A fluoride releasing dental prosthesis copolymer for oral biofilm control

PhD ThesisMicrobial biofilms on removable oral appliances can act as reservoirs for pathogens that contribute to oral diseases such as candidiasis and root caries. In this study, we evaluated the efficacy of a new fluoride-releasing copolymer on biofilms formed by three acidogenic microorganisms, C. albicans, S. mutans and L. casei. In all experiments, two materials were studied: chemically-activated copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate with polymethyl methacrylate powder. For one group, 30% NaF was added at the expense of some of the PMMA. The effect that autoclaving had on important parameters such as chemical composition, roughness and fluoride release was analysed. Samples were fitted into two polysulfone Modified Robbins Devices. Single- and mixed-species biofilms were cultured for 48 h, harvested, and microorganisms were quantified by total viable counts and quantitative PCR. The pH was monitored during mixed species biofilm formation. Autoclaving did not alter the chemical composition of either material, as measured by infra-red spectroscopy. However, it did cause a significant increase in roughness of the fluoridated materials (T-test, p300 μg/cm2.day) were released from fluoridated samples for up to 6 days, followed by low levels of release for 6 months. The inclusion of fluoride within the copolymer significantly reduced colonisation by C. albicans, S. mutans and L. casei in mixed-species biofilms (T-test, p0.05) reduced. Fluoride suppressed the acidogenicity of biofilms for up to 24 h. In conclusion, a fluoride-releasing copolymer has been developed to inhibit the growth of acidogenic oral biofilms in vitro. The copolymer potentially has major benefits for oral healthcare in wearers of removable oral appliances

Cooling and Refrigeration Solar Systems

 Photovoltaic (PV) Energy Systems and Thermal Energy Systems have been used for decades for the purposes of generating electricity and thermally needed processes. These systems are expanding more and more every year alongside the emerging new researches results aiming at the development of the different systems to provide the needs of cooling and refrigeration fields in general. This report will present the different available methods, materials and system's design of the cooling and refrigeration. Although in practice solar cooling and refrigeration are nearly the same process, but usually either the material, the methods or temperature ranges are different

Study of Mechanical Behavior of Friction Welded Joint in a Brass Material and Its Statistical Modelling

ABSTRACT: Friction welding is used in many fields because the procedure is easily automated and it is I. Statistical Modelling Taguchi design:- A Taguchi Design or an orthogonal array is a method of designing experiments that usually requires only a fraction of the full factorial combinations. An orthogonal array means the design is balanced so that factor levels are weighted equally. Because of this, each factor can be evaluated independently of all the other factors, so the effect of one factor does not influence the estimation of another factor.In robust parameter design, you first choose control factors and their levels and choose an orthogonal array appropriate for these control factors. The control factors comprise the inner array. At the same time, you determine a set of noise factors, along with an experimental design for this set of factors. The noise factors comprise the outer array.The experiment is carried out by running the complete set of noise factor settings at each combination of control factor settings (at each run). The response data from each run of the noise factors in the outer array are usually aligned in a row, next to the factors settings for that run of the control factors in the inner array. For an example, see data for analysis using Taguchi design L9 (3**4) L9 (3**4) REPRESENTS:- L9 9 RUNS 3 3 LEVELS 4 4FACTORS The following are the 3 Levels which are considered in Taguchi design High 3 Medium 2 Low 1 Experimentation Preparation of specimen: This project involves the experimental study on friction welding of similar material of brass. For all the friction welding system, rotational speed, friction pressure, forge pressure applied to the parts and friction time are the principle controlling variables which influence the metallurgical and mechanical properties of friction welded joints. These similar joints thus prepared with friction welding techniques have been studied for tensile strength and up set values

Tuning Methods Of Pid Controller For Dc Motor Speed Control

The traditional PID controllers are used for a long time to control the DC motor for many industrial processes, that because of the simplicity, flexibility, and satisfactory performance of this type of controller. This paper discusses the basic PID tuning method (Ziegler-Nichols) and its modification (Chien-Hrones-Reswick). Also, analysis the speed control DC motor response using the PID controller parameters that result from the tuning methods mentioned earlier. Moreover, explain the advantage and disadvantage of each formula of these methods. GUL/MATLAB windows used to implementing both methods to create more comfortable and friendly environment for better understanding of the PID controller tuning methods formula for engineering students and practicing engineers

Awake Nasal Fiberoptic Intubation in Diffuse Para-pharyngeal Abscess

This is a case report on awake fibreoptic intubation for a patient with a deep neck space infection. Intubation in this group of patients is considered difficult. It is challenging to anaesthesiologists, emergency physicians and otorhinolaryngologists because there is no consensus for airway management in these patients. We present a 30-year-old gentleman with swelling over the right cheek, difficulty breathing and severe trismus. He had a history of toothache one month prior to admission. Upon clinical examination, there was a diffuse swelling over the right mandible. Other examinations were unremarkable. Provisional diagnosis of a right para-pharyngeal abscess was made secondary to a possible infected right lower 3rd molar, with a differential diagnosis of a right parotid abscess with para-pharyngeal extension. Radiological assessment using computed tomography (CT) of the head and neck region showed an abscess over the right para-pharyngeal area, soft palate and right submandibular region. The narrowest part of the airway was at the region posterior to the soft palate, measuring approximately 1 cm. All staff and equipment were prepared for intubating a difficult airway. The patient was transferred to the control environment (operation theatre) for intubation. Awake nasal fibreoptic intubation (AFOI) was successfully performed for this patient using intravenous dexmedetomidine alone as the sedative

Comparison Study Of Energy Efficiency Activities Programs Among The Selected Region And Countries: Lessons Learned For Malaysia

This study reviews the contemporary tendencies in energy efficiency performance in chosen regions and countries. It also reviews the energy efficiency strategies and activities accomplished in these countries which pursue the program of reduction in energy consumption while maintaining the comfort level. These become the objectives and today’s energy efficiency requirement. This study also aims to highlight these activities and the outcomes of the energy efficiency implementation. The extent of this action and its effectiveness is being ascertained. The indicator used to evaluate the Energy Efficiency activities is the Energy Intensity Indicator which is provided by International Energy Agency (IEA). The reports and measurements of the International Energy Agency (IEA) are considered in order to make comparison among the selected countries. The main reason of focus on Energy Intensity levels is because this indicator reflects the result of all activities in different sectors and make sense which country has fulfilled the requirement of Energy Efficiency. The regions and countries are selected on the basis that their level of achievement in the energy efficiency programs are high. However, comparison is still made because each region and country has different emphasis and focus. Despite that Malaysia is a developing country, the achievement towards satisfactory energy efficiency implementation can be considered as encouraging and can only advance further if energy efficiency practice in these selected countries will be learned

Permeance Based Algorithm For Computation Of Flux Linkage Characteristics Of Non-Linear 6/4 Switched Reluctance Motor (SRM)

The concept of permeance is used in the analysis of flux linkage of 6/4 SRM. The aim of this paper is to develop an efficient algorithm exploiting the nonlinear feature of the 6/4 SRM using the aforementioned concept of permeance. The first step is to generate the relevant equations related to permeances of the 6/4 SRM under study. The 6/4 SRM’s magnetization curve is then derived from the summation of mmf drops at various blocks representing the motor. The air gap permeances are derived at various angles and 3-D leakage effects are taken into account. These permeances are used for the mmf drop computation. The algorithm is capable of efficiently computing mmf drop at every block to consequently yield a complete accurate nonlinear flux linkage feature of the 6/4 switched reluctance motor. In this way, the capability of the SRM to produce the expected four times the specific output torque due to operation in high saturation region compared to an equivalent induction motor as special the attribute of the SRM is demonstrated

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Is being big...better? : a study of Norwegian saving banks

This study examines the relationship between size and financial efficiency, existence of economies of scale in the context of Norwegian saving banking sector in the span of nine years from 2002 to 2010. The study has used longitudinal data which is secondary data in its nature and is obtained from the Norwegian saving banks association. Multiple regressions have been applied in order to find the nature and significance of relationship, and polynomial regression is used to demonstrate the curvilinear relationship. Total assets and deposits are used as a dimension of size; operating expense ratio is used as efficiency measurement. Our results reveal that there is a complex association between size and efficiency. We observed that operating costs decrease as the size increases, but this phenomenon does not hold continuously and larger banks experience diseconomies of scale. Our findings suggest that with the increase in size the banks enjoy economies of scale, but the larger banks start experiencing diseconomies of scale, and then very large banks start experiencing economies of scale again

Survey Of Nonlinear Schrödinger Equations With Harmonic Potential

A study of the initial value problems of some nonlinear Schrödinger equations is presented, as well as a study of local wellposedness. We elaborated on local wellposedness in both H^s and H^1 Sobolev spaces. For the Cauchy problem with harmonic potential, we studied the geometric pattern of the profiles of the solutions in a quantum mechanical model and its application using two explicit operators