Results: Compared to U.S. Hispanic mothers, 35% of the sample had overall caregiving interaction scores at/below the 10th percentile cutoff, indicating less than optimal interactions. Quality of caregiving interactions was significantly associated with infants’ expressive language abilities (r = 0.072, p<.05). Aspects of caregiving such as stimulation and growth-fostering of infants were identified as key predictors of language outcomes. Conclusions: The results of this study suggest a positive impact of early caregiving on infant neurodevelopment for infants experiencing the double burden of environmental exposure and poverty, and highlight aspects of caregiving that can be modified to help improve outcomes of these children. The results have important implications for environmental health research and for early intervention work with this population and with other populations having environmental and concomitant risks

Students’ perception of the learning environment in a new medical college by means of the DREEM inventory

Background: The educational environment in a college is one of the most important factors in determining the success of the curriculum and the student. The DREEM inventory is a validated global instrument for measuring the educational environment in undergraduate medical education. A study was undertaken to assess the educational environment as perceived by the students of a new medical college established in India in 2008.Objectives: To compare the quality of the educational environment in preclinical years as perceived by the first two batches of students in a new medical college so that appropriate remedial measures could be taken, and also to identify gender differences, if any in the students’ perception.Methods: The DREEM questionnaire was administered to 156 students (2008 batch, n=56 and 2009 batch, n=100) on different occasions after a lecture class. Purpose of the study was explained to the students before administering the questionnaire. Confidentiality was maintained. Statistical analysis used: Cronbachs alpha for internal consistency and reliability. Unpaired t test was used for comparison.Results: The response rate was 100% (256 /256 students). The overall DREEM score was 126.3/200 indicating that perception of the educational environment of the medical school was more positive than negative. However, the study revealed some problem areas within the educational environment.Conclusion: A large number of diverse and hidden factors influence the way students perceive their educational environment. It should be a continuous process to monitor the feedbacks from the students to identify problem areas so that necessary remedial measures can be instituted at the earliest

Virtual assistant in phone conversation

This disclosure describes techniques to provide a virtual assistant in a regular telephone call. The technique provides access to a virtual assistant to phone calls without the calling user device having a data connection. A user interface is provided that enables a user to selectively add a virtual assistant to a telephone call at call initiation or during an ongoing call. Upon user selection, the virtual assistant is added to the call along with the user selected call recipient, thus providing a conference call. With user permission, the virtual assistant accesses call audio and responds to user commands. The techniques are suitable for use by users that do not have access to a data plan or a data connection, e.g., users in remote areas, users of feature phones, etc

Biodiversity Conservation Through Urban Green Spaces: A Case Study of Gujarat University Campus in Ahmedabad

The present study deals with the phytodiversity of Gujarat University campus and the surrounding region which forms an important green space in the urban environment of Ahmedabad city in Gujarat state, India. The extensive field surveys were carried out in the vast study area during 2004 to 2006 covering four different seasons viz. summer, winter, monsoon and spring to cover annual, biennial and perennial plants. A total of 451 species of flowering plants belonging to 338 genera and 101 families were recorded in the study area. Along with these three pteridophytes, two gymnosperms and the algae and fungi group appearing mostly in the monsoon season were also recorded in the study. Among the flowering plants, the herbs were found to be dominant, indicating they favored the climatic factors like less rainfall and high temperature in the study area. Raunkier’s biological life forms revealed the dominance of therophytes and phanerophytes, indicating ‘Thero-Phanerophytic’ phytoclimate in the region. The urban green spaces with such rich plant diversity need to be conserved, especially with the help of the local population, in order to maintain a good environment and biodiversity, thereby improving the overall quality of life

Primary Ovarian Pregnancy - A Rare Case Report

We report the rare case of a 27-year-old female who presented to the emergency department with severe pain in the lower abdomen. She gave a history of a spontaneus pregnancy of 5 weeks gestation with a history of irregular spotting on and off. The total leukocyte count was 25,000/cmm and β-human chorionic gonadotropin level was 984.7 IU/mL. Ultrasound showed an adnexal mass with hemoperitoneum. An ovarian wedge resection was done. She made good postoperative recovery and was discharged on the third postoperative day. Histology confirmed a ruptured ovarian ectopic pregnancy. Ovarian ectopic pregnancy is a rare condition and is associated with the use of assisted reproductive techniques. This case is unusual as it was a spontaneous pregnancy with no history of use of any assisted reproductive techniques

CPT Evaluation of Liquefaction Potential Using Neural Networks

The increasing popularity of the cone penetration test (CPT) for site investigations has led to several methods for predicting liquefaction potential from CPT data. This paper describes a feed-forward neural network model trained by back-propagation for predicting liquefaction potential. The model requires the following seven input variables: cone resistance, total vertical stress, effective vertical stress, earthquake magnitude, maximum horizontal acceleration at ground surface, the mean grain size D50, and the seismic shear-stress ratio. A total of ninety-six data sets from different sites around the world were used for training, and eighty-two data sets were used for testing and validating the neural network model. The model gave an overall success rate of 96% for correctly predicting the liquefaction potential

Unpacking gentrification 2.0: A systems oriented design study uncovering underlying systemic forces in the context of access to housing

This paper explores how despite progressive egalitarian policies, systems can have inherent power dynamics that gravitate towards systemic inequities. By applying systems oriented design (SOD) tools and methodologies to the topic of urban gentrification in Norwegian context, this study done with a systemic lens reveals the invisible power dynamics embedded within the Norwegian housing system which seem to favour one segment of citizens over others. When the urban context (within which such a biased system exists) undergoes gentrification, the negative consequences can be much more damaging than anticipated. This study finds patterns of disparity arise in terms of access and agency between two schematic groups, native Norwegians and immigrants, where inequities are then transferred over generations, with long term impact suggesting a poverty trap across ethnic lines. The paper highlights how systems oriented design and its approaches can be used to uncover the otherwise invisible undercurrents existing within our urban systems. A design response is conceptualised in order to critically reflect on the limitations and challenges of this approach and the evolving role of the designer

From Wealth to Well-being – A systems oriented design exploration of imagining alternatives in urban housing

This paper argues that a Systems Oriented Design (SOD) view has the potential to articulate and materialise community centred notions of care and wellbeing when exploring alternatives in urban housing and alternative futures within complex systems. This is exemplified concerning urban housing in the Norwegian context and by developing and applying a Design-Analysis Framework to articulate the conceptualisation and potential of alternative near-futures of urban dwelling. Presenting this SOD view, a conceptual housing model is visualised and materialised in the form of design artefacts and user-situated scenarios. These are drawn from a completed study centred on stakeholder views and literature reviews on policies and practices on housing while exploring speculative and futures design scenario building for the manifestation of potential alternatives. This paper contributes to SOD by offering a Design-Analysis Framework; it offers an analytical and descriptive account of how this framework helps raise questions about the nature of urban housing, well-being, policy and practices of dwelling, community, and care. Housing and well-being Access to safe, quality, affordable housing – and supports necessary to maintain that housing constitutes one of the most basic and powerful social determinants of health and well-being. (Centre for Supportive Housing, 2014). In the social-democratic society of Norway, home-ownership as a mode of dwelling is promoted as it accounts for one of the primary ways of building welfare. While the asset-based treatment of housing supports this goal, housing trends suggest fewer citizens being able to become homeowners. (Oslo Kommune, 2019) Current systems dynamics mirror the ‘Success to Successful’ archetype which disproportionately affects poorer, immigrant and young members of society, creating disadvantage in the short term and perpetuating vulnerabilities within these communities in the long term. (Sandlie and Gulbrandsen, 2017