Analysis of fetal heart rate asymmetry before and after 35 weeks of gestation

In this study, we have investigated the evidence of fetal heart rate asymmetry and how the fetal heart rate asymmetry changes before and after 35 weeks of gestation. Noninvasive fetal electrocardiogram (fECG) signals from 45 pregnant women at the gestational age from16 to 41 weeks with normal single pregnancies were analysed. A nonlinear parameter called heart rate asymmetry (HRA) index that measures time asymmetry of RR interval time-series signal was used to understand the changes of HRA in early and late fetus groups. Results indicate that fetal HRA measured by Porta's Index (PI) consistently increases after 35 weeks gestation compared to foetus before 32 weeks of gestation. It might be due to significant changes of sympatho-vagal balance towards delivery with more sympathetic surge. On the other hand, Guzik's Index (GI) showed a mixed effect i.e., increases at lower lags and decreases at higher lags. Finally, fHRA could potentially help identify normal and the pathological autonomic nervous system development.

Proteins, Pathogens, and Failure at the Composite-Tooth Interface

In the United States, composites accounted for nearly 70% of the 173.2 million composite and amalgam restorations placed in 2006 (Kingman et al., 2012), and it is likely that the use of composite will continue to increase as dentists phase out dental amalgam. This trend is not, however, without consequences. The failure rate of composite restorations is double that of amalgam (Ferracane, 2013). Composite restorations accumulate more biofilm, experience more secondary decay, and require more frequent replacement. In vivo biodegradation of the adhesive bond at the composite-tooth interface is a major contributor to the cascade of events leading to restoration failure. Binding by proteins, particularly gp340, from the salivary pellicle leads to biofilm attachment, which accelerates degradation of the interfacial bond and demineralization of the tooth by recruiting the pioneer bacterium Streptococcus mutans to the surface. Bacterial production of lactic acid lowers the pH of the oral microenvironment, erodes hydroxyapatite in enamel and dentin, and promotes hydrolysis of the adhesive. Secreted esterases further hydrolyze the adhesive polymer, exposing the soft underlying collagenous dentinal matrix and allowing further infiltration by the pathogenic biofilm. Manifold approaches are being pursued to increase the longevity of composite dental restorations based on the major contributing factors responsible for degradation. The key material and biological components and the interactions involved in the destructive processes, including recent advances in understanding the structural and molecular basis of biofilm recruitment, are described in this review. Innovative strategies to mitigate these pathogenic effects and slow deterioration are discussed.

General results for the Kumaraswamy-G distribution

For any continuous baseline G distribution [G. M. Cordeiro and M. de Castro, A new family of generalized distributions, J. Statist. Comput. Simul. 81 (2011), pp. 883-898], proposed a new generalized distribution (denoted here with the prefix 'Kw-G'(Kumaraswamy-G)) with two extra positive parameters. They studied some of its mathematical properties and presented special sub-models. We derive a simple representation for the Kw-Gdensity function as a linear combination of exponentiated-G distributions. Some new distributions are proposed as sub-models of this family, for example, the Kw-Chen [Z.A. Chen, A new two-parameter lifetime distribution with bathtub shape or increasing failure rate function, Statist. Probab. Lett. 49 (2000), pp. 155-161], Kw-XTG [M. Xie, Y. Tang, and T.N. Goh, A modified Weibull extension with bathtub failure rate function, Reliab. Eng. System Safety 76 (2002), pp. 279-285] and Kw-Flexible Weibull [M. Bebbington, C. D. Lai, and R. Zitikis, A flexible Weibull extension, Reliab. Eng. System Safety 92 (2007), pp. 719-726]. New properties of the Kw-G distribution are derived which include asymptotes, shapes, moments, moment generating function, mean deviations, Bonferroni and Lorenz curves, reliability, Renyi entropy and Shannon entropy. New properties of the order statistics are investigated. We discuss the estimation of the parameters by maximum likelihood. We provide two applications to real data sets and discuss a bivariate extension of the Kw-G distribution.

New Results Concerning Probability Distributions with Increasing Generalized Failure Rates

The generalized failure rate of a continuous random variable has demonstrable importance in operations management. If the valuation distribution of a product has an increasing generalized failure rate (that is, the distribution is IGFR), then the associated revenue function is unimodal, and when the generalized failure rate is strictly increasing, the global maximum is uniquely specified. The assumption that the distribution is IGFR is thus useful and frequently held in recent pricing, revenue, and supply chain management literature. This note contributes to the IGFR literature in several ways. First, it investigates the prevalence of the IGFR property for the left and right truncations of valuation distributions. Second, we extend the IGFR notion to discrete distributions and contrast it with the continuous distribution case. The note also addresses two errors in the previous IGFR literature. Finally, for future reference, we analyze all common (continuous and discrete) distributions for the prevalence of the IGFR property, and derive and tabulate their generalized failure rates.

Survival and failure rates of orthodontic temporary anchorage devices: a systematic review

AIM: The purpose of this study was to systematically review the literature on the survival rates of palatal implants, Onplants((R)), miniplates and mini screws. MATERIAL AND METHODS: An electronic MEDLINE search supplemented by manual searching was conducted to identify randomized clinical trials, prospective and retrospective cohort studies on palatal implants, Onplants((R)), miniplates and miniscrews with a mean follow-up time of at least 12 weeks and of at least 10 units per modality having been examined clinically at a follow-up visit. Assessment of studies and data abstraction was performed independently by two reviewers. Reported failures of used devices were analyzed using random-effects Poisson regression models to obtain summary estimates and 95% confidence intervals (CI) of failure and survival proportions. RESULTS: The search up to January 2009 provided 390 titles and 71 abstracts with full-text analysis of 34 articles, yielding 27 studies that met the inclusion criteria. In meta-analysis, the failure rate for Onplants((R)) was 17.2% (95% CI: 5.9-35.8%), 10.5% for palatal implants (95% CI: 6.1-18.1%), 16.4% for miniscrews (95% CI: 13.4-20.1%) and 7.3% for miniplates (95% CI: 5.4-9.9%). Miniplates and palatal implants, representing torque-resisting temporary anchorage devices (TADs), when grouped together, showed a 1.92-fold (95% CI: 1.06-2.78) lower clinical failure rate than miniscrews. CONCLUSION: Based on the available evidence in the literature, palatal implants and miniplates showed comparable survival rates of >or=90% over a period of at least 12 weeks, and yielded superior survival than miniscrews. Palatal implants and miniplates for temporary anchorage provide reliable absolute orthodontic anchorage. If the intended orthodontic treatment would require multiple miniscrew placement to provide adequate anchorage, the reliability of such systems is questionable. For patients who are undergoing extensive orthodontic treatment, force vectors may need to be varied or the roots of the teeth to be moved may need to slide past the anchors. In this context, palatal implants or miniplates should be the TADs of choice.

Complication and failure rates with implant-supported fixed dental prostheses and single crowns: a 10-year retrospective study

PURPOSE Clinical studies related to the long-term outcomes with implant-supported reconstructions are still sparse. The aim of this 10-year retrospective study was to assess the rate of mechanical/technical complications and failures with implant supported fixed dental prostheses (FDPs) and single crowns (SCs) in a large cohort of partially edentulous patients. MATERIALS AND METHODS The comprehensive multidisciplinary examination consisted of a medical/dental history, clinical examination, and a radiographic analysis. Prosthodontic examination evaluated the implant-supported reconstructions for mechanical/technical complications and failures, occlusal analysis, presence/absence of attrition, and location, extension, and retention type. RESULTS Out of three hundred ninety seven fixed reconstructions in three hundred three patients, two hundred sixty eight were SCs and one hundred twenty seven were FDPs. Of these three hundred ninety seven implant-supported reconstructions, 18 had failed, yielding a failure rate of 4.5% and a survival rate of 95.5% after a mean observation period of 10.75 years (range: 8.4-13.5 years). The most frequent complication was ceramic chipping (20.31%) followed by occlusal screw loosening (2.57%) and loss of retention (2.06%). No occlusal screw fracture, one abutment loosening, and two abutment fractures were noted. This resulted in a total mechanical/technical complication rate of 24.7%. The prosthetic success rate over a mean follow-up time of 10.75 years was 70.8%. Generalized attrition and FDPs were associated with statistically significantly higher rates of ceramic fractures when compared with SCs. Cantilever extensions, screw retention, anterior versus posterior, and gender did not influence the chipping rate. CONCLUSIONS After a mean exposure time of 10.75 years, high survival rates for reconstructions supported by Sand-blasted Large-grit Acid-etched implants can be expected. Ceramic chipping was the most frequent complication and was increased in dentitions with attrition and in FDPs compared with SCs.

Long-term follow-up of maxillary fixed retention: survival rate and periodontal health.

AIM To assess the long-term success of maxillary fixed retainers, investigate their effect on gingival health, and analyse the survival rate after a mean period of 7 years (minimum 5 years) in retention. SUBJECTS AND METHODS Forty one subjects were included in the study A clinical examination of the upper canine to canine region including gingival index (GI), plaque index, probing depth, and bleeding on probing (BOP) was performed. Intraoral photographs and dental impressions were taken and irregularity index was determined and compared to the values of the immediate post-therapeutic values; failures of retainers were also recorded and analysed. RESULTS The mean observed retention time was 7 years and 5 months. Irregularity index: Changes occurring during retention were statistically different between the lateral incisors bonded to retainers and the canines not bonded to retainers. Only six patients showed changes in irregularity index of the lateral incisors in spite of a retainer in place. Periodontal health: The median value of the GI for all teeth bonded to upper retainers was 1.10 and the median value of the plaque index (PI) was 1.14. PI was not a significant predictor of GI. The overall BOP of the bonded teeth to the retainer for each participant was 22.3 per cent. Failure rate: Twenty-eight out of 41 patients experienced no failure of the upper bonded retainer (68.3 per cent). Detachments were the most frequent incidents. CONCLUSION Although plaque accumulation might be increased in patients with already poor oral hygiene, maxillary bonded retainers caused no significant negative effects on the periodontal health.

Failure mechanism of the all-polyethylene glenoid implant

Fixation failure of glenoid components is the main cause of unsuccessful total shoulder arthroplasties. The characteristics of these failures are still not well understood, hence, attempts at improving the implant fixation are somewhat blind and the failure rate remains high. This lack of understanding is largely due to the fundamental problem that direct observations of failure are impossible as the fixation is inherently embedded within the bone. Twenty custom made implants, reflecting various common fixation designs, and a specimen set-up was prepared to enable direct observation of failure when the specimens were exposed to cyclic superior loads during laboratory experiments. Finite element analyses of the laboratory tests were also carried out to explain the observed failure scenarios. All implants, irrespective of the particular fixation design, failed at the implant-cement interface and failure initiated at the inferior part of the component fixation. Finite element analyses indicated that this failure scenario was caused by a weak and brittle implant-cement interface and tensile stresses in the inferior region possibly worsened by a stress raiser effect at the inferior rim. The results of this study indicate that glenoid failure can be delayed or prevented by improving the implant/cement interface strength. Also any design features that reduce the geometrical stress raiser and the inferior tensile stresses in general should delay implant loosening.

Engaging students in programming

Poor student engagement and high failure rates in first year units were addressed at the Queensland University of Technology (QUT) with a course restructure involving a fresh approach to introducing programming. Students’ first taste of programming in the new course focused less on the language and syntax, and more on problem solving and design, and the role of programming in relation to other technologies they are likely to encounter in their studies. In effect, several technologies that have historically been compartmentalised and taught in isolation have been brought together as a breadth-first introduction to IT. Incorporating databases and Web development technologies into what used to be a purely programming unit gave students a very short introduction to each technology, with programming acting as the glue between each of them. As a result, students not only had a clearer understanding of the application of programming in the real world, but were able to determine their preference or otherwise for each of the technologies introduced, which will help them when the time comes for choosing a course major. Students engaged well in an intensely collaborative learning environment for this unit which was designed to both support the needs of students and meet industry expectations. Attrition from the unit was low, with computer laboratory practical attendance rates for the first time remaining high throughout semester, and the failure rate falling to a single figure percentage.

Identifying critical success factors of ERP Systems at the higher education sector

In response to a range of contextual drivers, the worldwide adoption of ERP Systems in Higher Education Institutions (HEIs) has increased substantially over the past decade. Though the difficulties and high failure rate in implementing ERP systems at university environments have been cited in the literature, research on critical success factors (CSFs) for ERP implementations in this context is rare and fragmented. This paper is part of a larger research effort that aims to contribute to understanding the phenomenon of ERP implementations and evaluations in HEIs in the Australasian region; it identifies, previously reported, critical success factors (CSFs) in relation to ERP system implementations and discusses the importance of these factors.

Meniscal repair in the elite athlete : results of 45 repairs with a minimum 5-year follow-up

Background The preservation of meniscal tissue is important to protect joint surfaces. Purpose We have an aggressive approach to meniscal repair, including repairing tears other than those classically suited to repair. Here we present the medium- to long-term outcome of meniscal repair (inside-out) in elite athletes. Study Design Case series; Level of evidence, 4. Methods Forty-two elite athletes underwent 45 meniscal repairs. All repairs were performed using an arthroscopically assisted inside-out technique. Eighty-three percent of these athletes had ACL reconstruction at the same time. Patients returned a completed questionnaire (including Lysholm and International Knee Documentation Committee [IKDC] scores). Mean follow-up was 8.5 years. Failure was defined by patients developing symptoms of joint line pain and/or locking or swelling requiring repeat arthroscopy and partial meniscectomy. Results The average Lysholm and subjective IKDC scores were 89.6 and 85.4, respectively. Eighty-one percent of patients returned to their main sport and most to a similar level at a mean time of 10.4 months after repair, reflecting the high level of ACL reconstruction in this group. We identified 11 definite failures, 10 medial and 1 lateral meniscus, that required excision; this represents a 24% failure rate. We identified 1 further patient who had possible failed repairs, giving a worst-case failure rate of 26.7% at a mean of 42 months after surgery. However, 7 of these failures were associated with a further injury. Therefore, the atraumatic failure rate was 11%. Age and size and location of the tears were not associated with a higher failure rate. Medial meniscal repairs were significantly more likely to fail than lateral meniscal repairs, with a failure rate of 36.4% and 5.6%, respectively (P < .05). Conclusion Meniscal repair and healing are possible, and most elite athletes can return to their preinjury level of activity.

Peer assisted study sessions

My journey with Peer Assisted Study Sessions, or Supplemental Instruction (SI), began in 1993 when I took over a 1st year, 1st semester unit in QUT's Bachelor of Engineering program. The unit had 500 enrolments with students from all 10 engineering majors at QUT. The 500 students received a 2 hour lecture and a 1 hour tutorial per week, usually run by academic staff or postgraduate students. The unit covered basic mechanics, which comprises a challenging set of topics on how forces interact with various bodies. One normally expects 1st year students to find it difficult to come to grips with the material. However, when I ran that unit in 1993, the failure rate had been usually around 50%.

Reliability analysis and economic equipment replacement appraisal for substation and sub-transmission systems with explicit inclusion of non-repairable failures

The modern society has come to expect the electrical energy on demand, while many of the facilities in power systems are aging beyond repair and maintenance. The risk of failure is increasing with the aging equipments and can pose serious consequences for continuity of electricity supply. As the equipments used in high voltage power networks are very expensive, economically it may not be feasible to purchase and store spares in a warehouse for extended periods of time. On the other hand, there is normally a significant time before receiving equipment once it is ordered. This situation has created a considerable interest in the evaluation and application of probability methods for aging plant and provisions of spares in bulk supply networks, and can be of particular importance for substations. Quantitative adequacy assessment of substation and sub-transmission power systems is generally done using a contingency enumeration approach which includes the evaluation of contingencies, classification of the contingencies based on selected failure criteria. The problem is very complex because of the need to include detailed modelling and operation of substation and sub-transmission equipment using network flow evaluation and to consider multiple levels of component failures. In this thesis a new model associated with aging equipment is developed to combine the standard tools of random failures, as well as specific model for aging failures. This technique is applied in this thesis to include and examine the impact of aging equipments on system reliability of bulk supply loads and consumers in distribution network for defined range of planning years. The power system risk indices depend on many factors such as the actual physical network configuration and operation, aging conditions of the equipment, and the relevant constraints. The impact and importance of equipment reliability on power system risk indices in a network with aging facilities contains valuable information for utilities to better understand network performance and the weak links in the system. In this thesis, algorithms are developed to measure the contribution of individual equipment to the power system risk indices, as part of the novel risk analysis tool. A new cost worth approach was developed in this thesis that can make an early decision in planning for replacement activities concerning non-repairable aging components, in order to maintain a system reliability performance which economically is acceptable. The concepts, techniques and procedures developed in this thesis are illustrated numerically using published test systems. It is believed that the methods and approaches presented, substantially improve the accuracy of risk predictions by explicit consideration of the effect of equipment entering a period of increased risk of a non-repairable failure.

Is anybody there? Bootstrapping attendance with engagement

The report card for the introductory programming unit at our university has historically been unremarkable in terms of attendance rates, student success rates and student retention in both the unit and the degree course. After a course restructure recently involving a fresh approach to introducing programming, we reported a high retention in the unit, with consistently high attendance and a very low failure rate. Following those encouraging results, we collected student attendance data for several semesters and compared attendance rates to student results. We have found that interesting workshop material which directly relates to course-relevant assessment items and therefore drives the learning, in an engaging collaborative learning environment has improved attendance to an extraordinary extent, with student failure rates plummeting to the lowest in recorded history at our university.