Wiener amalgam spaces are a class of function spaces where the function’s local and global behavior can be easily distinguished. These spaces are ex-tensively used in Harmonic analysis that originated in the work of ...Wiener amalgam spaces are a class of function spaces where the function’s local and global behavior can be easily distinguished. These spaces are ex-tensively used in Harmonic analysis that originated in the work of Wiener. In this paper: we first introduce a two-variable exponent amalgam space (L<sup>q</sup><sup>()</sup>,l<sup>p</sup><sup>()</sup>)(Ω). Secondly, we investigate some basic properties of these spaces, and finally, we study their dual.展开更多
This case report describes a woman aged approximately 50 years who has suffered from balance dysregulation and dizziness for more than 10 years. Although the subject underwent several examinations to confirm the etiol...This case report describes a woman aged approximately 50 years who has suffered from balance dysregulation and dizziness for more than 10 years. Although the subject underwent several examinations to confirm the etiology of her symptoms, the root cause remained unknown. The symptoms were thought to be caused by electromagnetic wave hypersensitivity because the subject experienced uneasiness and dizziness when a cell phone was held close to her body. A cell phone was used to diagnose the collection of harmful electromagnetic waves, and an amalgam filling was determined to be the cause. The amalgam filling was removed under strict protection, and the subject’s symptoms completely disappeared soon after the filling was removed.展开更多
Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramic...Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material(amalgam) with an equal material(resin composite) being more esthetic but also biologically questionable? For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of nonbiocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.展开更多
Objective: Conservative restoration principles that accurately reduce plaque accumulation are the goals of restorative dentistry. Correct and perfect restoration has an important effect on health of periodontious tiss...Objective: Conservative restoration principles that accurately reduce plaque accumulation are the goals of restorative dentistry. Correct and perfect restoration has an important effect on health of periodontious tissues. This study was done to compare the methods of oral hygiene, over hanged removal and restoration changing on periodontal health and alveolar bone height of restored mandible molars with proximal over hanged amalgam. Materials and Methods: All patients with over hanged amalgam restoration were randomly divided into three groups. In order to survey the effect of over hanged removal on gingival and bleeding indices and alveolar bone height adjacent to mandible molar teeth, these indices were determined according to recurrent radio-graphical early signs of alveolar bone loss during three months. Sixty patients, 20 in each group, were studied. In the group I, overhang was removed with ultrasonic scale or bur and oral hygiene methods as usual were continued. In the group II, over-hang was left, but plaque controls as the prophylaxis and flossing were done. In the group III, restoration was changed and oral hygiene was done as usual. Plaque index and bleeding index were measured at the beginning of study and three months later. Findings: Statistical analysis of studied indices at the beginning and three months after treatment using paired test has shown significant differences in gingival inflammation, in all groups. Statistical analysis of indices using Tukey HSD test has also shown significant differences in decreasing gingival inflammation measure when the over hanged restoration was removed. While there is no difference between the other two groups. Conclusion: The results showed that plaque control causes subsidence of gingival inflammation and increasing of alveolar bone support, and it is more effective when the over hanged restoration is changed.展开更多
Aim: To assess the knowledge and attitudes of dental practitioners regarding the disposal of amalgam waste from dental practices and to assess the level of mercury released via dental amalgam waste into the environmen...Aim: To assess the knowledge and attitudes of dental practitioners regarding the disposal of amalgam waste from dental practices and to assess the level of mercury released via dental amalgam waste into the environment in Trinidad and Tobago. Method: A questionnaire on dental wastewater discharge and amalgam waste disposal was administered to dental practitioners in Trinidad and Tobago. Levels of mercury in samples of wastewater and solid deposits obtained during removal of 160 amalgam fillings, were measured using Atomic Absorption Spectrometry. The numbers of amalgam fillings placed and removed over a monthly period from a random sample of dental practices in Trinidad and Tobago were also obtained via the questionnaires. The amount of mercury entering the environment from dental practices was estimated from these data. Results: Twenty per cent responded to the questionnaire. Thirty per cent of respondents used elemental mercury (from a dispenser), while 74.4% used pre-capsulated mercury for preparing amalgam fillings. Seventy nine per cent used chair-side traps and filters but none had amalgam separators in their surgery. Methods used to dispose of amalgam waste included disposal in the trash (48.8%), washing down the sink (39.5%);and as hazardous waste (37.2%). A mean concentration of 0.0759 ppm (or mg/L) mercury was found in filtrate from the wastewater samples. A total concentration of 3.4 g mercury per dentist per day was found to be released into the environment via dental amalgam waste in Trinidad and Tobago. Conclusion: Best management practices for disposal of dental amalgam waste are not generally followed. At 3.4 gms per day per dentist, the level of mercury released via dental amalgam waste into the environment in Trinidad and Tobago may be too high. Dental practitioners require education on the management of dental amalgam waste and national legislation to protect the environment from this source of mercury may be required.展开更多
Let M be a compact connected oriented 3-manifold with boundary, Q1, Q2 C 0M be two disjoint homeomorphic subsurfaces of cgM, and h ： Q1 → Q2 be an orientation-reversing homeomorphism. Denote by Mh or MQ1=Q2 the 3-ma...Let M be a compact connected oriented 3-manifold with boundary, Q1, Q2 C 0M be two disjoint homeomorphic subsurfaces of cgM, and h ： Q1 → Q2 be an orientation-reversing homeomorphism. Denote by Mh or MQ1=Q2 the 3-manifold obtained from M by gluing Q1 and Q2 together via h. Mh is called a self-amalgamation of M along Q1 and Q2. Suppose Q1 and Q2 lie on the same component F1 of δM1, and F1 - Q1 ∪ Q2 is connected. We give a lower bound to the Heegaard genus of M when M＇ has a Heegaard splitting with sufficiently high distance.展开更多
Municipal amalgamation has been done in many countries in recent years as the result of a push to enlarge the size and coverage of local government units, which in turn is driven mainly by the prospect of economies of...Municipal amalgamation has been done in many countries in recent years as the result of a push to enlarge the size and coverage of local government units, which in turn is driven mainly by the prospect of economies of scale. However, while municipality amalgamation or boundary reform raises population size, it introduces organizational changes in the local government that might increase administrative inefficiency. The choice for the method of integration of administrative functions before amalgamation might affect to public expenditure after amalgamation. This study uses Japanese municipal-level data and argues for a relation between the choice for the method of integration of administrative functions and cost inefficiency after amalgamation. The results show that the fully distributed facility method is more likely to be adopted in a larger administrative jurisdiction and in one with large differences in finances or political structures between amalgamated sub-regions. Moreover, the results of stochastic frontier regression show that new municipality adopting fully distributed facility method can possibly increase inefficiency by expanding organizational slack because the new administration system will be insufficient integration of administrative functions.展开更多
The main goal of this research is to investigate the effect of copper on compressive strength of dental amalgam. For this purpose amalgam capsules with two different content of copper were used. Cylindrical samples wi...The main goal of this research is to investigate the effect of copper on compressive strength of dental amalgam. For this purpose amalgam capsules with two different content of copper were used. Cylindrical samples with diameter to height ratio 1 to 2, were prepared via molding method. To evaluate the role of copper element on compressive strength, com-pression test was done at different strain rates i.e. 0.02, 0.2, 0.4 and 2 min–1. The results and microscopic evaluations showed that an increase in copper content in amalgam caused to eliminate gamma2 phase and leaded to promote compressive strength.展开更多
Silver amalgam contains mercury leading to concerns about the potential toxic effects of amalgam on the health of dental patients. The debate over the toxicity of silver amalgam restorations has divided the dental pro...Silver amalgam contains mercury leading to concerns about the potential toxic effects of amalgam on the health of dental patients. The debate over the toxicity of silver amalgam restorations has divided the dental profession for over a century. The use of amalgam restorations for anterior teeth have been declining worldwide due to patient's safety concerns and preference for tooth colored restorations. Nevertheless, amalgam has served the dental profession for decades and benefited hundreds of millions of patients because of its longevity as a dental restorative material. Amalgam is still the World's most widely used restorative material for posterior teeth.展开更多
Tembotrione is herbicide which belongs to the triketone group of herbicides. It’s registered as a selective, post-emergence herbicide developed for the control of a broad spectrum broadleaf and grassy weeds in corn. ...Tembotrione is herbicide which belongs to the triketone group of herbicides. It’s registered as a selective, post-emergence herbicide developed for the control of a broad spectrum broadleaf and grassy weeds in corn. There is little information about tembotrione because of his short presence in the market. Due to its ever wider application, it is important to know the details of its chemical characteristics and redox processes, including biogeochemical transformation and migration after application to agricultural land, which could contribute to its efficient and safer application. In this paper we examined voltammetric behavior of tembotrione using Silver/Amalgam (Ag/Hg) electrode. For the investigation of electrochemical behavior we used the cyclic voltammetry technique, with conventional three-electrode cell and electrochemical workstation. During the experiment pH values of solution varieties while constant concentration of tembotrione was maintained. Cyclic voltammograms were recorded at pH values 6, 8, 10 and 12, at which tembotrione was electrochemically active. At this pH values two signals were observed. Optimum pH value, at which the current intensity was greatest, was 12. Obtained results provide relevant information on the electrochemical behavior of tembotrione, which can serve as a basis for the development of electrochemical techniques for the removal and degradation of this pesticide in the environment.展开更多
文摘Wiener amalgam spaces are a class of function spaces where the function’s local and global behavior can be easily distinguished. These spaces are ex-tensively used in Harmonic analysis that originated in the work of Wiener. In this paper: we first introduce a two-variable exponent amalgam space (L<sup>q</sup><sup>()</sup>,l<sup>p</sup><sup>()</sup>)(Ω). Secondly, we investigate some basic properties of these spaces, and finally, we study their dual.
文摘This case report describes a woman aged approximately 50 years who has suffered from balance dysregulation and dizziness for more than 10 years. Although the subject underwent several examinations to confirm the etiology of her symptoms, the root cause remained unknown. The symptoms were thought to be caused by electromagnetic wave hypersensitivity because the subject experienced uneasiness and dizziness when a cell phone was held close to her body. A cell phone was used to diagnose the collection of harmful electromagnetic waves, and an amalgam filling was determined to be the cause. The amalgam filling was removed under strict protection, and the subject’s symptoms completely disappeared soon after the filling was removed.
文摘Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material(amalgam) with an equal material(resin composite) being more esthetic but also biologically questionable? For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of nonbiocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.
文摘Objective: Conservative restoration principles that accurately reduce plaque accumulation are the goals of restorative dentistry. Correct and perfect restoration has an important effect on health of periodontious tissues. This study was done to compare the methods of oral hygiene, over hanged removal and restoration changing on periodontal health and alveolar bone height of restored mandible molars with proximal over hanged amalgam. Materials and Methods: All patients with over hanged amalgam restoration were randomly divided into three groups. In order to survey the effect of over hanged removal on gingival and bleeding indices and alveolar bone height adjacent to mandible molar teeth, these indices were determined according to recurrent radio-graphical early signs of alveolar bone loss during three months. Sixty patients, 20 in each group, were studied. In the group I, overhang was removed with ultrasonic scale or bur and oral hygiene methods as usual were continued. In the group II, over-hang was left, but plaque controls as the prophylaxis and flossing were done. In the group III, restoration was changed and oral hygiene was done as usual. Plaque index and bleeding index were measured at the beginning of study and three months later. Findings: Statistical analysis of studied indices at the beginning and three months after treatment using paired test has shown significant differences in gingival inflammation, in all groups. Statistical analysis of indices using Tukey HSD test has also shown significant differences in decreasing gingival inflammation measure when the over hanged restoration was removed. While there is no difference between the other two groups. Conclusion: The results showed that plaque control causes subsidence of gingival inflammation and increasing of alveolar bone support, and it is more effective when the over hanged restoration is changed.
文摘Aim: To assess the knowledge and attitudes of dental practitioners regarding the disposal of amalgam waste from dental practices and to assess the level of mercury released via dental amalgam waste into the environment in Trinidad and Tobago. Method: A questionnaire on dental wastewater discharge and amalgam waste disposal was administered to dental practitioners in Trinidad and Tobago. Levels of mercury in samples of wastewater and solid deposits obtained during removal of 160 amalgam fillings, were measured using Atomic Absorption Spectrometry. The numbers of amalgam fillings placed and removed over a monthly period from a random sample of dental practices in Trinidad and Tobago were also obtained via the questionnaires. The amount of mercury entering the environment from dental practices was estimated from these data. Results: Twenty per cent responded to the questionnaire. Thirty per cent of respondents used elemental mercury (from a dispenser), while 74.4% used pre-capsulated mercury for preparing amalgam fillings. Seventy nine per cent used chair-side traps and filters but none had amalgam separators in their surgery. Methods used to dispose of amalgam waste included disposal in the trash (48.8%), washing down the sink (39.5%);and as hazardous waste (37.2%). A mean concentration of 0.0759 ppm (or mg/L) mercury was found in filtrate from the wastewater samples. A total concentration of 3.4 g mercury per dentist per day was found to be released into the environment via dental amalgam waste in Trinidad and Tobago. Conclusion: Best management practices for disposal of dental amalgam waste are not generally followed. At 3.4 gms per day per dentist, the level of mercury released via dental amalgam waste into the environment in Trinidad and Tobago may be too high. Dental practitioners require education on the management of dental amalgam waste and national legislation to protect the environment from this source of mercury may be required.
文摘Let M be a compact connected oriented 3-manifold with boundary, Q1, Q2 C 0M be two disjoint homeomorphic subsurfaces of cgM, and h ： Q1 → Q2 be an orientation-reversing homeomorphism. Denote by Mh or MQ1=Q2 the 3-manifold obtained from M by gluing Q1 and Q2 together via h. Mh is called a self-amalgamation of M along Q1 and Q2. Suppose Q1 and Q2 lie on the same component F1 of δM1, and F1 - Q1 ∪ Q2 is connected. We give a lower bound to the Heegaard genus of M when M＇ has a Heegaard splitting with sufficiently high distance.
文摘Municipal amalgamation has been done in many countries in recent years as the result of a push to enlarge the size and coverage of local government units, which in turn is driven mainly by the prospect of economies of scale. However, while municipality amalgamation or boundary reform raises population size, it introduces organizational changes in the local government that might increase administrative inefficiency. The choice for the method of integration of administrative functions before amalgamation might affect to public expenditure after amalgamation. This study uses Japanese municipal-level data and argues for a relation between the choice for the method of integration of administrative functions and cost inefficiency after amalgamation. The results show that the fully distributed facility method is more likely to be adopted in a larger administrative jurisdiction and in one with large differences in finances or political structures between amalgamated sub-regions. Moreover, the results of stochastic frontier regression show that new municipality adopting fully distributed facility method can possibly increase inefficiency by expanding organizational slack because the new administration system will be insufficient integration of administrative functions.
文摘The main goal of this research is to investigate the effect of copper on compressive strength of dental amalgam. For this purpose amalgam capsules with two different content of copper were used. Cylindrical samples with diameter to height ratio 1 to 2, were prepared via molding method. To evaluate the role of copper element on compressive strength, com-pression test was done at different strain rates i.e. 0.02, 0.2, 0.4 and 2 min–1. The results and microscopic evaluations showed that an increase in copper content in amalgam caused to eliminate gamma2 phase and leaded to promote compressive strength.
文摘Silver amalgam contains mercury leading to concerns about the potential toxic effects of amalgam on the health of dental patients. The debate over the toxicity of silver amalgam restorations has divided the dental profession for over a century. The use of amalgam restorations for anterior teeth have been declining worldwide due to patient's safety concerns and preference for tooth colored restorations. Nevertheless, amalgam has served the dental profession for decades and benefited hundreds of millions of patients because of its longevity as a dental restorative material. Amalgam is still the World's most widely used restorative material for posterior teeth.
基金This paper is supported by Serbian Ministry of Education and Science,project number 172030.
文摘Tembotrione is herbicide which belongs to the triketone group of herbicides. It’s registered as a selective, post-emergence herbicide developed for the control of a broad spectrum broadleaf and grassy weeds in corn. There is little information about tembotrione because of his short presence in the market. Due to its ever wider application, it is important to know the details of its chemical characteristics and redox processes, including biogeochemical transformation and migration after application to agricultural land, which could contribute to its efficient and safer application. In this paper we examined voltammetric behavior of tembotrione using Silver/Amalgam (Ag/Hg) electrode. For the investigation of electrochemical behavior we used the cyclic voltammetry technique, with conventional three-electrode cell and electrochemical workstation. During the experiment pH values of solution varieties while constant concentration of tembotrione was maintained. Cyclic voltammograms were recorded at pH values 6, 8, 10 and 12, at which tembotrione was electrochemically active. At this pH values two signals were observed. Optimum pH value, at which the current intensity was greatest, was 12. Obtained results provide relevant information on the electrochemical behavior of tembotrione, which can serve as a basis for the development of electrochemical techniques for the removal and degradation of this pesticide in the environment.
