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Three-dimensional printing is a revolutionary technology that is disrupting the status quo in surgery. It has been rapidly adopted by otolaryngology as a tool in surgical simulation for high-risk, low-frequency procedures. This systematic review comprehensively evaluates the contemporary usage of three-dimensional printed otolaryngology simulators.
A systematic review of the literature was performed with narrative synthesis.
Twenty-two articles were identified for inclusion, describing models that span a range of surgical tasks (temporal bone dissection, airway procedures, functional endoscopic sinus surgery and endoscopic ear surgery). Thirty-six per cent of articles assessed construct validity (objective measures); the other 64 per cent only assessed face and content validity (subjective measures). Most studies demonstrated positive feedback and high confidence in the models’ value as additions to the curriculum.
Whilst further studies supported with objective metrics are merited, the role of three-dimensional printed otolaryngology simulators is poised to expand in surgical training given the enthusiastic reception from trainees and experts alike.
This Prospective covers an overview of the injection molding process and the importance of mold design and tooling considerations, important material requirements and thermal properties for molds, polymer material requirements for injection molding, mold flow analysis, and the promise of using the 3D printing process for mold fabrication. The second part demonstrates the injection molding process using 3D-printed polymer molds and its suitability for low-run productions. 3D-printed molds using stereolithography and fused filament fabrication have been injected with polylactic acid, and the quality of the injected parts was assessed in terms of dimensional accuracy and the damage mechanisms during fabrication.
Maternal supraphysiological estradiol (E2) environment during pregnancy leads to adverse perinatal outcomes. However, the influence of oocyte exposure to high E2 levels on perinatal outcomes remains unknown. Thus, a retrospective cohort study was conducted to explore the effect of high E2 level induced by controlled ovarian stimulation (COH) on further outcomes after frozen embryo transfer (FET). The study included all FET cycles (n = 10,581) between 2014 and 2017. All cycles were categorized into three groups according to the E2 level on the day of the human Chorionic Gonadotropin trigger. Odds ratios (ORs) and their confidence intervals (CIs) were calculated to evaluate the association between E2 level during COH and pregnancy outcomes and subsequent neonatal outcomes. From our findings, higher E2 level was associated with lower percentage of chemical pregnancy, clinical pregnancy, ongoing pregnancy, and live birth as well as increased frequency of early miscarriage. Preterm births were more common among singletons in women with higher E2 level during COH (aOR1 = 1.93, 95% CI: 1.22–3.06; aOR2 = 2.05, 95% CI: 1.33–3.06). Incidence of small for gestational age (SGA) was more common in both singletons (aOR1 = 2.01, 95% CI: 1.30–3.11; aOR2 = 2.51, 95% CI: 1.69–3.74) and multiples (aOR1 = 1.58, 95% CI: 1.03–2.45; aOR2 = 1.99, 95% CI: 1.05–3.84) among women with relatively higher E2 level. No association was found between high E2 level during COH and the percentage of macrosomia or large for gestational age. In summary, oocyte exposure to high E2 level during COH should be brought to our attention, since the pregnancy rate decreasing and the risk of preterm birth and SGA increasing following FET.
Understanding changes in chemistry, microstructure, and physical properties during synthesis, processing, testing, and even service is vital for materials design and performance. Compared to traditional postmortem material characterization tools, in situ crystallographic characterization can provide considerable data and information on evolution of chemistry, dislocations, twinning, texture, and strains when a material is under external stimuli. Neutrons especially are able to probe material bulk properties and behaviors in extreme environments, thanks to their deep penetrating power and unique sensitivity to differentiate elements from lightweight to transition-metal atoms. In this article, we introduce and describe a diffractometer named VULCAN, which is located at Oak Ridge National Laboratory. This represents a powerful tool to understand materials properties and behaviors under complex environments, in particular, at high temperatures.
The coaxial compound helicopter with lift-offset rotors has been proposed as a concept for future high-performance rotorcraft. This helicopter usually utilizes a variable-speed rotor system to improve the high-speed performance and the cruise efficiency. A flight dynamics model of this helicopter associated with rotor speed governor/engine model is used in this article to investigate the effect of the rotor speed change and to study the variable rotor speed strategy. Firstly, the power-required results at various rotor rotational speeds are calculated. This comparison indicates that choice of rotor speed can reduce the power consumption, and the rotor speed has to be reduced in high-speed flight due to the compressibility effects at the blade tip region. Furthermore, the rotor speed strategy in trim is obtained by optimizing the power required. It is demonstrated that the variable rotor speed successfully improves the performance across the flight range, but especially in the mid-speed range, where the rotor speed strategy can reduce the overall power consumption by around 15%. To investigate the impact of the rotor speed strategy on the flight dynamics properties, the trim characteristics, the bandwidth and phase delay, and eigenvalues are investigated. It is shown that the reduction of the rotor speed alters the flight dynamics characteristics as it affects the stability, damping, and control power provided by the coaxial rotor. However, the handling qualities requirements are still satisfied with different rotor speed strategies. Finally, a rotor speed strategy associated with the collective pitch is designed for maneuvering flight considering the normal load factor. Inverse simulation is used to investigate this strategy on maneuverability in the Push-up & Pull-over Mission-Task-Element (MTE). It is shown that the helicopter can achieve Level 1 ratings with this rotor speed strategy. In addition, the rotor speed strategy could further reduce the power consumption and pilot workload during the maneuver.
Seasonal influenza virus epidemics have a major impact on healthcare systems. Data on population susceptibility to emerging influenza virus strains during the interepidemic period can guide planning for resource allocation of an upcoming influenza season. This study sought to assess the population susceptibility to representative emerging influenza virus strains collected during the interepidemic period. The microneutralisation antibody titers (MN titers) of a human serum panel against representative emerging influenza strains collected during the interepidemic period before the 2018/2019 winter influenza season (H1N1-inter and H3N2-inter) were compared with those against influenza strains representative of previous epidemics (H1N1-pre and H3N2-pre). A multifaceted approach, incorporating both genetic and antigenic data, was used in selecting these representative influenza virus strains for the MN assay. A significantly higher proportion of individuals had a ⩾four-fold reduction in MN titers between H1N1-inter and H1N1-pre than that between H3N2-inter and H3N2-pre (28.5% (127/445) vs. 4.9% (22/445), P < 0.001). The geometric mean titer (GMT) of H1N1-inter was significantly lower than that of H1N1-pre (381 (95% CI 339–428) vs. 713 (95% CI 641–792), P < 0.001), while there was no significant difference in the GMT between H3N2-inter and H3N2-pre. Since A(H1N1) predominated the 2018–2019 winter influenza epidemic, our results corroborated the epidemic subtype.
The extending market of concentrated solar power plants requires high-temperature materials for solar surface receivers that would ideally heat an air coolant beyond 1300 K. This work presents investigation on high-temperature alloys with ceramic coatings (AlN or SiC/AlN stacking) to combine the properties of the substrate (creep resistance, machinability) and coating (slow oxidation kinetics, high solar absorptivity). The first results showed that high-temperature oxidation resistance and optical properties of metallic alloys were improved by the different coatings. However, the fast thermal shocks led to high stress levels not compatible due to the differences in thermal expansion coefficients.
Economic pressures continue to mount on modern-day livestock farmers, forcing them to increase herds sizes in order to be commercially viable. The natural consequence of this is to drive the farmer and the animal further apart. However, closer attention to the animal not only positively impacts animal welfare and health but can also increase the capacity of the farmer to achieve a more sustainable production. State-of-the-art precision livestock farming (PLF) technology is one such means of bringing the animals closer to the farmer in the facing of expanding systems. Contrary to some current opinions, it can offer an alternative philosophy to ‘farming by numbers’. This review addresses the key technology-oriented approaches to monitor animals and demonstrates how image and sound analyses can be used to build ‘digital representations’ of animals by giving an overview of some of the core concepts of PLF tool development and value discovery during PLF implementation. The key to developing such a representation is by measuring important behaviours and events in the livestock buildings. The application of image and sound can realise more advanced applications and has enormous potential in the industry. In the end, the importance lies in the accuracy of the developed PLF applications in the commercial farming system as this will also make the farmer embrace the technological development and ensure progress within the PLF field in favour of the livestock animals and their well-being.
Population growth and rising incomes have led to increasing global demand for meat products. Meeting this demand without converting remaining natural ecosystems or further degrading ecosystems is one of the largest global sustainability challenges. A critical step to overcoming this challenge is to increase the productivity of livestock grazing systems, which occupy the largest land area of any type of agriculture globally. Integrated crop−livestock systems (iCL), which re-couple crop and livestock production at the farm scale, have been considered a promising strategy to tackle this challenge by restoring degraded pasturelands and providing supplemental nutrition to livestock. However, few studies have analyzed the economic viability of such systems, especially in Brazil, an important player in global food systems. This paper presents an economic analysis of iCL in Mato Grosso, Brazil, the largest grain and beef producer in the country, which spans the ecologically diverse Amazon, Cerrado and Pantanal biomes. We compare the economic performance of an integrated soybean/corn and beef cattle system to a continuous crop (soybean/corn) system and a continuous livestock (beef cattle) production system from 2005 to 2012. We use empirical case study data to characterize a ‘typical’ farm for each production system within the study region. We find that the integrated crop−livestock system has a higher annual net present value (NPV) per hectare (ha) than continuous cropping or livestock under a range of discount rates. However, under a scenario of substantially higher crop prices, the continuous cropping outperforms iCL. While iCL is not feasible in all regions of the Amazon and Cerrado, our results indicate that in places where the biophysical and market conditions are suitable for production, it could be a highly profitable way to intensify cattle production and potentially spare land for other uses, including conservation. Nevertheless, additional credit and technical support may be needed to overcome high upfront costs and informational barriers to increase iCL areas as a sustainable development strategy for agriculture in the Amazon and Cerrado regions.
Non-tuberculous mycobacterium encephalitis is rare. Since 2013, a global outbreak of Mycobacterium chimaera infection has been attributed to point-source contamination of heater cooler units used in cardiac surgery. Disseminated M. chimaera infection has presented many unique challenges, including non-specific clinical presentations with delays in diagnosis, and a high mortality rate among predominantly immunocompetent adults. Here, we describe three patients with fatal disseminated Mycobacterium chimaera infection showing initially non-specific, progressively worsening neurocognitive decline, including confusion, delirium, depression and apathy. Autopsy revealed widespread granulomatous encephalitis of the cerebrum, brain stem and spinal cord, along with granulomatous chorioretinitis. Cerebral involvement and differentiation between mycobacterial granulomas and microangiopathic changes can be assessed best on MRI with contrast enhancement. The prognosis of M. chimaera encephalitis appears to be very poor, but might be improved by increased awareness of this new syndrome and timely antimicrobial treatment.
This presentation will enable the learner to:
1.Describe the clinical, radiological and neuropathological findings of Mycobacterium chimaera encephalitis
2.Be aware of this rare form of encephalitis, and explain its diagnosis, prognosis and management
Staphylococcus aureus has been recognised as one of the important zoonotic pathogens. However, knowledge about the epidemiology and genetic characteristics of S. aureus in rabbits was limited. The aim of this study was to determine the characteristics of 281 S. aureus isolated from dead rabbits of nine rabbit farms in Fujian Province, China. All the isolates were characterised by multi-locus sequencing typing, detection of virulence factors and antimicrobial susceptibility test. The results showed that the 281 isolates were grouped into two sequence types, ST121 (13.52%, 38/281) and ST398 (86.48%, 243/281). Surprisingly, the ST121 strains were only recovered from the lung samples from one of the nine rabbit farms studied. In the 281 isolates, the virulence genes of nuc, hla, hlb, clfA, clfB and fnbpA were positive, whereas the sea, seb, tsst, eta and etb genes were negative. Notably, the 38 ST121 isolates carried the pvl gene. All the 281 isolates were methicillin-susceptible S. aureus, and the isolates were susceptible to most of the used antibiotics, except for streptomycin, kanamycin, azithromycin and penicillin, and the resistance rates of which were 23.84%, 19.57%, 16.01% and 11.03%, respectively. This study first described the epidemiology and characteristics of S. aureus in rabbits in Fujian Province, which will help in tracking the evolution of epidemic strains and preventing the rabbit–human transmission events.
Prior research has examined the firm-level performance implications of “busy” boards. Firm-level analysis, however, masks important heterogeneity in the time constraints and expertise of individual busy directors. We develop and validate shareholder voting as a proxy for shareholders’ satisfaction. Our director-specific tests provide compelling evidence that the potential costs of busy directors outweigh their benefits. At the same time, we uncover new sources of heterogeneity among busy directors. For example, the downsides are more pronounced for directors who sit on boards where fiscal year ends cluster in the same month. Our analysis highlights the role of shareholder voting in board composition research.
This review summarises the current literature on the role of microRNAs in presbyacusis (age-related hearing loss) and sudden sensorineural hearing loss.
Medline, PubMed, Web of Science and Embase databases were searched for primary English-language studies, published between 2000 and 2017, which investigated the role of microRNAs in the pathogenesis of presbyacusis or sudden sensorineural hearing loss. Quality of evidence was assessed using the National Institutes of Health quality assessment tool.
Nine of 207 identified articles, 6 of good quality, satisfied the review's inclusion criteria. In presbyacusis, microRNAs in pro-apoptotic and autophagy pathways are upregulated, while microRNAs in proliferative and differentiation pathways are downregulated. Evidence for microRNAs having an aetiological role in sudden hearing loss is limited.
A shift in microRNA expression, leading to reduced cellular activity and impaired inner-ear homeostasis, may contribute to the pathogenesis of presbyacusis.
To compare the epidemiologic features (e.g. settings and transmission mode) and patient clinical characteristics associated with outbreaks of different norovirus (Nov) strains, we retrospectively analysed data of Nov outbreaks occurring in Guangzhou, China from 2012 to 2018. The results suggested that outbreaks of Nov GII.2, GII.17 and GII.4 Sydney exhibited different outbreak settings, transmission modes and symptoms. GII.2 outbreaks mainly occurred in kindergartens, elementary and high schools and were transmitted mainly through person-to-person contact. By contrast, GII.4 Sydney outbreaks frequently occurred in colleges and were primarily associated with foodborne transmission. Cases from GII.2 and GII.17 outbreaks reported vomiting more frequently than those from outbreaks associated with GII.4 Sydney.
Optimizing the dietary calcium (Ca) level is essential to maximize the eggshell quality, egg production and bone formation in poultry. This study aimed to establish the Ca requirements of egg-type duck breeders from 23 to 57 weeks of age on egg production, eggshell, incubation, tibial, plasma and ovary-related indices, as well as the expression of matrix protein-related genes. Totally, 450 Longyan duck breeders aged 21 weeks of age were allotted randomly into five treatments, each with six replicates of 15 individually caged birds. The data collection started from 23 weeks of age and continued over the following 35 weeks. The five groups corresponded to five dietary treatments containing either 2.8%, 3.2%, 3.6%, 4.0% or 4.4% Ca. The tested dietary Ca levels increased (linear, P <0.01) egg production and egg mass, and linearly improved (P <0.01) the feed conversion ratio (FCR). Increasing the dietary Ca levels from 2.8% to 4.4% increased (P <0.01) the eggshell thickness and eggshell content. The tested Ca levels showed a quadratic effect on eggshell thickness and ovarian weight (P <0.01); the highest values were obtained with the Ca levels 4.0% and 3.6%, respectively. Dietary Ca levels affected the small yellow follicles (SYF) number and SYF weight/ovarian weight, and the linear response (P <0.01) was significant vis-à-vis SYF number. In addition, dietary Ca levels increased (P <0.05) the tibial dry weight, breaking strength, mineral density and ash content. Plasma and tibial phosphorus concentration exhibited a quadratic (P <0.01) response to dietary Ca levels. Plasma calcitonin concentration linearly (P <0.01) increased as dietary Ca levels increased. The relative expression of carbonic anhydrase 2 in the uterus rose (P <0.01) with the increment of dietary Ca levels, and the highest value was obtained with 3.2% Ca. In conclusion, Longyan duck breeders fed a diet with 4.0% Ca had superior eggshell and tibial quality, while those fed a diet with 3.6% Ca had the heaviest ovarian weights. The regression model indicated that the dietary Ca levels 3.86%, 3.48% and 4.00% are optimal levels to obtain maximum eggshell thickness, ovarian weight and tibial mineral density, respectively.