bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheology of Thermoplastic Polyurethanes
Authors: Han Chang Dae 
Published: November 2020

Abstract
Thermoplastic polyurethane (TPU) has received considerable attention from both the scientific and industrial communities (Hepburn 1982; Oertel 1985; Saunders and Frish 1962). Applications for TPUs include automotive exterior body panels, medical implants such as the artificial heart, membranes, ski boots, and flexible tubing. Figure 10.1 gives a schematic that shows the architecture of TPU, consisting of hard and soft segments. Hard segments, which form a crystalline phase at service temperature, are composed of diisocyanate and short-chain diols as a chain extender, while soft segments, which control low-temperature properties, are composed of difunctional long-chain polydiols with molecular weights ranging from 500 to 5000. The soft segments form a flexible matrix between the hard domains. TPUs are synthesized by reacting difunctional long-chain diol with diisocyanate to form a prepolymer, which is then extended by a chain extender via one of two routes: (1) by a dihydric glycol chain extender or (2) by a diamine chain extender. The most commonly used diisocyanate is 4,4’-diphenylmethane diisocyanate (MDI), which reacts with a difunctional polyol forming soft segments, such as poly(tetramethylene adipate) (PTMA) or poly(oxytetramethylene) (POTM), to produce TPU, in which 1,4-butanediol (BDO) is used as a chain extender. There are two methods widely used to produce TPU: (1) one-shot reaction sequence and (2) two-stage reaction sequence. The reaction sequences for both methods are well documented in the literature (Hepburn 1982). It should be mentioned that MDI/BDO/PTMA produces ester-based TPU. One can also produce ether-based TPU when MDI reacts with POTM using BDO as a chain extender. TPUs are often referred to as “multiblock copolymers.” In order to have a better understanding of the rheological behavior of TPUs, one must first understand the relationships between the chemical structure and the morphology; thus, a complete characterization of the materials must be conducted. The rheological behavior of TPU depends, among many factors, on (1) the composition of the soft and hard segments, (2) the lengths of the soft and hard segments and the sequence length distribution, (3) anomalous linkages (branching, cross-linking), and (4) molecular weight.
Rheology of Particulate-Filled Polymers, Nanocomposites, and Fiber-Reinforced Thermoplastic Composites
Authors: Han Chang Dae 
Published: November 2020

Abstract
Polymer composites consisting of a thermoplastic polymer forming the matrix phase and a large amount of inorganic particles (commonly referred to as fillers) or glass fibers, which are often referred to as particulate-filled polymers, are very common in the plastics and elastomer’s industries (Deanin and Schott 1974; Kraus 1965; Lubin 1969). Polymer composites are developed to achieve a set of properties not possessed by the thermoplastic polymer (i.e., polymeric matrix) alone. Polymeric matrices can be thermoplastics, which soften and behave as viscous liquids when heated to above their glass transition temperatures (in the case of amorphous thermoplastic polymers) or above their melting temperatures (in the case of semicrystalline thermoplastic polymers). Polymeric matrices can also be thermosets, which undergo a transformation from a viscous resinous liquid to a hard or rubbery solid in the presence of heat and/or curing agents. There are numerous industrial products made of particulate-filled polymeric materials; for example, thermoplastic polymers filled with mica or calcium carbonate, carbon-black-filled elastomers, thermoplastic polymers or thermosets reinforced with glass fibers or carbon fibers. The ultimate goal of adding fillers to a thermoplastic polymer and adding glass fiber or carbon fiber to a thermoset is to improve the mechanical properties of the polymer. However, fillers, glass fibers, or carbon fibers themselves usually supply little or no reinforcement since there is little interfacial interaction between a thermoplastic polymer and fillers, and between a thermoset and glass fiber or carbon fiber. This has led to the development of “coupling agents,” chemical additives capable of improving the interfacial bonds between a thermoplastic polymer and fillers, and between a thermoset and glass fibers or carbon fibers (Plueddemann 1982). The use of coupling agents for the surface modification of fillers to reinforce thermoplastics has generally been directed towards improving the mechanical strength and chemical resistance of composites by improving adhesion across the interface. When inorganic fillers or glass fibers are added to a thermoplastic polymer, the resulting material exhibits a complex rheological behavior, quite different from the rheology of neat homopolymers presented in Chapter 6.
Treatment of dental caries in the preschool child
Authors: Fayle S A , Kandiah P 
Published: November 2020

Abstract
Dental caries is still one of the most prevalent pathological conditions in the child population of most Western countries. A UK study of children aged from 1.5 to 4.5 years demonstrated that 17% have decay, and a more recent survey of 3-year-old children in England found 12% to have decay with up to a third of 3-year-olds affected in the worst areas of the country (Public Health England 2014). Although the most recent surveys show a slow decline in decay levels, on average 25% of five-year-old children have decay, peaking at over 50% in the worst affected parts of England. Dental caries is associated with significant morbidity in children, and the treatment of dental caries (and its sequelae) is currently the most common reason for administration of general anaesthesia (GA) to children in the UK. Successfully managing decay in very young children presents the dentist with a number of significant challenges. This Chapter will outline approaches to the management of the preschool child with dental caries. Early childhood caries (ECC) is a term used to describe dental caries presenting in the primary dentition of young children. Terms such as ‘nursing bottle mouth’, ‘bottle mouth caries’, or ‘nursing caries’ are used to describe a particular pattern of dental caries in which the upper primary incisors and upper first primary molars are usually most severely affected. The lower first primary molars are also often carious, but the lower incisors are usually spared—being either entirely caries free or only mildly affected. Some children present with extensive caries that does not follow the ‘nursing caries’ pattern. Such children often have multiple carious teeth and may be slightly older (3 or 4 years of age) at initial presentation. This presentation is sometimes called ‘rampant caries’. However, there is no clear distinction between rampant caries and nursing caries, and the term ‘early childhood caries’ is widely recognized as a suitable all-encompassing term. In many cases, ECC is related to the frequent consumption of a drink containing sugars from a bottle or ‘dinky’ type comforters (these have a small reservoir that can be filled with a drink).
Advanced restorative dentistry
Authors: Kilpatrick N M , Burbridge L A L 
Published: November 2020

Abstract
The aim of this Chapter is to cover the management of more complicated clinical problems associated with children and adolescents: tooth discolouration, inherited enamel and dentine defects, hypodontia, and tooth surface loss. As there is considerable overlap in the application of the various restorative techniques, the Chapter is divided into two parts. The first outlines the clinical steps involved in the various procedures, while the second covers the more general principles of management of particular dental problems. It is not the remit of this Chapter to cover advanced restorative dentistry in detail, but many of the techniques and indications used in children are the same as those for adults (Boxes 11.1 and 11.2). With the aid of some clinical examples, eight of the restorative procedures will be described in simple stages. Omitted from this list are the stages involved in the provision of full crown restorations and bridgework, which are the specific remit of a restorative dentistry textbook. However, the provision of porcelain veneers, more commonly associated with adult patients, will be mentioned briefly. This technique involves the daily placement of carbamide peroxide gel into a custom-fitted tray on either the upper or the lower arch. As the name suggests, it is carried out by the patient at home and is initially done on a daily basis. • Mild fluorosis. • Moderate fluorosis as an adjunct to hydrochloric acid–pumice micro-abrasion. • Yellowing of ageing. • Single teeth with sclerosed pulp chambers and canals. • Selective bleaching for aesthetic purposes. • Upper impression and working model. • Soft mouthguard—avoiding the gingival tissues. • 10% carbamide peroxide gel. 1. Take an alginate impression of the arch to be treated and cast a working model in stone. 2. Relieve the labial surfaces of the teeth by about 0.5mm and make an acrylic pull-down vacuum-formed splint as a mouthguard with or without reservoirs for bleaching agent on the teeth requiring lightening. The splint should be no more than 2mm thick and should not cover the gingival tissues. It is only a vehicle for the bleaching gel and is not intended to protect the gingivae.
Periodontal diseases in children
Authors: Heasman P A , Waterhouse P J 
Published: November 2020

Abstract
Periodontal diseases comprise a group of infections that affect the supporting structures of the teeth: marginal and attached gingiva, periodontal ligament, cementum, and alveolar bone. Acute gingival diseases—primarily herpetic gingivostomatitis and necrotizing gingivitis—are ulcerative conditions that result from specific viral and bacterial infection. Chronic gingivitis, however, is a non-specific inflammatory lesion of the marginal gingiva which reflects the bacterial challenge to the host when dental plaque accumulates in the gingival crevice. The development of chronic gingivitis is enhanced when routine oral hygiene practices are impaired. Chronic gingivitis is reversible if effective plaque control measures are introduced. If left untreated, the condition invariably converts to chronic periodontitis, which is characterized by resorption of the supporting connective tissue attachment and apical migration of the junctional epithelia. Slowly progressing, chronic periodontitis affects most of the adult population to a greater or lesser extent, although the early stages of the disease are detected in adolescents. Children are also susceptible to aggressive periodontal diseases that involve the primary and permanent dentitions, and present in localized or generalized forms. These conditions, which are distinct clinical entities affecting otherwise healthy children, must be differentiated from the extensive periodontal destruction that is associated with certain systemic diseases, degenerative disorders, and congenital syndromes. Periodontal tissues are also susceptible to changes that are not, primarily, of an infectious nature. Factitious stomatitis is characterized by self-inflicted trauma to oral soft tissues and the gingiva are invariably involved. Drug-induced gingival enlargement is becoming increasingly prevalent with the widespread use of organ transplant procedures and long-term immunosuppressant therapy. Localized enlargement may occur as a gingival complication of orthodontic treatment. A classification of periodontal diseases in children is given in Table 12.1. Marginal gingival tissues around the primary dentition are more highly vascular and contain fewer connective tissue fibres than tissues around the permanent teeth. The epithelia are thinner with a lesser degree of keratinization, giving an appearance of increased redness that may be interpreted as mild inflammation. Furthermore, the localized hyperaemia that accompanies eruption of the primary dentition can persist, leading to swollen and rounded interproximal papillae and a depth of gingival sulcus exceeding 3mm.
Anomalies of tooth formation and eruption
Authors: Parekh S , Harley K 
Published: November 2020

Abstract
Both the primary and permanent dentitions may be affected by variations in the number, size, and form of the teeth, as well as the structure of the dental hard tissues. These variations may be exclusively genetically determined, brought about by either local or systemically acting environmental factors, or possibly a combination of both genetic and environmental factors acting together. The same interplay of influences may affect the eruption and exfoliation of primary teeth, as well as the eruption of permanent teeth. This Chapter considers a range of conditions involving abnormalities of the number, size, form, and structure of teeth and their eruption. It is important to be aware of the psychosocial aspect when meeting children and families affected by these conditions. We have too often heard stories of social isolation of even very young children as a result of their missing or discoloured teeth. In the case of discoloured teeth, parents and children have told us that they have been told off or teased for not looking after their teeth when the discolouration was intrinsic and unavoidable. Society’s preoccupation with ‘the perfect smile’ seems to increase; hence children denied access to aesthetic dental treatment may be genuinely disadvantaged. Wherever possible, we try to avoid the use of the word ‘normal’ in our clinical care, although the word will be used in this text. The vast majority of children with these conditions want to become ‘one of the crowd’. Thus we would speak, when offering restorative treatment for example, of making a smile ‘ordinary’ or ‘boring’. While investigating inherited conditions, it is important to make enquiries of both sides of the family tree equally. Not only does this ensure that the investigation is complete, but also it may help to alleviate any sense of ‘guilt’ felt by an affected parent. We have been questioned repeatedly about the possibility of genetic treatment for some of these inherited conditions. We are not aware of any progress in this direction at present. Hypodontia is the term most often applied to a situation where a patient has up to six missing teeth (excluding third permanent molars) as a result of their failure to develop.
The paedodontic–orthodontic interface
Authors: Gillgrass T J , Keightley A J 
Published: November 2020

Abstract
The long-term management of a child’s developing occlusion often benefits greatly from a good working relationship between the paediatric dentist and the orthodontist. Typical problems range from minimizing damage to the occlusion caused by enforced extraction of poor-quality teeth, through the management of specific local abnormalities such as impacted teeth, to referral for comprehensive treatment of all aspects of the malocclusion. This Chapter discusses the principles underlying when to refer to a specialist colleague, and looks at some common clinical situations where collaboration is often needed. From the age of 8 years all children should be screened for the presence of malocclusion when they attend for a routine dental examination. Although orthodontic treatment is usually carried out in the late mixed and early permanent dentition, some conditions benefit from treatment at an earlier stage. The screening need only be a brief clinical assessment, but it should be carried out systematically to ensure that no important findings are overlooked. An outline of a basic orthodontic assessment is given in Table 15.1. With practice this can be carried out quite quickly to give an overall impression of the nature and severity of a malocclusion. In essence, it comprises assessments of the following elements: • the patient’s awareness of their malocclusion (the complaint, if any) • their general level of dental awareness • an extra-oral examination of facial form (skeletal pattern and soft tissues) • general oral condition—oral hygiene, periodontal health, caries risk, and tooth quality • the presence or absence of all teeth • the alignment and form of each arch • the teeth in occlusion. Radiographs are not routinely used when screening for the presence of malocclusion and should only be taken when there is a clinical indication. A panoramic radiograph gives a useful general scan of the dentition and indicates the presence or absence of teeth. Modern digital panoramic radiographs are generally of good enough quality to assess for the presence of any abnormalities or gross caries. Intra-oral views may be indicated if specifically indicated by the history/examination (e.g. dental trauma) or for further investigation of pathology found on a panoramic image. A radiographic assessment must always be made when considering any extractions.
Medical disability
Authors: Hosey M T , Welbury R 
Published: November 2020

Abstract
There are many general medical conditions that can directly affect the provision of dental care and some where the consequences of dental disease, or even dental treatment, can be life-threatening. The increasing number of children who now survive with complex medical problems because of improvements in medical care present difficulties in oral management. Dental disease can have grave consequences and so rigorous prevention is paramount. The decline in childhood mortality has led to increasing emphasis on maintaining and enhancing the quality of the child’s life and ensuring that children reach adult life as physically, intellectually, and emotionally healthy as possible. Dental care can play an important part in enhancing this quality of life. Indeed, management within the primary dental services helps to ‘normalize’ life for these children who appreciate attending along with their family, even though sometimes they might still require specialist expertise. Although infant mortality rates (deaths under 1 year of age) have declined dramatically in the UK, death rates are still higher in the first year of life than in any other single year below the ages of 55 in males and 60 in females. The rates are highest for the very young. The main causes of death in the neonatal period (the first 4 weeks of life) are associated with prematurity (over 40%) and congenital malformations (30%). However, in the remainder of the first year the main causes of death occur at home and often nothing abnormal or suspicious is found (SUDI (sudden unexpected death in infancy) and SIDS (sudden infant death syndrome). Although the unexpected death of a child over 1 year of age is rare, a few infants still succumb to respiratory and other infective diseases (e.g. meningitis), congenital malformations, and accidents. (See Key Points 17.1.) All patients should have an accurate medical history taken before any dental treatment is undertaken. This is important for several reasons. 1. To identify any medical problems that might require modification of dental treatment. 2. To prioritize children who require intensive preventive dental care. 3. To identify children requiring prophylactic antibiotic cover for potentially septic dental procedures.
Resuscitation and transfer
Authors: Whymark Caroline , Junkin Ross , Ramsey Judith 
Published: November 2020

Abstract
To pass the written part of the FRCA, candidates must achieve the pass mark for the SAQs and the MCQ/ SBA papers combined. Therefore, doing particularly well in one paper, or one area, can compensate for another in which you have scored poorly. The 30 SBA questions is an area that candidates commonly find difficult. There is a feeling these questions are unjust and that it is impossible to second guess the examiners and choose the correct option. They feel further punished that four marks are awarded for each correct answer or lost for an incorrect choice. While this reflects the fact that four answers have been eliminated in the course of choosing the best answer, candidates often state it is an unfair ‘all or nothing’ way to mark these questions. They can commonly narrow the choice down to a final two options but report finding it difficult to then choose between them. They receive no credit having successfully eliminated three of the options and cite the SBA element as being the reason they failed the examination. These comments however are not supported by examination success data published by the RCoA. The pass rate for this paper was consistent at around 70% before and after the introduction of the SBA component in September 2011. We believe the concepts behind the SBAs are misunderstood by many. When asked to write a SBA question, candidates inevitably produce a five- part A to E multiple choice question but with only one correct answer. The finer points of SBA questions are lost among quickly written revision aids containing what the authors believe to be examination standard questions, when often they are not. Further, because SBAs are a relatively new element to the FRCA there is a limited bank of questions, and a highly restricted number in the public domain. Both these factors make practice of these questions difficult. Part of exam success is practice of the technique and question type in advance. We believe the practice of SBAs is an area to which candidates do not give enough attention.
The AI Delusion
Authors: Smith Gary 
Published: November 2020

Abstract
We live in an incredible period in history. The Computer Revolution may be even more life-changing than the Industrial Revolution. We can do things with computers that could never be done before, and computers can do things for us that could never be done before. But our love of computers should not cloud our thinking about their limitations. We are told that computers are smarter than humans and that data mining can identify previously unknown truths, or make discoveries that will revolutionize our lives. Our lives may well be changed, but not necessarily for the better. Computers are very good at discovering patterns, but are useless in judging whether the unearthed patterns are sensible because computers do not think the way humans think. We fear that super-intelligent machines will decide to protect themselves by enslaving or eliminating humans. But the real danger is not that computers are smarter than us, but that we think computers are smarter than us and, so, trust computers to make important decisions for us. The AI Delusion explains why we should not be intimidated into thinking that computers are infallible, that data-mining is knowledge discovery, and that black boxes should be trusted.