Sean Peel, Dominic Eggbeer, Adrian Sugar and Peter Llewelyn Evans
Post-traumatic zygomatic osteotomy, fracture reduction, and orbital floor reconstruction pose many challenges for achieving a predictable, accurate, safe, and aesthetically…
Abstract
Purpose
Post-traumatic zygomatic osteotomy, fracture reduction, and orbital floor reconstruction pose many challenges for achieving a predictable, accurate, safe, and aesthetically pleasing result. This paper aims to describe the successful application of computer-aided design (CAD) and additive manufacturing (AM) to every stage of the process – from planning to surgery.
Design/methodology/approach
A multi-disciplinary team was used – comprising surgeons, prosthetists, technicians, and designers. The patient’s computed tomography scan data were segmented for bone and exported to a CAD software package. Medical models were fabricated using AM; for diagnosis, patient communication, and device verification. The surgical approach was modelled in the virtual environment and a custom surgical cutting guide, custom bone-repositioning guide, custom zygomatic implant, and custom orbital floor implant were each designed, prototyped, iterated, and validated using polymer AM prior to final fabrication using metal AM.
Findings
Post-operative clinical outcomes were as planned. The patient’s facial symmetry was improved, and their inability to fully close their eyelid was corrected. The length of the operation was reduced relative to the surgical team’s previous experiences. Post-operative scan analysis indicated a maximum deviation from the planned location for the largest piece of mobilised bone of 3.65 mm. As a result, the orbital floor implant which was fixed to this bone demonstrated a maximum deviation of 4.44 mm from the plan.
Originality/value
This represents the first application of CAD and AM to every stage of the process for this procedure – from diagnosis, to planning, and to surgery.
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Richard Bibb, Dominic Eggbeer, Peter Evans, Alan Bocca and Adrian Sugar
The computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to surgery…
Abstract
Purpose
The computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to surgery. To date guides have been produced using fragile materials via rapid prototyping techniques such as stereolithography (SLA), which typically require metal reinforcement to prevent damage from drill bits. The purpose of this paper is to report case studies which explore the application of selective laser melting (SLM) to the direct manufacture of stainless steel surgical guides. The aim is to ascertain whether the potential benefits of enhanced rigidity, increased wear resistance (negating reinforcement) and easier sterilisation by autoclave can be realised in practice.
Design/methodology/approach
A series of clinical case studies are undertaken utilising medical scan data, CAD and SLM. The material used is 316L stainless steel, an alloy typically used in medical and devices and surgical instruments. All treatments are planned in parallel with existing techniques and all guides are test fitted and assessed on SLA models of the patients' anatomy prior to surgery.
Findings
This paper describes the successful application of SLM to the production of stainless steel surgical guides in four different maxillofacial surgery case studies. The cases reported address two types of procedure, the placement of osseointegrated implants for prosthetic retention and Le Fort 1 osteotomies using internal distraction osteogenesis. The cases reported here have demonstrated that SLM is a viable process for the manufacture of custom‐fitting surgical guides.
Practical implications
The cases have identified that the effective design of osteotomy guides requires further development and refinement.
Originality/value
This paper represents the first reported applications of SLM technology to the direct manufacture of stainless steel custom‐fitting surgical guides. Four successful exemplar cases are described including guides for osteotomy as well as drilling. Practical considerations are presented along with suggestions for further development.
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Wimalin Rimpeekool, Martyn Kirk, Vasoontara Yiengprugsawan, Cathy Banwell, Sam-ang Seubsman and Adrian Sleigh
The purpose of this paper is to assess the usefulness of nutrition labels in Thailand during nutrition transition from traditional to modern diets that increase salt, sugar, and…
Abstract
Purpose
The purpose of this paper is to assess the usefulness of nutrition labels in Thailand during nutrition transition from traditional to modern diets that increase salt, sugar, and calorie intake and to note socio-demographic interactions and associations with consumption of transitional processed foods.
Design/methodology/approach
The authors studied 42,750 distance learning Open University adults aged 23-96 years in 2013 residing nationwide and participating in an ongoing community-based prospective cohort study. The authors used multivariable logistic regression to relate nutrition label experiences (“read”, “good understand”, “frequent use”), socio-demographic factors, and consumption of four transitional foods. These foods included “unhealthy” instant foods, carbonated soft drinks, and sweet drinks, or “healthy” milk.
Findings
Overall, two-thirds reported good understanding and frequent use of nutrition labels. Unhealthy transition-indicator processed foods were frequently consumed: instant foods (7 per cent), (carbonated) soft drinks (15 per cent), and sweet drinks (41 per cent). Frequent users of nutrition labels (e.g. females, older persons, professionals) were less likely to consume unhealthy indicator foods. Those with the most positive overall nutrition label experience (“read” + “good understanding” + “frequent use”) had the best indicator food profiles: instant foods (odds ratio (OR) 0.63; 95%CI, 0.56-0.70); soft drinks (OR 0.56; 95%CI, 0.52-0.61); sweet drinks (OR 0.79; 95%CI, 0.74-0.85); milk (OR 1.87; 95%CI, 1.74-2.00).
Originality/value
Knowledge protected – those with most nutrition label experience were least likely to consume unhealthy foods. Results support government regulated nutrition labels, expanding to include sweet drinks. The study is remarkable for its large size and nationwide footprint. Study subjects were educated, represent Thais of the future, and show high awareness of transition-indicator foods.
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Silvia Saravia-Matus, Jimmy Saravia Matus, Octavio Sotomayor and Adrian Rodriguez
The purpose of this paper is to review and examine the recent investment trends of firms operating in the food, feed and biofuel production and processing sectors in Latin…
Abstract
Purpose
The purpose of this paper is to review and examine the recent investment trends of firms operating in the food, feed and biofuel production and processing sectors in Latin America. The inter-related nature of these three sub-sectors and the great expansion they have gone through in the last decade showcases a series of socioeconomic and environmental policy challenges thus making it relevant to identify their different business models through a typology.
Design/methodology/approach
The paper first presents an unprecedented literature review based on field observations and media coverage of agri-business strategies of the food, feed and biofuel production in the region. It then moves to an in-depth analysis of investment operations that serve to classify such firms into a business model typology considering degree of internationalization and integration. The typology is a useful mechanism to enhance public policy analysis and uncover market or government incentives behind business decisions.
Findings
By focusing on investment strategies, the paper illustrates how both market and government incentives shape and affect the performance and consolidation of different players in the food, feed and biofuel sub-sectors in Latin America. The resulting effects have strong economic as well as social and environmental implications because such economic activities have an impact on global food and energy security.
Research limitations/implications
Limitations include a reliance on largely qualitative evidence and research methods due to unavailability of consistent numerical data in these specific agri-business sub-sectors.
Originality/value
This paper is unique in its focus on business models in a particularly relevant set of agri-business sub-sectors in Latin America and its implications to promote investment and innovation in value chain development while considering regional-specific challenges.
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Giada Danesi, Mélody Pralong and Vincent Pidoux
Drawing on ethnographic observations of diabetes (self-)management in French-speaking Switzerland and semi-structured interviews with healthcare practitioners, people living with…
Abstract
Drawing on ethnographic observations of diabetes (self-)management in French-speaking Switzerland and semi-structured interviews with healthcare practitioners, people living with diabetes and their relatives, the chapter aims at shedding light on self-tracking practices of people living with diabetes. It explores the ways people with diabetes measure and learn to recognise body symptoms of hypo- and hyperglycaemia through self-quantification, and act consequently. In particular, the chapter investigates recent medical devices – continuous and flash glucose monitoring systems – that reconfigure the work of health providers and self-care practices. It shows the self-monitoring practices and the resulting self-awareness people living with diabetes develop in interaction with technology and caregivers in order to undertake embodied actions. By pointing out that new technologies have facilitated the access to personal body information and the sharing of it, self-monitoring is also questioned as a form of surveillance, opening up issues of power and control over patients’ behaviours. With regard to this, the chapter illustrates that, occasionally, people with diabetes resist ‘docility’ through micro-powers at the level of everyday life by refusing to engage in their use and by developing personal strategies or ‘tactics’.
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In the periods, following the First and Second World Wars, colonial states across the British empire underwent waves of reforms that were geared toward improving human well-being…
Abstract
In the periods, following the First and Second World Wars, colonial states across the British empire underwent waves of reforms that were geared toward improving human well-being, from enhancing social conditions, such as health and education, to expanding opportunities for economic and political engagement. The literature on the colonial state typically traces these state-building efforts to the agency of European colonial officials. However, evidence from a historical analysis of Trinidad and Tobago reveals a different agent driving state reform: the colonized. A local labor movement during colonialism forced the colonial state to construct a number of state agencies to ameliorate the economic, political, and social conditions in the colony, thereby resulting in an increase in state capacity. This study, therefore, provides critical intervention into the colonial state literature by showing that the agency of the colonized, as opposed to just the colonizers, is key to state-building, and specifying the mechanisms by which the subaltern constrained colonial officials and forced them to enact policies that improved colonial state capacity.
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An odd‐sounding expression recently introduced into the language, derived from the passage of events, Privatization, introduced as a rescue operation for sections of public and…
Abstract
An odd‐sounding expression recently introduced into the language, derived from the passage of events, Privatization, introduced as a rescue operation for sections of public and nationalised industry to hand them over to private enterprise to avoid their destruction and smothering by the unholy wedlock of trade unionism and weak, inefficient management. It frequently met with the opposition of unions and sections of staff. Efforts have been made to sabotage the take‐over and operation of the services by private firms, occasionally making them impossible to operate. This elementary operation was expected to achieve even greater success in the sections taken over and reduced the room for destructive manoeuvring by ajitator, much of which was caused independent of the unions. In the public services some of the antics between rival factions bordered on the ludicrous.
Heat also facilitates the transmission of water through the cell walls, thereby assisting its passage from the interior to the surface of the material; it increases the vapour…
Abstract
Heat also facilitates the transmission of water through the cell walls, thereby assisting its passage from the interior to the surface of the material; it increases the vapour pressure of water, thus increasing its tendency to evaporate; and it increases the water‐vapour‐carrying capacity of the air. In the United States the unit of heat customarily used is the British thermal unit (B.t.u.), which for practical purposes is defined as the heat required to raise the temperature of a pound of water 1° F. Heat is commonly produced through the combustion of oil, coal, wood, or gas. Heating by electricity is seldom practicable because of its greater cost; but where cheap rates prevail it is one of the safest and most efficient, convenient and easily regulated methods. Direct heat, direct radiation and indirect radiation are the types of heat generally employed. Direct‐heating systems have the highest fuel or thermal efficiency. The mixture of fuel gases and air in the combustion chamber passes directly into the air used for drying. This method requires the use of special burners and a fuel, such as distillate or gas, which burns rapidly and completely, without producing soot or noxious fumes. The heater consists simply of a bare, open firebox, equipped with one or more burners, an emergency flue to discharge the smoke incidental to lighting, and a main flue, through which the gases of combustion are discharged into the air duct leading to the drying chamber. Direct‐radiation systems also are relatively simple and inexpensive and have a fairly high thermal efficiency. A typical installation consists of a brick combustion chamber with multiple flues, which carry the hot gases of combustion back and forth across the air‐heating chamber and out to a stack. The air is circulated over these flues and heated by radiation from them. The flues are made of light cast iron or sheet iron. The air‐heating chamber should be constructed of fireproof materials. The efficiency of the installation depends upon proper provision for radiation. This is attained by using flues of such length and diameter that the stack temperatures will be as low as is consistent with adequate draught. Heating the air by boiler and steam coils or radiators is an indirect‐radiation system, as the heat is transferred from the fuel to the air through the intermediate agency of steam. Such a system costs more to install and has a lower thermal efficiency than either of the other two systems. It is principally adapted to large plants operating over a comparatively long season on a variety of materials where the steam is needed to run auxiliary machinery or to process vegetables. Large volumes of air are required to carry to the products the heat needed for evaporation and to carry away the evaporated moisture. Insufficient air circulation is one of the main causes of failure in many dehydrators, and a lack of uniformity in the air flow results in uneven and inefficient drying. The fan may be installed to draw the air from the heaters and blow it through the drying chamber, or it may be placed in the return air duct to exhaust the air from the chamber. An advantage of the first installation is that the air from the heaters is thoroughly mixed before it enters the drying chamber. It has been claimed that exhausting the air from the chamber increases the rate of drying by reducing the pressure, but the difference is imperceptible in practice. Either location for the fan is satisfactory, and the chief consideration in any installation should be convenience. Close contact between the air and the heaters and between the air and the material is necessary for efficient transfer of heat to the air and from the air to the material, and to carry away the moisture. The increased pressure or resistance against which the fan must operate because of such contact is unavoidable and must be provided for, but at other points in the system every effort should be made to reduce friction. To this end air passages should be large, free from constrictions, and as short and straight as possible. Turns in direction should be on curves of such diameter as will allow the air to be diverted with the least friction. The general rule in handling air is that a curved duct should have an inside radius equal to three times its diameter. The water vapour present in air at ordinary pressures is most conveniently expressed in terms of percentage of relative humidity. Relative humidity is the ratio of the weight of water vapour actually present in a space to the weight the same space at the same temperature would hold if it were saturated. Since the weight of water vapour present at saturation for all temperatures here used is known, the actual weight present under different degrees of partial saturation is readily calculated from the relative humidity. Relative humidity is determined by means of two thermometers, one having its bulb dry and the other having its bulb closely covered by a silk or muslin gauze kept moist by distilled water. Tap water should not be used because the mineral deposits from it clog the wick, retard evaporation, and produce inaccurate readings. The wick must be kept clean and free from dirt and impurities. The two thermometers are either whirled rapidly in a sling or used as a hygrometer mounted on a panel with the wick dipping in a tube of water and the bulbs exposed to a rapid and direct current of air. The relative humidities corresponding to different wet‐ and dry‐bulb temperatures are ascertained from charts furnished by the instrument makers, or published in engineers' handbooks. As a general rule, the more rapidly the products have been dried the better their quality, provided that the drying temperatures used have not injured them. Some fruits and vegetables are more susceptible to heat injury than others, but all are injured by even short exposures to high temperatures. The duration of the exposure at any temperature is important, since injury can be caused by prolonged exposure at comparatively moderate temperatures. The rate of evaporation from a free water surface increases with the temperature and decreases with the increase of relative humidity of the air.
We have received a communication from Mr. A. H. Mitchell Muter, F.I.C., Public Analyst for Lambeth, with reference to the contamination of cheese as the result of it being wrapped…
Abstract
We have received a communication from Mr. A. H. Mitchell Muter, F.I.C., Public Analyst for Lambeth, with reference to the contamination of cheese as the result of it being wrapped in tinfoil.—Mr. Muter observes that the following facts are those upon which he based his remarks, re the potential danger to health arising from contamination by tin in cheese wrapped in this metal, contained in his report for the fourth quarter of 1929 to one of the Local Authorities for which he acts :—On 4th November, 1929, a Food Inspector to the Authority in question submitted an informal sample of wrapped cheese as the result of a complaint having been received from a ratepayer to the effect that he had been taken ill after partaking of it.—Mr. Muter's analysis showed it to contain 5·68 grains of tin per lb., and he therefore reported that he was of opinion that the ratepayer was fully justified in bringing the matter to the notice of the Inspector.—On 15th November a formal sample of wrapped cheese was submitted, which he found contained 6·89 grs. tin per lb., and he issued a report to this effect. As the result of this report he received on the 25th November five informal samples of various brands, all of which were found to contain tin varying from 0·28 to 6·34 grs. per lb., and a further three informal samples received on the 3rd December contained tin in quantities from 1·37 to 11·03 grs. per lb. On the 12th December a formal sample was submitted which contained as much as 14·8 grs. tin per lb.