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Female anaesthetists in early training commonly question whether their strength is adequate for tracheal intubation. This study investigated the influence of gender and experience on intubation ability and laryngoscopic technique. A manikin model and purpose-designed force-transducing laryngoscope was used to test three cohorts at different levels of experience (novice, intermediate and experienced males and females, n = 65) for the axial force and torque exerted, best laryngoscopic view obtained, success with and time for intubation and laryngoscopic technique. There were no significant differences between novice or experienced female and male intubators in markers of their ability to intubate or in the forces generated. For novice females compared with novice males, mean success rate was 90% (80.2 to 99.9) versus 97% (91.1 to 100, P = 0.29); and mean time to intubate 24 seconds (19 to 29 seconds) versus 18 seconds (14 to 21 seconds, P = 0.057). With experience, the forces generated during intubation reduced and ability improved. Proximal laryngoscope grips (close to the blade) generated lower forces than distal grips. Female and male intubators did not differ in ability to intubate or in the forces they exerted during direct laryngoscopy. [ABSTRACT FROM AUTHOR]

Objective:  The aim of the study was to determine the effect of a short and long working length screw configuration on construct stiffness and plate strain in a synthetic, short fragment, small gap fracture model stabilized with a 12-hole 3.5-mm locking compression plate (LCP)., Study Design:  Six replicates of short and long working length constructs on a short fragment, small gap fracture model underwent four-point bending. Construct stiffness and plate strain were compared across working length and along the plate., Results:  With the LCP on the compression surface (compression bending), the short working length had a significantly higher construct stiffness and lower plate strain than the long working length. Conversely, with the LCP on the tension surface (tension bending), transcortical contact between 150 and 155 N induced load sharing at the fracture gap, which significantly increased construct stiffness and decreased plate strain in the long working length. At 100 N (precontact), the short working length had a significantly higher construct stiffness and lower plate strain than the long working length, comparable with our compressing bending results., Conclusion:  In compression bending, and before transcortical contact occurred in tension bending, the short working length had a significantly higher construct stiffness and lower plate strain than the long working length. Load sharing due to transcortical contact observed in our model in tension bending will vary with fracture gap, working length, and loading condition. These results must be interpreted with caution when considering clinical relevance or potential in vivo biomechanical advantages., Competing Interests: None declared., (Thieme. All rights reserved.)

This study evaluated multiple commercially available continuous monitoring (CM) point sensor network (PSN) solutions under single-blind controlled release testing conducted at operational upstream and midstream oil and natural gas (O&G) sites. During releases, PSNs reported site-level emission rate estimates of 0 kg/h between 38 and 86% of the time. When non-zero site-level emission rate estimates were provided, no linear correlation between the release rate and the reported emission rate estimate was observed. The average, aggregated across all PSN solutions during releases, shows 5% of the mixing ratio readings at downwind sensors were greater than the site's baseline plus two standard deviations. Four of seven total PSN solutions tested during this field campaign provided site-level emission rate estimates with the site average relative error ranging from -100% to 24% for solution D, -100% to -43% for solution E, -25% for solution F (solution F was only at one site), and -99% to 430% for solution G, with an overall average of -29% across all sites and solutions. Of all the individual site-level emission rate estimates, only 11% were within ±2.5 kg/h of the study team's best estimate of site-level emissions at the time of the releases.

Background: Non-unions after intramedullary nailing of femoral shaft fractures are a significant problem. Treatment options such as augmenting with plates or exchange nailing have been proposed. The ideal treatment remains controversial., Methods: Augmentative plating using a 4.5 mm LCP or a 3.2 mm LCP leaving the nail in situ was tested biomechanically and compared to exchange intramedullary nailing in a Sawbone TM model of a femoral shaft non-union., Results: The difference of fracture gap motion in axial testing was small. In rotational testing, the exchange nail allowed for the largest amount of motion. The 4.5 mm augmentative plate was the most stable construct in all loading conditions., Conclusions: Augmentative plating using a 4.5 mm LCP plate while leaving the nail in situ is biomechanically superior to exchange intramedullary nailing. A small fragment 3.2 mm LCP is undersized and does not reduce fracture motion sufficiently in a femoral shaft non-union.

Background: Childhood obesity is a pertinent public health problem in the UK. Consumption of free sugars has been associated with the development of obesity. In 2018, the Change 4Life (C4L) 100 cal snack campaign was launched with the slogan '100 calorie snacks, two a day max', aiming to encourage parents to choose lower sugar, fat and calorie snacks for their children. This study aimed to examine how the campaign has been perceived by parents., Methods: An online survey was developed to explore parent awareness, perceptions and understanding of the C4L 100 cal snack campaign. Respondents were recruited via Leeds City Council, posters displayed at primary schools and children's centres across Leeds and via social media. Paper surveys were also shared with voluntarily led playgroups. Survey data was analysed using descriptive statistics. Thematic analysis was performed on open text responses., Results: Three hundred forty-two 342 respondents completed the survey. Just over half of the respondents had come across the campaign, most seeing the leaflet or a television advert. Over two-thirds of respondents 'agreed' or 'strongly agreed' that the campaign caught their attention. A similar proportion 'agreed' or 'strongly agreed' that the campaign informed them about 100 cal snacks and just over a half thought it was memorable. Most respondents used positive language to describe the campaign, but there was no clear consensus of a perceived positive impact on healthier snack purchasing, nor preparing more 100 cal snacks at home. Respondents provided examples of how the campaign could be improved to positively impact eating behaviours: better publicity and information delivery; healthier snack examples made more visible; improved nutritional labelling and access to healthier products in supermarkets (availability, promotion, display, choice)., Conclusions: The C4L 100 cal snack campaign was perceived positively by parents and carers, with many agreeing that the campaign was informative and memorable. However, there was no agreement in terms of the parents reporting an impact of the campaign on behaviour change and healthier snack habits. Future social marketing campaigns could be improved through more formal pilot testing to assess the understanding and acceptance of the campaign amongst the target audience., (© 2022. The Author(s).)

Vitamin D deficiency is a serious public health issue in the United Kingdom. Those at increased risk, such as pregnant women, children under 5 years and people from ethnic groups with dark skin, are not all achieving their recommended vitamin D. Effective vitamin D education is warranted. A qualitative study was undertaken to evaluate the acceptability and understanding of a vitamin D infographic, developed using recommendations from previous research. Fifteen parents/carers, recruited through local playgroups and adverts on popular parent websites, participated in focus groups and telephone interviews. The majority were female, White British and educated to degree level. A thematic analysis methodology was applied. The findings indicated that understanding and acceptability of the infographic were satisfactory, but improvements were recommended to aid interpretation and create more accessible information. These included additional content (what vitamin D is; other sources; its health benefits; methods/doses for administration and scientific symbols used) and improved presentation (eye-catching, less text, simpler language, more images and a logo). Once finalized, the infographic could be a useful tool to educate families around vitamin D supplementation guidelines, support the UK Healthy Start vitamins scheme and help improve vitamin D status for pregnant and lactating women and young children.

Background: Primary schools are valuable settings to implement healthy lifestyle (healthy eating and physical activity) interventions, aimed at targeting childhood obesity. This study explored school staff perceptions of factors that hinder and enable successful implementation and sustainability of healthy lifestyle interventions in primary schools. Qualitative data was pooled and analysed from two evaluations carried out in primary schools in North England: a feasibility study of a nutrition and physical activity educational programme (PhunkyFoods Feasibility Study), and an evaluation of a healthy eating programme (The Food Dudes Evaluation)., Methods: Sixty-five qualitative semi-structured interviews were conducted with head teachers, teachers, catering managers, designated school-based programme coordinators and programme staff supporting schools with programme delivery, at 14 schools involved in both evaluations. Thematic analysis was undertaken and emergent themes categorised using a framework for successful implementation by Durlak and Dupre (2008)., Results: Overall, all schools were delivering a range of healthy lifestyle programmes, often with overlapping content. Perceived challenges to implementation of individual programmes included: limited time, timing of implementation, limited training and support, insufficient resources, capacity and facilities, staff perceptions of intervention and perceived skill-proficiency (for cooking and physical activities). Short-term funding, lack of external and internal support were perceived to hinder sustainability. Staff recommendations for successful implementation of future programmes included: extended training and planning time, sufficient capacity, external support for delivery, good resources (interactive, practical and adaptable), and facilities for cooking, healthy eating, gardening and physical activities. Head teachers need to prioritise delivery of a few key healthy lifestyle programmes, in an overcrowded curriculum. Schools need to employ strategies to engage participation of staff, pupils and parents long term., Conclusions: Effective implementation of school-based healthy lifestyle programmes was thought to be aided by flexible and adaptable programmes, enabling good contextual fit, well-resourced programmes and effective leadership at multiple levels, pupil (pupils support delivery) and parent involvement. To facilitate sustainability, it was perceived that programmes need to be integrated within the curriculum and school policies long term, with sustained support from head teachers and staff. These findings are relevant to programme developers, policy makers and those involved in delivering interventions.

Background: Vitamin D deficiency has been highlighted as a serious public health problem in the United Kingdom. One in four toddlers are not achieving the recommended intake for their healthy development. This study uses quantitative and qualitative methods to explore parents' perceptions, awareness and behaviours around vitamin D intake, and the acceptability of and factors affecting purchasing of food and drink fortified with Vitamin D in children aged 0-2 years old., Methods: One hundred and ninety-four parents completed an online questionnaire, advertised to parents with one child aged up to 2 years on popular social media websites. The majority of participants were mothers, White-British ethnic background, aged 25-44 years. Participants provided an email address if they wanted to be contacted about the focus groups. Recruitment posters advertising the focus groups were placed in community centres. Eighteen participated in 5 focus groups (13 parents), and 5 individual interviews. A thematic analysis methodology was applied., Results: Fifty-seven percent (n = 110) of parents reported receiving information about vitamin D during pregnancy and 52% (n = 100) after the birth of their child. Parents reported a low level of satisfaction with vitamin D information: many thought it was limited and recommendations on supplements were unclear. Parents wanted more information about vitamin D requirements for their child (80%, n = 153 out of 192 respondents, 2 non-response), about vitamin D and breastfeeding (56%, n = 108) and vitamin D and pregnancy (49%, n = 94). The recommendations were for simpler, easier to read, with specific and clearer guidelines; delivered regularly during routine appointments, at timely stages throughout pregnancy and after the birth. 23% (n = 45, out of 194 respondents) of parents did not know why vitamin D is important for health. Only 26% (n = 49, out of 192 respondents) of parents reported giving their youngest child a vitamin D supplement on most days of the week. The majority of parents (interview/focus group) wanted more information about foods/drinks fortified with vitamin D., Conclusion: Parents were generally not aware of the importance of vitamin D, dietary requirements including supplementation and the availability of vitamin D fortified foods. Major improvements are required for the effective promotion of vitamin D information to parents.

The intervertebral disc (IVD) is a highly hydrated tissue, the rich proteoglycan matrix imbibes water, enabling the disc to withstand compressive loads. During aging and degeneration increased matrix degradation leads to dehydration and loss of function. Aquaporins (AQP) are a family of transmembrane channel proteins that selectively allow the passage of water in and out of cells and are responsible for maintaining water homeostasis in many tissues. Here, the expression of all 13 AQPs at gene and protein level was investigated in human and canine nondegenerate and degenerate IVDs to develop an understanding of the role of AQPs during degeneration. Furthermore, in order to explore the transition of notochordal cells (NCs) towards nucleus pulposus (NP) cells, AQP expression was investigated in canine IVDs enriched in NCs to understand the role of AQPs in IVD maturation. AQP0, 1, 2, 3, 4, 5, 6, 7, and 9 were expressed at gene and protein level in both nondegenerate and degenerate human NP tissue. AQP2 and 7 immunopositivity increased with degeneration in human NP tissue, whereas AQP4 expression decreased with degeneration in a similar way to AQP1 and 5 shown previously. All AQP proteins that were identified in human NP tissue were also expressed in canine NP tissue. AQP2, 5, 6, and 9 were found to localize to vacuole-like membranes and cell membranes in NC cells. In conclusion, AQPs were abundantly expressed in human and canine IVDs. The expression of many AQP isotypes potentially alludes to multifaceted functions related to adaption of NP cells to the conditions they encounter within their microenvironment in health and degeneration. The presence of AQPs within the IVD may suggest an adaptive role for these water channels during the development and maintenance of the healthy, mature IVD., Competing Interests: The authors have no conflicts of interest to declare. Author contributionsJ.S., M.C., R.B., M.T. and C.L.M. contributed to study design. R.D. performed some of the RT‐qPCR experiments, F.B. isolated, cultured, and processed canine alginate beads, and prepared canine sections. J.S. performed all other experiments, completed data and statistical analysis, and drafted the manuscript. C.L.M. conceived the study, participated in the design and coordination, aided data analysis, secured funding, and critically revised the manuscript. All authors read and approved the final manuscript.

Mass Spectrometry Imaging (MSI) has evolved into a valuable tool for research into and the diagnosis of disease pathology. The ability to perform multiplex analysis of a wide range of molecules (e.g., proteins, lipids, and metabolites) simultaneously per tissue section while retaining the histological structure of the sample allows molecular information and tissue morphology to be correlated, thus increasing our understanding of a particular disease. Further development of MSI is required to improve suitability to the alternative models available, so that the combined approach can successfully provide the information required in disease characterization and prevention. MSI has been shown to be capable of providing spatiomolecular information in tumor spheroids, living skin equivalents, and ex vivo human tissues. Due to a considerable interest and scientific effort there are many more designed alternative disease models available which would benefit from the information MSI could provide.

Background: Angular stable plate fixation is a widely accepted treatment option for interprosthetic or periprosthetic femoral fractures with stable implants. This biomechanical study tries to establish a safe distance of the plate from the tip of a femoral prosthesis., Methods: A total of 38 composite femurs were reamed to an inner diameter of 23 mm to create an osteoporotic bone model. A Weber hip stem was cemented into each and a distal femoral NCB plate applied with the distance to the stem varying from 8 cm apart to 6 cm overlap in 2-cm steps. Each specimen was tested in cyclic axial loading (400 N-1500 N) and then cyclic torsion (0.6 Nm-50 Nm). Peak strain on the femur around the tip of the plate was measured with a 3D image correlation system and averaged over 26 cycles (excluding the first 3 and the last cycles). Finally, each femur was axially loaded to failure., Results: Strain increased with decreasing overlap or gap. Seven specimens failed early between 2-cm overlap and 2-cm gap. Results were divided into a far group with a distance of >4 cm and a close group of <4 cm. Strain was significantly higher in the close group for axial (P < .001) and torsional (P < .001) loading. Failure load was significantly lower in the close group (P = .002)., Conclusion: A minimal gap and/or overlap of at least 6 cm is recommended in osteoporotic bone to avoid stress risers., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: To investigate the effect of intramedullary pin size and plate working length on plate strain in locking compression plate-rod constructs., Methods: A synthetic bone model with a 40 mm fracture gap was used. Locking compression plates with monocortical locking screws were tested with no pin (LCP-Mono) and intramedullary pins of 20% (LCPR-20), 30% (LCPR-30) and 40% (LCPR-40) of intramedullary diameter. Two screws per fragment modelled a long (8-hole) and short (4-hole) plate working length. Strain responses to axial compression were recorded at six regions of the plate via three-dimensional digital image correlation., Results: The addition of a pin of any size provided a significant decrease in plate strain. For the long working length, LCPR-30 and LCPR-40 had significantly lower strain than the LCPR-20, and plate strain was significantly higher adjacent to the screw closest to the fracture site. For the short working length, there was no significant difference in strain across any LCPR constructs or at any region of the plate. Plate strain was significantly lower for the short working length compared to the long working length for the LCP-Mono and LCPR-20 constructs, but not for the LCPR-30 and LCPR-40 constructs., Clinical Significance: The increase in plate strain encountered with a long working length can be overcome by the use of a pin of 30-40% intramedullary diameter. Where placement of a large diameter pin is not possible, screws should be placed as close to the fracture gap as possible to minimize plate strain and distribute it more evenly over the plate.

Objective: To compare the biomechanical properties of dual bone fixation (DBF) constructs to radial locking compression plating (LCP) in an ex vivo feline antebrachial fracture gap model., Study Design: Ex vivo study., Sample Population: Cadaveric feline antebrachii (n=12 pairs)., Methods: Antebrachii were radiographed to confirm normal skeletal appearance and maturity. After creation of a 5 mm radial and ulnar ostectomy, each antebrachium received 1 of 3 constructs using an incomplete randomized block design (n=8 per group). All groups received a 10 hole 2.0 mm radial LCP. DBF groups received either a 1.2 mm ulnar intramedullary pin (LCP with pin) or an 8 hole 2.0 mm ulnar LCP in addition to the radial LCP. Biomechanical testing was performed in axial compression and caudocranial and mediolateral 4-point bending before destruction in axial compression., Results: DBF constructs (LCP with pin and dual LCP) were significantly stiffer than radial LCP alone in axial compression and caudocranial bending. There were no differences between LCP with pin and dual LCP constructs in axial compression and caudocranial bending or between any constructs in mediolateral bending. Failure load was significantly greater for dual LCP than LCP with pin or LCP alone constructs. Failure loads were not different between LCP with pin and LCP alone., Conclusion: DBF significantly increased construct stiffness and strength. Given the high complication rate reported in cat antebrachial fractures when only the radius is stabilized, surgeons should consider DBF., (© Copyright 2016 by The American College of Veterinary Surgeons.)

The purpose of this study was to mechanically test a novel Unthreaded Expandable Fastener (UEF), manufactured using Selective Laser Melting, which was designed for fixation in the cervical lateral mass. The pull-out strength and stiffness of the prototype UEFs was evaluated in a non-osteoporotic ovine bone model against equivalent screws. The prototype UEF demonstrated a 41% increase in failure force and a 60% reduction in failure force standard deviation compared to the screws. All bone samples were micro CT-scanned and no significant differences in bone microstructural properties was found between the screw and UEF sample sets, indicating that the UEFs may be less sensitive to bone quality variation. This increased performance can potentially translate into improved surgical outcome and reduced surgical risk for lateral mass fixation. With further design optimisation, additional improvement in performance over screws may be possible in future studies.

Background: Aquaporin (AQP) water channels are best known as passive transporters of water that are vital for water homeostasis., Scope of Review: AQP knockout studies in whole animals and cultured cells, along with naturally occurring human mutations suggest that the transport of neutral solutes through AQPs has important physiological roles. Emerging biophysical evidence suggests that AQPs may also facilitate gas (CO2) and cation transport. AQPs may be involved in cell signalling for volume regulation and controlling the subcellular localization of other proteins by forming macromolecular complexes. This review examines the evidence for these diverse functions of AQPs as well their physiological relevance., Major Conclusions: As well as being crucial for water homeostasis, AQPs are involved in physiologically important transport of molecules other than water, regulation of surface expression of other membrane proteins, cell adhesion, and signalling in cell volume regulation., General Significance: Elucidating the full range of functional roles of AQPs beyond the passive conduction of water will improve our understanding of mammalian physiology in health and disease. The functional variety of AQPs makes them an exciting drug target and could provide routes to a range of novel therapies., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Physiotherapy is one of the effective treatments for tendinopathy, whereby symptoms are relieved by changing the biomechanical environment of the pathological tendon. However, the underlying mechanism remains unclear. In this study, we first established a model of progressive tendinopathy-like degeneration in the rabbit Achilles. Following ex vivo loading deprivation culture in a bioreactor system for 6 and 12 days, tendons exhibited progressive degenerative changes, abnormal collagen type III production, increased cell apoptosis, and weakened mechanical properties. When intervention was applied at day 7 for another 6 days by using cyclic tensile mechanical stimulation (6% strain, 0.25 Hz, 8 h/day) in a bioreactor, the pathological changes and mechanical properties were almost restored to levels seen in healthy tendon. Our results indicated that a proper biomechanical environment was able to rescue early-stage pathological changes by increased collagen type I production, decreased collagen degradation and cell apoptosis. The ex vivo model developed in this study allows systematic study on the effect of mechanical stimulation on tendon biology., (© 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

The aim of this study was to biomechanically evaluate the Locking attachment plate (LAP) construct in comparison to a Cable plate construct, for the fixation of periprosthetic femoral fractures after cemented total hip arthroplasty. Each construct incorporated a locking compression plate with bi-cortical locking screws for distal fixation. In the Cable construct, 2 cables and 2 uni-cortical locking screws were used for proximal fixation. In the LAP construct, the cables were replaced by a LAP with 4 bi-cortical locking screws. The LAP construct was significantly stiffer than the cable construct under axial load with a bone gap (P=0.01). The LAP construct offers better axial stiffness compared to the cable construct in the fixation of comminuted Vancouver B1 proximal femoral fractures., (Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.)

Despite recent attempts to improve the quality of school meals in England through the introduction of school meal standards, uptake remains low. Since the introduction of the universal infant free school meal (UIFSM) scheme in September 2014 all pupils in Reception, Year 1 and Year 2 in English state-funded primary schools are eligible to receive a free lunch. This study aimed to explore the perceptions of pupils, catering managers and head teachers concerning school meal provision in eight primary schools in North England and provides a unique insight into each school's preparation for implementation of UIFSM. A total of thirty-two focus groups were conducted with sixty-four pupils aged 7-8 years (Year 3) and sixty-four pupils aged 9-10 years (Year 5) in June-July 2014, to explore perceptions of school meals. Interviews were carried out with six catering managers and five head teachers concerning catering and the impending implementation of UIFSM. Increasing acceptance of school meals could lead to improved uptake. Pupils desired increased choice and menu variety, including greater variety of vegetables and fruit. Caterers can influence the quantity and types of foods offered to pupils, and there are opportunities for them to promote healthy eating behaviours in the dining room. The important roles of school meal providers, caterers, pupils and parents need to be recognised to improve delivery and acceptability of school meals and ultimately school meal uptake. There were practical challenges to implementation of UIFSM, with some concerns expressed over its feasibility. Head teachers were mainly positive about the potential beneficial impacts of the scheme.

The aquaporin family of integral membrane proteins is composed of channels that mediate cellular water flow. Aquaporin 4 (AQP4) is highly expressed in the glial cells of the central nervous system and facilitates the osmotically driven pathological brain swelling associated with stroke and traumatic brain injury. Here we show that AQP4 cell surface expression can be rapidly and reversibly regulated in response to changes of tonicity in primary cortical rat astrocytes and in transfected HEK293 cells. The translocation mechanism involves PKA activation, influx of extracellular calcium, and activation of calmodulin. We identify five putative PKA phosphorylation sites and use site-directed mutagenesis to show that only phosphorylation at one of these sites, serine 276, is necessary for the translocation response. We discuss our findings in the context of the identification of new therapeutic approaches to treating brain edema., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Objective: To compare the biomechanical properties of a 10-hole 3.5 mm locking compression plate (LCP) with 2 proximal and 2 distal bicortical locked screws reinforced with either a Steinmann pin of 30-40% the medullary diameter or a poly-ether-ether-ketone (PEEK) rod of ∼75% the medullary diameter in a cadaveric tibia gap model., Study Design: Ex vivo study., Sample Population: Cadaveric canine tibias (n = 8 pair)., Methods: Each construct had a 10-hole 3.5 mm LCP with 2 screws per fracture fragment using a comminuted tibia gap model. The Steinmann pin constructs had a 2.4 mm intramedullary pin whereas the PEEK-rod constructs had a 6 mm intramedullary PEEK rod placed. Biomechanical testing included non-destructive bi-planar 4 point bending, torsion testing, and destructive axial compression. Testing produced the responses of failure load (N) in axial compression, stiffness (N/mm or N/°) in axial compression, torsion, lateral-medial, and caudal-cranial 4 point bending. Screw position within the PEEK-rods was determined after explantation., Results: The PEEK-rod constructs were significantly stiffer in axial compression (P < .005), lateral-medial 4 point bending (P < .001), and in torsional loading (P < .031) than the Steinman pin constructs. There was no significant difference between the constructs for stiffness in caudal-cranial 4 point bending (P = .32). The PEEK-rod constructs failed at a significantly higher load than the Steinmann pin constructs (P < .001). All constructs failed by yielding through plastic deformation. Each screw penetrated the PEEK rod in all constructs but the position of the screw varied., Conclusion: PEEK-rod constructs failed at significantly higher loads and were significantly stiffer in 4 point lateral-medial bending, axial compression, and torsion when compared with Steinmann pin constructs., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Periprosthetic femoral fractures (PFF) are a serious complication after total hip arthroplasty. Plate fixation with screws perforating the cement mantle is a common treatment option. The study objective was to investigate hip stem stability and cement mantle integrity under dynamic loading. A cemented hip stem was implanted in 17 composite femur models. Nine bone models were osteotomised just distal to the stem and fixed with a polyaxial locking plate the other eight constructs served as the control group. All specimens were tested in a bi-axial material testing machine (100000 cycles). There were no statistically significant differences in axial nor in medial (varus) stem migration. No cement cracks were detected in both groups. Plate fixation of a PFF with a stable, cemented prosthesis did not lead to cement mantle failure in this in vitro study., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Emerging evidence supports the view that (AQP) aquaporin water channels are regulators of transcellular water flow. Consistent with their expression in most tissues, AQPs are associated with diverse physiological and pathophysiological processes., Scope of Review: AQP knockout studies suggest that the regulatory role of AQPs, rather than their action as passive channels, is their critical function. Transport through all AQPs occurs by a common passive mechanism, but their regulation and cellular distribution varies significantly depending on cell and tissue type; the role of AQPs in cell volume regulation (CVR) is particularly notable. This review examines the regulatory role of AQPs in transcellular water flow, especially in CVR. We focus on key systems of the human body, encompassing processes as diverse as urine concentration in the kidney to clearance of brain oedema., Major Conclusions: AQPs are crucial for the regulation of water homeostasis, providing selective pores for the rapid movement of water across diverse cell membranes and playing regulatory roles in CVR. Gating mechanisms have been proposed for human AQPs, but have only been reported for plant and microbial AQPs. Consequently, it is likely that the distribution and abundance of AQPs in a particular membrane is the determinant of membrane water permeability and a regulator of transcellular water flow., General Significance: Elucidating the mechanisms that regulate transcellular water flow will improve our understanding of the human body in health and disease. The central role of specific AQPs in regulating water homeostasis will provide routes to a range of novel therapies. This article is part of a Special Issue entitled Aquaporins., (© 2013. Published by Elsevier B.V. All rights reserved.)

Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

Identification of functional programmable mechanical stimulation (PMS) on tendon not only provides the insight of the tendon homeostasis under physical/pathological condition, but also guides a better engineering strategy for tendon regeneration. The aims of the study are to design a bioreactor system with PMS to mimic the in vivo loading conditions, and to define the impact of different cyclic tensile strain on tendon. Rabbit Achilles tendons were loaded in the bioreactor with/without cyclic tensile loading (0.25 Hz for 8 h/day, 0-9% for 6 days). Tendons without loading lost its structure integrity as evidenced by disorientated collagen fiber, increased type III collagen expression, and increased cell apoptosis. Tendons with 3% of cyclic tensile loading had moderate matrix deterioration and elevated expression levels of MMP-1, 3, and 12, whilst exceeded loading regime of 9% caused massive rupture of collagen bundle. However, 6% of cyclic tensile strain was able to maintain the structural integrity and cellular function. Our data indicated that an optimal PMS is required to maintain the tendon homeostasis and there is only a narrow range of tensile strain that can induce the anabolic action. The clinical impact of this study is that optimized eccentric training program is needed to achieve maximum beneficial effects on chronic tendinopathy management., (Copyright © 2012 Wiley Periodicals, Inc.)

This study proposes a method for measuring the refractive index of articular cartilage within a thin and small specimen slice. The cartilage specimen, with a thickness of about 50 μm, was put next to a thin film of immersion oil of similar thickness. Both the articular cartilage and immersion oil were scanned along the depth direction using a confocal microscope. The refractive index mismatch between the cartilage and the immersion oil induced a slight axial deformation in the confocal images of the cartilage specimen that was accurately measured by a subpixel edge-detection-based technique. A theoretical model was built to quantify the focal shift of confocal microscopy caused by the refractive index mismatch. With the quantitative deformations of cartilage images and the quantified function of focal shift, the refractive index of articular cartilage was accurately interpolated. At 561 nm, 0.1 MPa and 20 °C, the overall refractive index of the six cartilage plugs was 1.3975 ± 0.0156. The overall coefficient of variation of all cartilage specimens was 0.68%, which indicated the high repeatability of our method. The verification experiments using distilled water showed a minimal relative error of 0.02%., (© 2012 The Authors Journal of Microscopy © 2012 Royal Microscopical Society.)

Custom titanium cranioplasty plates, manufactured by a variety of techniques, have been used to repair a range of cranial defects. The authors present a case where two relatively large, adjacent cranial defects were repaired by custom computer-designed titanium plates. The two plates were designed and fabricated simultaneously using a unique methodology. A 28-year-old woman underwent a corpus callosotomy for medically intractable epilepsy. The surgery was complicated by unexpected haemorrhage which necessitated a second craniotomy. Subsequent deep infection required the removal of bilateral bone flaps, presenting a challenge in the reconstruction of extensive, bilateral but asymmetrical cranial defects. The patient underwent a head computed tomography scan, from which a rapid-prototype model of the skull was produced. The surfaces for the missing cranial segments were generated virtually using a combination of software products and two titanium plates that followed these virtual contours were manufactured to cover the defects. The cranioplasty procedure to implant both titanium cranial plates was performed efficiently with no intra-operative complications. Intra-operatively, an excellent fit was achieved. The careful planning of the plates enhanced the relative ease with which the cranial defects were repaired with an excellent cosmetic outcome.

Background: The pathogenesis of glucocorticoid-induced osteoporosis remains ill defined. In this study, we examined the role of the osteoblast in mediating the effects of exogenous glucocorticoids on cortical and trabecular bone, employing the Col2.3-11βHSD2 transgenic mouse model of osteoblast-targeted disruption of glucocorticoid signalling., Methods: Eight week-old male transgenic (tg) and wild-type (WT) mice (n=20-23/group) were treated with either 1.5 mg corticosterone (CS) or placebo for 4 weeks. Serum tartrate-resistant acid phosphatase 5b (TRAP5b) and osteocalcin (OCN) were measured throughout the study. Tibiae and lumbar vertebrae were analysed by micro-CT and histomorphometry at endpoint., Results: CS suppressed serum OCN levels in WT and tg mice, although they remained higher in tg animals at all time points (p<0.05). Serum TRAP5b levels increased in WT mice only. The effect of CS on cortical bone differed by site: At the endosteal surface, exposure to CS significantly increased bone resorption and reduced bone formation, resulting in a larger bone marrow cavity cross-sectional area (p<0.01). In contrast, at the pericortical surface bone resorption was significantly decreased accompanied with a significant increase in pericortical cross-sectional area (p<0.05) while bone formation remained unaffected. Vertebral cortical thickness and area were reduced in CS treatment mice. Tg mice were partially protected from the effects of exogenous CS, both on a cellular and structural level. At the CS doses used in this study, trabecular bone remained largely unaffected., Conclusion: Endocortical osteoblasts appear to be particularly sensitive to the detrimental actions of exogenous glucocorticoids. The increase in tibial pericortical cross-sectional area and the according changes in pericortical circumference suggest an anabolic bone response to GC treatment at this site. The protection of tg mice from these effects indicates that both catabolic and anabolic action of glucocorticoids are, at least in part, mediated by osteoblasts., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: To test single cycle to failure tensile strength characteristics of 6 suture material-pattern combinations in equine superficial digital flexor (SDF) tenorrhaphy, specifically to compare a 10-strand modification of the Savage core suture technique with the 3-loop pulley technique., Study Design: Ex vivo mechanical experiment comparing 3 different suture patterns with 2 different materials., Sample Population: Forelimb and hindlimb SDF tendons (n=48) harvested from adult Thoroughbred and Standardbred horses of mixed age and gender., Methods: Six suture material-pattern combinations were evaluated: (1) 10-strand Savage, size 2 polydioxanone (PDS); (2) 10-strand Savage, size 2 polyglactin 910 (PG910); (3) 10-strand Savage, size 2 PDS with Lin-locking epitenon suture, size 2-0 PDS; (4) 10-strand Savage size 2 PG910 with Lin-locking epitenon suture, size 2-0 PDS; (5) 3-loop pulley, size 2 PDS; and (6) 3-loop pulley, size 2 PG910. Maximum load at failure (N), gap at failure (mm), and mode of failure (suture breakage or pull through) were evaluated for each of the 6 suture material-pattern combinations and underwent statistical analysis to determine significance of differences and interactions of the measured data., Results: The 10-strand Savage technique failed at a mean load of 872 (804-939, 95% CI). The 10-strand Savage with Lin-locking failed at a significantly greater mean load of 998 (930-1065, 95% CI). The 3-loop pulley pattern failed with a mean load of 337 (270-405, 95% CI). There were significant interactions between the technique and suture material used., Conclusion: The 10-strand Savage technique for repair of transected cadaver SDF tendons has superior strength characteristics with or without the epitenon suture when compared to the 3-loop pulley. Suture material and pattern interactions were observed with PG 910 conferring higher strength for the 10-strand Savage whereas PDS did so for the 3-loop pulley., (© Copyright 2011 by The American College of Veterinary Surgeons.)

Background: The optimal plate location and fixation method for midshaft fractures of the clavicle remains undetermined. The objective of this study was to develop a realistic biomechanical model with which to compare superior with inferior-medial plate placement, and the failure resistance of locked and against non-locked constructs., Methods: We estimated implant loads for operated patients in early rehabilitation utilising 3-D mathematical model of the shoulder. During simulation of upper limb motion associated with eating, the fracture opened in an inferior and frontal direction. The peak X, Y, and Z loads from the simulation were reproduced using a materials testing machine. A one centimetre transverse osteectomy was created at the midshaft of forty composite clavicles. Each specimen was then fixed with either (1) non-locked superior plating (n=10), (2) locked superior plating (n=10), (3) non-locked inferior-medial plating (n=10), or (4) locked inferior-medial plating (n=10). Specimens were loaded at 20 N/s in four-point bending for 50 cycles to the peak X, Y, Z moment obtained from the computational model (-3.50, 2.46, and -1.00 N m), then loaded to failure at 20 N/s., Findings: Inferior-medial unlocked plates were significantly stiffer than superior locked plates (P=0.046)., Interpretation: Operative fixation of midshaft clavicle fractures is controversial, though becoming more widely accepted. Few biomechanical data are available to assist surgical decision-making. Inferior plates may be better equipped to resist the in vivo loads experienced by the clavicle during early rehabilitation after internal fixation, particularly during the shoulder flexion motions associated with eating., (Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.)

Objective: To determine (1) the minimum number of throws to form secure Aberdeen (AB) and square knots to start (SS) and end (SE) continuous patterns, in fat- and plasma-coated polydioxanone; and (2) compare relative knot security (RKS) and knot volumes of these secure SS, SE, and AB knots., Study Design: In vitro experimental materials testing., Sample Population: Polydioxanone suture material (3 metric)., Methods: Each knot was tested 20 times, and throws incrementally added until secure SS, SE, and AB knots were found. RKS and knot volumes were calculated for SS, SE, and AB knots., Results: Secure SE knots needed 5 throws in plasma or fat. Secure SS knots needed 4 throws in plasma, but 5 in fat. The minimum AB configuration that was secure in plasma or fat was 3+1, however, the 4+1 AB knot was also secure in fat. Mean (SD) RKS of secure knots were: SE 59.69% (5.91), SS 67.92% (12.50), AB 81.08% (8.99). AB knots had significantly higher mean RKS than any SS or SE knot in plasma or fat (P<.001). Mean knot volume of 3+1 AB knot was significantly smaller than any secure SS or SE knots by 22.6-69.4% (P<.0001). Mean knot volume of 4+1 AB knots was significantly smaller than all fat secure SS and SE knots by 19.9-57.5% (P=.0001)., Conclusion: The knot security of the SS knot was decreased by fat coating polydioxanone suture, requiring an additional throw to keep it secure. Secure AB knots had a higher breaking strength and smaller knot volume than secure SS and SE knots., Clinical Relevance: The AB may be preferable to square knots in continuous closures. As many body fluids contain lipid, surgeons should tie knot configurations considered secure in fat. We advise tying a 4+1 AB and placing a minimum of 5 throws to tie SS and SE knots using 3 metric polydioxanone.

Objectives: To determine the minimum number of throws/turns to form a secure Aberdeen knot and the maximum ear slippage for these knots using three metric polydioxanone coated in fat or plasma. To compare plasma and novel canine liquefied fat as suture coating mediums for in vitro knot security testing., Methods: Throws/turns were incrementally added until a secure knot was found for plasma and fat. Knots were tensioned until failure and remaining ear length measured. A secure knot was defined as ear slippage 3 mm or less in 20 consecutively tested knots. Ear slippages were statistically analysed., Results: Minimum secure configuration was a 3+1 knot in plasma and fat, and its ear slipped a maximum of 2 mm in plasma and 2.5 mm in fat. A secure 4+1 knot had a maximum ear slippage of 0.5 mm, which was significantly less than that of the 3+1 knot (P<0.0001). Fat coating suture significantly decreases in vitro knot security compared with plasma (P=0.0035)., Clinical Significance: The novel fat coating medium should be considered when testing in vitro knot security as it simulates a clinical knot tying environment. A 4+1 Aberdeen knot with a 3 mm ear is recommended to tie a secure Aberdeen knot in any body fluid environment.

The role of endogenous glucocorticosteroids (GC) in bone development is ill-defined. Using the Col2.3-11betaHSD2 transgenic (tg) mouse model, we examined the effect of osteoblast-targeted disruption of intracellular GC signalling on bone growth and strength, and its modulation by factors such as age, gender and skeletal site. Tibiae and L3 vertebrae of 3 and 7-week-old, male and female wild type (WT) mice and their tg, age and sex matched littermates were analysed by micro-CT and mechanical testing. Data were analysed separately for 3 and 7-week-old mice by 2-way ANOVA using genotype (WT, tg), gender and their interactions as factors. Transgenic mice were characterised by lower bone volume, lower trabecular number and higher trabecular separation in tibial trabecular bone, as well as lower tibial cortical bone area and periosteal and endosteal perimeters. These changes resulted in a marked decrease in mechanical bone strength and stiffness in sexually mature, 7-week-old mice. In the tibia, the observed transgene effect was present in 3 and 7-week-old animals, indicating that the biological effect of disrupted GC signalling was independent of sexual maturity. This was not the case for the vertebral bones, where significant differences between tg and WT mice were seen in 7 but not in 3-week-old animals, suggesting that the effects of the transgene at this site may be modulated by age and/or changes in circulating sex hormone levels. Taken together, our results demonstrate that endogenous glucocorticoids may be required for normal bone growth but that their effect on bone structure and strength varies according to the skeletal site and sexual maturity of the animals.

The healthcare cost of managing osteoporotic fractures is projected to rise because of the change in population demographics. To reduce the fracture epidemic, strategies are needed to identify those at risk early to allow preventative intervention to be implemented. The aim of this study was to investigate if low-cost community-based assessments, such as calcaneal ultrasound and falls risk assessments, can discriminate a group of elderly women at risk of osteoporotic fracture from those at lower risk. Over the period of 2002-2003, 104 community-dwelling women (mean age 71.3, standard deviation 5.8) were recruited via various modes including advertisements in community newspaper and community centres. These women underwent dual-energy X-ray absorptiometry bone mineral density (BMD) and calcaneal quantitative ultrasound (QUS) measurements; spinal radiography; and performance-based assessment of strength, mobility and balance. The women were classified into a 'high risk' (osteoporotic) group, based on low BMD (T-score of

Children with neurological impairments often have visual deficits that are difficult to quantify. We have compared visual skills evaluated by carers with results of a comprehensive visual assessment. Participants were 76 children with mild to profound intellectual and/or motor impairment (33 males, 43 females; age range 7mo-16y; mean age 5y 1mo [SD 4y 2mo]) who completed a visual skills inventory before attending a special vision clinic. The inventory included 16 questions about visual skills and responses to familiar situations. Responses were augmented by taking a structured clinical history, compared with visual evoked potential (VEP) and/or acuity card measures of visual acuity, and examined using exploratory factor analysis. Acuity ranged from normal to no light perception, and was positively associated with responses to individual questions. After excluding four uninformative questions, an association between the remaining questions and two significant independent factors was found. Factor 1 was associated with questions about visual recognition (e.g. 'Does your child see a small silent toy?') and these items were correlated with both the VEP and acuity card thresholds. Factor 2 was associated primarily with questions about visually mediated social interactions (e.g. 'Does he/she return your silent smile?'). Evaluation of visual skills in children with neurological impairment can provide valid information about the quality of children's vision. Questions with the highest validity for predicting vision are identified.

Revision arthroplasty after infection can often be complicated by both extensive bone loss and a relatively high rate of re-infection. Using allograft to address the bone loss in such patients is controversial because of the perceived risk of bacterial infection from the use of avascular graft material. We describe 12 two-stage revisions for infection in which segmental allografts were loaded with antibiotics using iontophoresis, a technique using an electrical potential to drive ionised antibiotics into cortical bone. Iontophoresis produced high levels of antibiotic in the allograft, which eluted into the surrounding tissues. We postulate that this offers protection from infection in the high-risk peri-operative period. None of the 12 patients who had two-stage revision with iontophoresed allografts had further infection after a mean period of 47 months (14 to 78).

Iontophoresis is a novel technique which may be used to facilitate the movement of antibiotics into the substance of bone using an electrical potential applied externally. We have examined the rate of early infection in allografts following application of this technique in clinical practice. A total of 31 patients undergoing revision arthroplasty or surgery for limb salvage received 34 iontophoresed sequential allografts, of which 26 survived for a minimum of two years. The mean serum antibiotic levels after operation were low (gentamicin 0.37 mg/l (0.2 to 0.5); flucloxacillin 1 mg/l (0 to 1) and the levels in the drains were high (gentamicin 40 mg/l (2.5 to 131); flucloxacillin 17 mg/l (1 to 43). There were no early deep infections. Two late infections were presumed to be haemotogenous; 28 of the 34 allografts were retained. In 12 patients with pre-existing proven infection further infection has not occurred at a mean follow-up of 51 months (24 to 82).

Our aim was to assess the intra- and inter-observer reliability in the establishment of the anterior pelvic plane used in imageless computer-assisted navigation. From this we determined the subsequent effects on version and inclination of the acetabular component. A cadaver model was developed with a specifically-designed rod which held the component tracker at a fixed orientation to the pelvis, leaving the anterior pelvic plane as the only variable. Eight surgeons determined the anterior pelvic plane by palpating and registering the bony landmarks as reference points. The exact anterior pelvic plane was then established by using anatomically-placed bone screws as reference points. The difference between the surgeons was found to be highly significant (p < 0.001). The variation was significantly larger for anteversion (sd 9.6 degrees ) than for inclination (sd 6.3 degrees ). The present method for registering pelvic landmarks shows significant inaccuracy, which highlights the need for improved methods of registration before this technique is considered to be safe.

Allograft bone is widely used in orthopaedic surgery, but peri-operative infection of the graft remains a common and disastrous complication. The efficacy of systemic prophylactic antibiotics is unproven, and since the graft is avascular it is likely that levels of antibiotic in the graft are low. Using an electrical potential to accelerate diffusion of antibiotics into allograft bone, high levels were achieved in specimens of both sheep and human allograft. In human bone these ranged from 187.1 mg/kg in endosteal (sd 15.7) to 124.6 (sd 46.2) in periosteal bone for gentamicin and 31.9 (sd 8.9) in endosteal and 2.9 (sd 1.1) in periosteal bone for flucloxacillin. The antibiotics remained active against bacteria in vitro after iontophoresis and continued to elute from the allograft for up to two weeks. Structural allograft can be supplemented directly with antibiotics using iontophoresis. The technique is simple and inexpensive and offers a potential means of reducing the rate of peri-operative infection in allograft surgery. Iontophoresis into allograft bone may also be applicable to other therapeutic compounds.

Efficient fermentation of maltotriose is a desired property of Saccharomyces cerevisiae for brewing. In a standard wort, maltotriose is the second most abundant sugar, and slower uptake leads to residual maltotriose in the finished product. The limiting factor of sugar metabolism is its transport, and there are conflicting reports on whether a specific maltotriose permease exists or whether the mechanisms responsible for maltose uptake also carry out maltotriose transport. In this study, radiolabeled maltotriose was used to show that overexpression of the maltose permease gene, MAL61, in an industrial yeast strain resulted in an increase in the rate of transport of maltotriose as well as maltose. A strain derived from W303-1A and lacking any maltose or maltotriose transporter but carrying a functional maltose transport activator (MAL63) was developed. By complementing this strain with permeases encoded by MAL31, MAL61, and AGT1, it was possible to measure their specific transport kinetics by using maltotriose and maltose. All three permeases were capable of high-affinity transport of maltotriose and of allowing growth of the strain on the sugar. Maltotriose utilization from the permease encoded by AGT1 was regulated by the same genetic mechanisms as those involving the maltose transcriptional activator. Competition studies carried out with two industrial strains, one not containing any homologue of AGT1, showed that maltose uptake and maltotriose uptake were competitive and that maltose was the preferred substrate. These results indicate that the presence of residual maltotriose in beer is not due to a genetic or physiological inability of yeast cells to utilize the sugar but rather to the lower affinity for maltotriose uptake in conjunction with deteriorating conditions present at the later stages of fermentation. Here we identify molecular mechanisms regulating the uptake of maltotriose and determine the role of each of the transporter genes in the cells.