Biomechanical comparison of bone staple fixation methods with suture material for median sternotomy closure using 3D-printed bone models

AIM

To compare the biomechanical properties of three different sternal closure techniques in a 3D-printed bone model of a sternum from a 30-kg dog.

METHODS

Median sternotomy was performed on a total of 90 three-dimensional (3D) copies of a polycarbonate (PC) model of a sternum, generated from the CT images of the sternum of a 30-kg German Shepherd dog. Three different methods were used to repair the sternotomies: polydioxanone suture (group PDS, n = 30), stainless steel bone staples (group SS, n = 30), and nitinol bone staples (group NS, n = 30). Each repair method was tested by applying tensile force in one of three ways (longitudinally, laterally, or torsionally) resulting in a sample size of n = 10 for each repair method-loading combination. In all experiments, the loads at 1-mm and 2-mm gap formation, failure, and the displacement at the failure point were measured.

RESULTS

In lateral distraction and longitudinal shear tests, NS and SS staple repairs required application of significantly greater force than PDS across all displacement criteria (1 and 2 mm). NS exhibited significantly greater failure load than PDS. In torsion tests, NS required significantly greater application of force compared to SS or PDS at all displacement criteria (1 and 2 mm) and exhibited a greater failure load than PDS. In terms of displacement at failure point, PDS suture showed more displacement than SS or NS across all experiments (laterally, longitudinally, torsionally).

CONCLUSIONS

In this study, bone staples were mechanically superior to PDS suture in median sternotomy closure using 3D-printed bone model in terms of 1-mm, 2-mm displacement loads, and displacement at failure. NS had a higher failure load than PDS under lateral, longitudinal, and torsional distraction.

CLINICAL RELEVANCE

These study results imply that bone staples can be considered as an alternative surgical method for median sternotomy closure in dogs.

Survey of awareness and attitudes to the management of fragility fractures among the membership of the Asia Pacific Orthopaedic Association

A survey of awareness and attitudes to the management of fragility fractures among the membership of the Asia Pacific Orthopaedic Association conducted in 2022 found considerable variation in care across the region. A Call to Action is proposed to improve acute care, rehabilitation and secondary fracture prevention across Asia Pacific.

PURPOSE

Fragility fractures impose a substantial burden on older people and their families, healthcare systems and national economies. The current incidence of hip and other fragility fractures across the Asia Pacific region is enormous and set to escalate rapidly in the coming decades. This publication describes findings of a survey of awareness and attitudes to the management of fragility fractures among the membership of the Asia Pacific Orthopaedic Association (APOA) conducted in 2022.

METHODS

The survey was developed as a collaboration between the Asia Pacific Osteoporosis and Fragility Fracture Society and the Asia Pacific Fragility Fracture Alliance, and included questions relating to aspects of care upon presentation, during surgery and mobilisation, secondary fracture prevention, and access to specific services.

RESULTS

In total, 521 APOA members completed the survey and marked variation in delivery of care was evident. Notable findings included: Fifty-nine percent of respondents indicated that analgesia was routinely initiated in transit (by paramedics) or within 30 minutes of arrival in the Emergency Department. One-quarter of respondents stated that more than 80% of their patients underwent surgery within 48 hours of admission. One-third of respondents considered non-hip, non-vertebral fractures to merit assessment of future fracture risk. One-third of respondents reported the presence of an Orthogeriatric Service in their hospital, and less than a quarter reported the presence of a Fracture Liaison Service.

CONCLUSION

A Call to Action for all National Orthopaedic Associations affiliated with APOA is proposed to improve the care of fragility fracture patients across the region.

Fracture Liaison Service and Its Role in Secondary Fracture Prevention in Malaysia: A Scoping Review

Introduction

Fragility fractures, which occur after a low-trauma injury, increases with advancing age. Such fracture doubles the life-time risk of sustaining another fracture. This risk is highest in the immediate 18 months after the index fracture. However, most patients do not receive the appropriate risk assessment and intervention to reduce this risk. A coordinated model of care termed Fracture Liaison Service (FLS) has been reported to address this treatment gap.

Materials and methods

This scoping review aims to explore the potential role and delivery of FLS services in Malaysia. Scientific and non-scientific sources relevant to FLS were identified from electronic bibliographic databases, specialist journals and relevant websites. Findings were categorised into themes and presented narratively.

Results

FLS services remain concentrated in the Klang Valley. Even within FLS services, many do not have extensive coverage to risk assess all fracture patients. These services are multidisciplinary in nature where there are links between different departments, such as orthopaedics, osteoporosis expertise, bone densitometry, rehabilitation, falls services and primary care. FLS was able to increase the number of people undergoing fracture risk assessment and treatment. The importance of FLS was highlighted by local experts and stakeholders. Its implementation and delivery are supported by a number of national guidelines.

Conclusion

FLS is central to our national efforts to reduce the impending fragility fracture crisis in the coming years. Continued effort is needed to increase coverage within FLS services and across the country. Training, awareness of the problem, research, and policy change will support this endeavour.

A summary of the Malaysian Clinical Practice Guidelines on the management of postmenopausal osteoporosis, 2022

Objectives

The aim of these Clinical Practice Guidelines is to provide evidence-based recommendations to assist healthcare providers in the screening, diagnosis and management of patients with postmenopausal osteoporosis (OP).

Methods

A list of key clinical questions on the assessment, diagnosis and treatment of OP was formulated. A literature search using the PubMed, Medline, Cochrane Databases of Systematic Reviews, and OVID electronic databases identified all relevant articles on OP based on the key clinical questions, from 2014 onwards, to update from the 2015 edition. The articles were graded using the SIGN50 format. For each statement, studies with the highest level of evidence were used to frame the recommendation.

Results

This article summarizes the diagnostic and treatment pathways for postmenopausal OP. Risk stratification of patients with OP encompasses clinical risk factors, bone mineral density measurements and FRAX risk estimates. Non-pharmacological measures including adequate calcium and vitamin D, regular exercise and falls prevention are recommended. Pharmacological measures depend on patients' fracture risk status. Very high-risk individuals are recommended for treatment with an anabolic agent, if available, followed by an anti-resorptive agent. Alternatively, parenteral anti-resorptive agents can be used. High-risk individuals should be treated with anti-resorptive agents. In low-risk individuals, menopausal hormone replacement or selective estrogen receptor modulators can be used, if indicated. Patients should be assessed regularly to monitor treatment response and treatment adjusted, as appropriate.

Conclusions

The pathways for the management of postmenopausal OP in Malaysia have been updated. Incorporation of fracture risk stratification can guide appropriate treatment.

Quality improvement initiatives in the care and prevention of fragility fractures in the Asia Pacific region

This narrative review summarises ongoing challenges and progress in the care and prevention of fragility fractures across the Asia Pacific region since mid-2019. The approaches taken could inform development of national bone health improvement Road Maps to be implemented at scale during the United Nations 'Decade of Healthy Ageing'.

PURPOSE

This narrative review summarises recent studies that characterise the burden of fragility fractures, current care gaps and quality improvement initiatives intended to improve the care and prevention of fragility fractures across the Asia Pacific region.

METHODS

The review focuses on published studies, reports and quality improvement initiatives undertaken during the period July 2019 to May 2022.

RESULTS

Epidemiological studies conducted in countries and regions throughout Asia Pacific highlight the current and projected increasing burden of fragility fractures. Recent studies and reports document a persistent and pervasive post-fracture care gap among people who have sustained fragility fractures. Global initiatives developed by the Fragility Fracture Network and International Osteoporosis Foundation have gained significant momentum in the Asia Pacific region, despite the disruption caused by the COVID-pandemic. The Asia Pacific Fragility Fracture Alliance has developed educational resources including a Hip Fracture Registry Toolbox and a Primary Care Physician Education Toolkit. The Asia Pacific Osteoporosis and Fragility Fractures Society-a new section of the Asia Pacific Orthopaedic Association-is working to engage orthopaedic surgeons across the region in the care and prevention of fragility fractures. The Asia Pacific Consortium on Osteoporosis developed a framework to support national clinical guidelines development groups. Considerable activity at the national level is evident in many countries across the region.

CONCLUSION

Development and implementation of national Road Maps informed by the findings of this review are urgently required to respond to the epidemiological emergency posed by fragility fractures during the United Nations 'Decade of Healthy Ageing'.

Recovery from Cranial Nerve Symptoms after Flow Diversion without Coiling for Unruptured Very Large and Giant ICA Aneurysms

BACKGROUND AND PURPOSE

Cranial nerve symptoms, including visual impairment and ophthalmoplegia, are one of the most common presentations of very large and giant (≥15 mm) ICA aneurysms. In this study, we evaluated the treatment outcomes of flow diversion and conventional coiling in terms of recovery from cranial nerve symptoms and postoperative complications.

MATERIALS AND METHODS

Seventy-nine patients with unruptured ICA aneurysms of >15 mm who were treated with flow diversion or conventional coiling between December 2009 and December 2020 were retrospectively evaluated. We compared the radiologic and clinical outcomes, including recovery from cranial nerve symptoms, between the 2 groups.

RESULTS

Twenty-eight of 49 patients (57.1%) treated with flow diversion and 10 of 30 patients (33.3%) treated with conventional coiling initially presented with cranial nerve symptoms (P = .068). In the clinical follow-up, the symptom recovery rate was significantly higher in those treated with flow diversion (15 [50%] versus 3 [25%] with conventional coiling, P = .046). Multivariate logistic regression analysis demonstrated that flow diversion was significantly associated with symptom recovery (OR, 7.425; 95% CI, 1.091-50.546; P = .040). The overall postoperative complication rate was similar (flow diversion, 10 [20.4%]; conventional coiling, 6 [20.0%], P = .965), though fatal hemorrhagic complications occurred only in patients with intradurally located aneurysms treated with flow diversion (4 [8.2%] versus 0 [0.0%] with coiling, P = .108).

CONCLUSIONS

Flow diversion without coiling for very large and giant ICA aneurysms yielded a higher rate of recovery from cranial nerve symptoms, but it may be related to an increased hemorrhagic complication rate, especially for intradurally located aneurysms.

Immunoglobulin D Multiple Myeloma with a “Hidden” Lambda Light Chain

Introduction/Objective

In rare cases, the conventional immunofixation gel electrophoresis technique fails to detect the light chain of an M-protein. We report a case of immunoglobulin (Ig) D multiple myeloma with a hidden lambda (λ) light chain.

Methods/Case Report

Capillary electrophoresis (CE) (Sebia CAPILLARYS 2) was used to detect and quantify M- proteins in serum specimens. Immunosubtraction (IS) on the CAPILLARYS 2 systems was used to identify the classes of M-proteins. Conventional gel immunofixation electrophoresis (IFE) was performed, using monospecific antisera for IgD, IgE, kappa (κ) or λ in the Sebia HYDRASYS system, and IgG, IgA, IgM, κ or λ in the Helena SPIFE3000 system. Beta-mercaptoethanol (BME) with Fluidil were used as reduction agents.

Results (if a Case Study enter NA)

Results of serum CE showed two abnormal peaks in beta 2 and gamma regions, suspected to be positive for M-proteins. IS results showed subtraction for λ light chain only in both peaks, suggesting two monoclonal λ light chains. In contrary, no monoclonal λ light chain was detected in gamma region by IFE (Sebia). Epitope masking in the folded monoclonal protein was suspected to cause the “hidden λ light chain” and was further investigated by two laboratory approaches. IFE performed on the Helena SPIFE3000 system found two λ bands in beta 2 and gamma regions, which was consistent with the results from IS. The treatment of BME with Fluidil helped unmasking the hidden epitope and revealed the λ band in gamma region on IFE (Sebia).

Conclusion

The medical laboratories should be aware of the described scenario. The failure to detect light chains of certain intact M-proteins is most likely due to the structurally inaccessibility of light chains. It is recommended that treatment with reduction agents or use of an alternative methodology or IS might be helpful for investigating suspected heavy chain only cases, due to the limitation of conventional methodology.

The Variations of Insulin-like Growth Factor 1 Measured between Siemens Immulite, DiaSorin Liaison and IDS iSYS

Introduction/Objective

Insulin-like Growth Factor 1 (IGF-1) is a biomarker for the evaluation of growth hormone activity in the hypothalamic-pituitary axis. The current most common methodology for IGF-1 measurement is automated immunometric assays. In this study, we compared the IGF-1 on Siemens Immulite 2000, DiaSorin Liaison XL and IDS iSYS.

Methods/Case Report

Residual 30-110 serum specimens were randomly selected from routine hospital orders. IGF- 1 was measured on these three platforms and compared with Passing-Bablok regression. Bias was evaluated using the Bland-Altman method.

Results (if a Case Study enter NA)

Weighted Deming regression analysis showed approximately 80% and 56% positive bias on IDS iSYS and DiaSorin Liaison, compared with Siemens Immulite (iSYS=1.81*Immulite-117.65, r=0.91; Liaison=1.56*Immulite-4.58, r=0.98). There was approximately 8% positive bias on Liaison, compared with iSYS (Liaison=1.08*iSYS+0.56, r=0.99). The Passing-Bablok regression analysis revealed approximately 67% and 54% positive bias (iSYS=1.67*Immulite-75, r=0.91; Liaison=1.54*Immulite-3.44, r=0.91). Approximately 8% positive bias on Liaison was observed, compared with iSYS (Liaison=1.08*iSYS+5.65, r=0.99). The Bland-Altman plot showed the agreement between iSYS and Immulite IGF-1 was on average 129.6±123.3 ng/mL, 98.6±148.8 ng/mL between Liaison and Immulite and 37.0±46.5 ng/mL between Liaison and iSYS.

Conclusion

Immunoassays rely on the specificity of antibodies. There are wide variations between different immunoassay platforms for IGF-1 measurement. The standardization of IGF-1 assay is lack. It would be a challenge for clinicians to monitor IGF-1 or treat the patients with pituitary disorders, when switching to another platform. The potential impact of the variations in IGF-1 measurement between different immunoassay platforms should be aware.

Development of the Asia Pacific Consortium on Osteoporosis (APCO) Framework: clinical standards of care for the screening, diagnosis, and management of osteoporosis in the Asia-Pacific region

Guidelines for doctors managing osteoporosis in the Asia-Pacific region vary widely. We compared 18 guidelines for similarities and differences in five key areas. We then used a structured consensus process to develop clinical standards of care for the diagnosis and management of osteoporosis and for improving the quality of care.

PURPOSE

Minimum clinical standards for assessment and management of osteoporosis are needed in the Asia-Pacific (AP) region to inform clinical practice guidelines (CPGs) and to improve osteoporosis care. We present the framework of these clinical standards and describe its development.

METHODS

We conducted a structured comparative analysis of existing CPGs in the AP region using a "5IQ" model (identification, investigation, information, intervention, integration, and quality). One-hundred data elements were extracted from each guideline. We then employed a four-round Delphi consensus process to structure the framework, identify key components of guidance, and develop clinical care standards.

RESULTS

Eighteen guidelines were included. The 5IQ analysis demonstrated marked heterogeneity, notably in guidance on risk factors, the use of biochemical markers, self-care information for patients, indications for osteoporosis treatment, use of fracture risk assessment tools, and protocols for monitoring treatment. There was minimal guidance on long-term management plans or on strategies and systems for clinical quality improvement. Twenty-nine APCO members participated in the Delphi process, resulting in consensus on 16 clinical standards, with levels of attainment defined for those on identification and investigation of fragility fractures, vertebral fracture assessment, and inclusion of quality metrics in guidelines.

CONCLUSION

The 5IQ analysis confirmed previous anecdotal observations of marked heterogeneity of osteoporosis clinical guidelines in the AP region. The Framework provides practical, clear, and feasible recommendations for osteoporosis care and can be adapted for use in other such vastly diverse regions. Implementation of the standards is expected to significantly lessen the global burden of osteoporosis.

A Malaysian Delphi consensus on managing knee osteoarthritis

BACKGROUND

The 2013 Malaysian Clinical Practice Guidelines on the Management of Osteoarthritis (OA) recommend a linear step-up approach to manage knee OA. However, patients with knee OA often require a multimodal approach to address OA-related pain symptoms and functional limitations. This consensus aimed to provide doctors with an updated set of evidence-based, clinical experience-guided recommendations to manage knee OA.

METHODS

A multi-speciality expert panel consisting of nine Malaysian physicians from different healthcare settings who manage a diverse OA patient population was convened. Using a combination of the ADAPTE process and modified Delphi method, the panel reviewed current evidence on the management of knee OA and synthesised a set of nine recommendations on the management of knee OA, supported by an algorithm that summarises the consensus' core messages.

RESULTS

A multimodal intervention strategy is the mainstay of OA management and the choice of any single or multimodal intervention may vary over the course of the disease. Overall, a non-pharmacological core treatment set of patient education, weight loss and exercise is recommended for all patients. When pharmacotherapy is indicated, symptomatic slow-acting drugs for osteoarthritis are recommended at the early stage of disease, and they can be paired with physical therapy as background treatment. Concurrent advanced pharmacotherapy that includes non-steroidal anti-inflammatory drugs, intraarticular injections and short-term weak opioids can be considered if patients do not respond sufficiently to background treatment. Patients with severe symptomatic knee OA should be considered for knee replacement surgery. Management should begin with specific treatments with the least systemic exposure or toxicity, and the choice of treatment should be determined as a shared decision between patients and their team of healthcare providers.

CONCLUSIONS

This consensus presents nine recommendations that advocate an algorithmic approach in the management of patients living with knee OA. They are applicable to patients receiving treatment from primary to tertiary care providers in Malaysia as well as other countries.

Targeting the Fragility Fracture Prevention Message

Background: The impact of fragility fractures on human suffering is underappreciated. Fragility fractures increase mortality and the risk of recurrent fracture. Notwithstanding these facts, only a minority of patients suffering osteoporotic fractures receive fracture preventing therapy. Education about the burden of disease and the benefits of prompt treatment are important means to increase the treatment rate. We propose that the focus of the educational message should be varied for distinct audiences.

Method: We searched existing literature to determine perceptions about the importance of treating fractures and osteoporosis among the following groups: the general population, primary care physicians, specialist physicians, hospital administrators, and government health officials.

Result: Extensive data focusing on patients and primary care physicians exist about barriers to treatment initiation. In these groups, lack of perceived treatment benefit is a widespread, common finding. To address this gap, we have produced a primary care education toolkit, patient booklet and education directory as Asia Pacific Fragility Fracture Alliance (APFFA)-sponsored initiatives.

Data are more limited for specialist physicians, hospital administrators, and government officials. Health economic arguments have been found to be persuasive among policy makers.

Conclusion: Information about the importance of treating fragility fractures and osteoporosis is far more abundant with reference to patients and primary care providers than to specialty physicians, hospital administrators, and government officials. Understanding the state of knowledge and belief is an essential first step in developing educational materials that address the concerns and misperceptions of each key constituency. Existing data suggest that patients will be more receptive to materials emphasising independence and quality of life, while policy makers will be more receptive to materials highlighting the burden of disease.

Blindness increases the risk for hip fracture and vertebral fracture but not the risk for distal radius fracture: a longitudinal follow-up study using a national sample cohort

The risks for hip fracture and vertebral fracture, but not the risk for distal radius fracture, were significantly higher in the blindness group than in the control group with a maximum 12-year follow-up.

PURPOSE

To evaluate the influence of visual impairment on the risk for osteoporotic fractures at common sites: hip, thoracic/lumbar vertebra, and distal radius.

METHODS

This longitudinal follow-up study used a database of a national sample cohort from 2002 to 2013 provided by the Korean National Health Insurance Service. Of a total of 1,125,691 subjects, 3918 patients with visual impairment and age ≥ 50 years were enrolled in a 1:4 ratio; 15,672 control participants were matched for age, sex, income, and region of residence. Stratified Cox proportional-hazards models were used to evaluate the crude and adjusted (for steroid medication, rheumatoid arthritis, depression, osteoporosis, diabetes mellitus, and stroke history) hazard ratios (HRs) for each fracture site. Fracture diagnoses were based on the ICD-10 codes: hip fracture (S720, S721, S722), vertebral fracture (S220, S320), and distal radius fracture (S525).

RESULTS

The HRs for hip and vertebral fracture were significantly higher in the blindness group (adjusted HR = 2.46, p < 0.001 for hip fracture; adjusted HR = 1.42, p = 0.020 for thoracic/lumbar vertebral fracture) than in the matched control group. However, the HR for distal radius fracture was not higher in the blindness group. The HRs for all three fracture sites were not significantly higher in the non-blindness visual impairment group after adjustment.

CONCLUSION

The risks for hip fracture and vertebral fracture were significantly higher in the blindness group. However, the risk for distal radius fracture was not related to visual impairment including blindness.

The Current and Future Challenges of Hip Fracture Management in Malaysia

By 2050, it is predicted that six million hip fractures will occur each year of which the majority will happen in Asia. Malaysia is not spared from this predicted rise and its rate of increase will be one of the highest in this region. Much of this is driven by our unprecedented growth in the number of older people. Characteristics of individuals with hip fractures in Malaysia mirror what has been reported in other countries. They will be older multimorbid people who were already at risk of falls and fractures. Outcomes were poor with at least a quarter do not survive beyond 12 months and in those that do survive have limitation in their mobility and activities of daily living. Reviewing how these fractures are managed and incorporating new models of care, such as orthogeriatric care, could address these poor outcomes. Experts have warned of the devastating impact of hip fracture in Malaysia and that prompt action is urgently required. Despite that, there remains no national agenda to highlight the need to improve musculoskeletal health in the country.

Secondary prevention of fragility fractures in Asia Pacific: an educational initiative

The Asia -Pacific Bone Academy (APBA) Fracture Liaison Service (FLS) Focus Group educational initiative has stimulated activity across the Asia -Pacific region with the intention of supporting widespread implementation of new FLS. In 2017, the APBA FLS Focus Group developed a suite of tools to support implementation of FLS across the Asia-Pacific region as a component of a multi-faceted educational initiative. This article puts this initiative into context with a narrative review describing the burden of fragility fractures in the region, the current secondary fracture prevention care gap and a summary of emerging best practice. The results of a survey to evaluate the impact of the APBA educational initiative is presented, in addition to commentary on recent activities intended to improve the care of individuals who sustain fragility fractures across the Asia -Pacific. A FLS Toolbox for Asia-Pacific was developed which included the following sections:1. The burden of fragility fractures in the Asia-Pacific region.2. A summary of evidence for FLS in the Asia-Pacific.3. A generic, fully referenced FLS business plan template.4. Potential cost savings accrued by each country, based on a country-specific FLS Benefits Calculator.5. How to start and expand FLS programmes in the Asia-Pacific context.6. A step-by-step guide to setting up FLS in countries in the Asia-Pacific region.7. Other practical tools to support FLS establishment.8. FLS online resources and publications.The FLS Toolbox was provided as a resource to support FLS workshops immediately following the 5th Scientific Meeting of the Asian Federation of Osteoporosis Societies (AFOS) held in Kuala Lumpur in October 2017. The FLS workshops addressed three key themes:• The FLS business case.• Planning the FLS patient pathway.• The role of the FLS coordinator in fragility fracture care management.A follow-up survey of 142 FLS workshop participants was conducted in August-September 2018. The survey included questions regarding how FLS were developed, funded, the scope of service provision and the support provided by the educational initiative. Almost one-third (30.3%) of FLS workshop participants completed the survey. Survey responses were reported for those who had established a FLS at the time the survey was conducted and, separately, for those who had not established a FLS. Findings for those who had established a FLS included:• 78.3% of respondents established a multidisciplinary team to develop the business case for their FLS.• 87.0% of respondents stated that a multidisciplinary team was established to design the patient pathway for their FLS.• 26.1% of respondents stated that their FLS has sustainable funding.• The primary source of funding for FLS was from public hospitals (83.3%) as compared with private hospitals (16.7%).Most hospitals that had not established a FLS at the time the survey was conducted were either in the process of setting-up a FLS (47%) or had plans in place to establish a FLS for which approval is being sought (29%). The primary barrier to establishing a new FLS was lack of sustainable funding. The APBA FLS Focus Group educational initiative has stimulated activity across the Asia-Pacific region with the intention of supporting widespread implementation of new FLS. A second edition of the FLS Toolbox is in development which is intended to complement ongoing efforts throughout the region to expedite widespread implementation of FLS.

Measurement of R(D) and R(D^{*}) with a Semileptonic Tagging Method

The experimental results on the ratios of branching fractions R(D)=B(B[over ¯]→Dτ^{-}ν[over ¯]_{τ})/B(B[over ¯]→Dℓ^{-}ν[over ¯]_{ℓ}) and R(D^{*})=B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D^{*}), based on a data sample containing 772×10^{6}  BB[over ¯] events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D^{*})=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D^{*}), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D^{*}) performed to date as well as the first result for R(D) based on a semileptonic tagging method.

Correction to: Algorithm for the management of patients at low, high and very high risk of osteoporotic fractures

The article 'Algorithm for the management of patients at low, high and very high risk of osteoporotic fractures',written by J. A. Kanis, was originally published Online First without Open Access. After publication in volume [#], issue [#] and page [#-#], the author decided to opt for Open Choice and to make the article an Open Access publication.

Surgical treatment of nasolabial cysts in a single institute

OBJECTIVES

To analyse the results of treatment for nasolabial cysts according to whether an intraoral sublabial or endoscopic transnasal approach was used, and to determine the recent surgical trend in our hospital.

METHODS

Twenty-four patients with a histopathologically and radiologically confirmed nasolabial cyst between January 2010 and December 2017 were enrolled in this study.

RESULTS

Nasolabial cysts were predominant in females (91.7 per cent) and on the left side (54.2 per cent). Treatment involved an intraoral sublabial approach in 12 cases (48.0 per cent) and a transnasal endoscopic approach in 13 cases (52.0 per cent). In 13 cases (52.0 per cent) surgery was performed under local anaesthesia, while in 12 cases (48.0 per cent) it was conducted under general anaesthesia. The most common post-operative complications were numbness of the upper lip or teeth (n = 9, 36.0 per cent). Only one patient (4.0 per cent), who underwent a transnasal endoscopic approach, experienced a reoccurrence.

CONCLUSION

Surgical resection through an intraoral sublabial or transnasal endoscopic approach is the best treatment for a nasolabial cyst, showing very good results and a low recurrence rate. The recent surgical trend in our hospital is to treat nasolabial cysts using a transnasal endoscopic approach under local anaesthesia.

Algorithm for the management of patients at low, high and very high risk of osteoporotic fractures

Guidance is provided in an international setting on the assessment and specific treatment of postmenopausal women at low, high and very high risk of fragility fractures.

INTRODUCTION

The International Osteoporosis Foundation and European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis published guidance for the diagnosis and management of osteoporosis in 2019. This manuscript seeks to apply this in an international setting, taking additional account of further categorisation of increased risk of fracture, which may inform choice of therapeutic approach.

METHODS

Clinical perspective and updated literature search.

RESULTS

The following areas are reviewed: categorisation of fracture risk and general pharmacological management of osteoporosis.

CONCLUSIONS

A platform is provided on which specific guidelines can be developed for national use to characterise fracture risk and direct interventions.

65 Fragility Fracture Network (FFN) Malaysia - A Call to Action for Better Outcome in Malaysia

Introduction

The incidences of hip fractures are increasing worldwide and over 50% of all hip fractures are projected to occur in Asia. Malaysia is predicted to have the highest rate of increase in numbers of hip fracture in Asia Pacific by 2050. Despite the health and economic burden associated with fragility fractures, there is limited systematic guidance or nationwide interventions set up to address this foreseeable tsunami in Malaysia. This has called for the formation of a national Fragility Fracture Network to bring together experts from different disciplines nationally to drive policy change and improve quality of care in patients with fragility fracture.

Method

The Asia Pacific Regional Fragility Fracture Summit held in Singapore in May 2018 brought together representatives of regional societies from geriatrics, orthopedic, osteoporosis and rehabilitation to share key challenges in providing optimal fragility fracture care. Three clinicians from Malaysia representing three different societies in Asia Pacific who attended the summit initiated the idea of forming a national multidisciplinary network to focus on improving acute hip fracture care, post-acute care rehabilitation and secondary fracture prevention.

Results

After the first meeting held in June 2018 with only 4 members in Kuala Lumpur, the network has expanded to include members from 7 different states in Malaysia. This has led to the formation of the Fragility Fracture Network (FFN) Malaysia in August 2018. The key goals of the network include the development of clinical hip fracture care pathway, initiating national hip fracture registry and fracture liaison service.

Conclusion

FFN Malaysia serves as a platform to unite healthcare providers and policy makers in prioritizing and having co-ownership in improving fragility fracture care in the country.

Outcomes of treatment of mammary analogue secretory carcinoma of the parotid gland

Mammary analogue secretory carcinoma (MASC) of the salivary gland is a newly-described, rare, malignant tumour. Few patients present with MASC of the parotid gland, so the exact characteristics, outcomes of treatment, and prognosis are unknown. The aim of this study was to analyse the clinical features and outcomes of treatment of MASC of the parotid gland in patients being treated at a single hospital. Five patients with histopathologically-confirmed MASC of the parotid gland between January 2015 and August 2018 were retrospectively enrolled. In all cases preoperative fine-needle aspiration cytology had failed to provide an accurate diagnosis. All patients underwent a macroscopically complete oncological resection. Two patients had postoperative radiotherapy (RT). On immunohistochemical examination all tumours stained for S-100 and mammaglobin but not for DOG1. There were no regional recurrences or distant metastases in any of the patients at their last follow-up. We obtained good results for patients with MASC of the parotid gland with surgical treatment and postoperative RT.

Dental implant and fungus ball in the ethmoid sinus

Dental migration into the ethmoid sinus is extremely rare. Furthermore, it is very unusual that a displaced dental implant is associated with a concomitant fungus ball in the ethmoid sinus. Herein, we report an unusual case of the coexistence of a dental implant and fungus ball in the ethmoid sinus. It appears that this condition has not been reported previously.

C-band PAM-4 signal transmission using soft-output MLSE and LDPC code

We propose a DSP scheme with soft-output maximum likelihood sequence equalizer (sMLSE) and low-overhead (8.51%) low density parity check (LDPC) code for C-band PAM-4 transmission. In order to apply LDPC code in conjunction with MLSE, the conventional hard-output MLSE is modified to have a soft-output value by using the Max-log BCJR algorithm. The feasibility of this approach is experimentally investigated in a 56 Gb/s C-band PAM-4 system. In order to investigate the advantages of the proposed scheme, we compare the performance of the sMLSE-LDPC code to that of MLSE-RS code. Relatively, additional OSNR gain of 0.6 dB ~2.1 dB is achieved. The variation of the relative OSNR gain depends on the burst errors, which originate from the power fading effect. By using an interleaver that spreads burst errors in time, one can see that the relative OSNR gain is improved as 1.6 dB ~2.1 dB. Using the proposed scheme with the interleaver, one can see that the 30 km transmission of 56 Gb/s PAM-4 in the C-band was experimentally demonstrated.

Correction to: Consensus on best practice standards for Fracture Liaison Service in the Asia-Pacific region

In this article the name of the sixth author, E. Michael Lewiecki was rendered incorrectly. The publisher regrets this error and apologizes for the inconvenience caused.

Case reports of atrial and pericardial rupture from blunt cardiac trauma

Background

Blunt cardiac trauma is diagnosed in less than 10% of trauma patients and covers the range of severity from clinically insignificant myocardial contusions to lethal multi-chamber cardiac rupture. The most common mechanisms of injury include: motor vehicle collisions (MVC), pedestrians struck by motor vehicles and falls from significant heights. A severe complication from blunt cardiac trauma is cardiac chamber rupture with pericardial tear. It is an exceedingly rare diagnosis. A retrospective review identified only 0.002% of all trauma patients presented with this condition. Most patients with atrial rupture do not survive transport to the hospital and upon arrival diagnosis remains difficult.

Case presentation

We present two cases of atrial and pericardial rupture. The first case is a 33-year-old female involved in a MVC, who presented unresponsive, hypotensive and tachycardic. A left sided hemothorax was diagnosed and a chest tube placed with 1200 mL of bloody output. The patient was taken to the OR emergently. Intraoperatively, a laceration in the right pericardium and a 3 cm defect in the anterior, right atrium were identified. Despite measures to control hemorrhage and resuscitate the patient, the patient did not survive.

The second case is a 58-year-old male involved in a high-speed MVC. Similar to the first case, the patient presented unresponsive, hypotensive and tachycardic with a left sided hemothorax. A chest tube was placed with 900 mL of bloody output. Based on the output and ongoing resuscitation requirements, the patient was taken to the OR. Intraoperatively, a 15 cm anterior pericardial laceration was identified. Through the defect, there was brisk bleeding from a 1 cm laceration on the left atrial appendage. The injury was debrided and repaired using a running 3–0 polypropylene suture over a Satinsky clamp. The patient eventually recovered and was discharged home.

Conclusions

We present two cases of uncontained atrial and pericardial rupture from blunt cardiac trauma. Contained ruptures with an intact pericardium present as a cardiac tamponade while uncontained ruptures present with hemomediastinum or hemothorax. A high degree of suspicion is required to rapidly diagnose and perform the cardiorrhaphy to offer the best chance at survival.

Standardisation of defined approaches for skin sensitisation testing to support regulatory use and international adoption: position of the International Cooperation on Alternative Test Methods

Skin sensitisation is the regulatory endpoint that has been at the centre of concerted efforts to replace animal testing in recent years, as demonstrated by the Organisation for Economic Co-operation and Development (OECD) adoption of five non-animal methods addressing mechanisms under the first three key events of the skin sensitisation adverse outcome pathway. Nevertheless, the currently adopted methods, when used in isolation, are not sufficient to fulfil regulatory requirements on the skin sensitisation potential and potency of chemicals comparable to that provided by the regulatory animal tests. For this reason, a number of defined approaches integrating data from these methods with other relevant information have been proposed and documented by the OECD. With the aim to further enhance regulatory consideration and adoption of defined approaches, the European Union Reference Laboratory for Alternatives to Animal testing in collaboration with the International Cooperation on Alternative Test Methods hosted, on 4-5 October 2016, a workshop on the international regulatory applicability and acceptance of alternative non-animal approaches, i.e., defined approaches, to skin sensitisation assessment of chemicals used in a variety of sectors. The workshop convened representatives from more than 20 regulatory authorities from the European Union, United States, Canada, Japan, South Korea, Brazil and China. There was a general consensus among the workshop participants that to maximise global regulatory acceptance of data generated with defined approaches, international harmonisation and standardisation are needed. Potential assessment criteria were defined for a systematic evaluation of existing defined approaches that would facilitate their translation into international standards, e.g., into a performance-based Test Guideline. Informed by the discussions at the workshop, the ICATM members propose practical ways to further promote the regulatory use and facilitate adoption of defined approaches for skin sensitisation assessments.

Altering surface fluctuations by blending tethered and untethered chains

"Partially tethering" a thin film of a polymer melt by covalently attaching to the substrate a fraction of the chains in an unentangled melt dramatically increases the relaxation time of the surface height fluctuations. This phenomenon is observed even when the film thickness, h, is 20 times the unperturbed chain radius, R_g,tethered, of the tethered chains, indicating that partial tethering is more influential than any physical attraction with the substrate. Furthermore, a partially tethered layer of a low average molecular weight of 5k showed much slower surface fluctuations than did a reference layer of pure untethered chains of much greater molecular weight (48k), so the partial tethering effect is stronger than the effects of entanglement and increase in glass transition temperature, T_g, with molecular weight. Partial tethering offers a means of tailoring these fluctuations which influence wetting, adhesion, and tribology of the surface.

Correlation of insulin-like growth factor 1 and osteoarthritic cartilage degradation: a spontaneous osteoarthritis in guinea-pig

OBJECTIVE

The pathogenesis of osteoarthritis centers on the imbalance between catabolic and anabolic processes in cartilage metabolism. Insulin growth factor 1 (IGF-1) has been shown to have anabolic effects in cartilage in vitro. This study aim to determine whether IGF-1 on cartilage is associated with loss of chondrocyte and extracellular matrix breakdown using the Hartley guinea pig model.

MATERIALS AND METHODS

Cartilage from the medial and lateral tibial plateau of 6-month and 12-month old Hartley guinea pigs were used for this study. Histological analysis was performed with hematoxylin-eosin (HE) and toluidine blue staining. Safranin-O staining was used to quantify proteoglycan (PG) loss and the extent of cartilage damage by Modified Mankin score. Distribution of IGF-1 was demonstrated with in situ hybridization techniques. IGF-1 mRNA levels were assessed using Real-time PCR.

RESULTS

Histological loss of chondrocytes, and cartilage matrix and decreased IGF-1 distribution were demonstrated in a temporal and spatial manner. Compared to the 6-month old samples, the 12-month specimens had significantly cartilage degeneration and less cartilage matrix and PGs staining. Decreased level of IGF-1 was also observed in the 12-month samples. These observations were more pronounced in the medial tibial plateau when compared to the lateral plateau.

CONCLUSIONS

The decreased level of IGF-1 may play a critical role for maintaining the balance between catabolic and anabolic processes in cartilage metabolism during the development of osteoarthritis. Thus, the increase of IGF-1 may be applicable to developing OA therapy.

Genetic diversity and population structure analysis in Perilla frutescens from Northern areas of China based on simple sequence repeats

In this study, 21 simple sequence repeat (SSR) markers were used to evaluate the genetic diversity and population structure among 77 Perilla accessions from high-latitude and middle-latitude areas of China. Ninety-five alleles were identified with an average of 4.52 alleles per locus. The average polymorphic information content (PIC) and genetic diversity values were 0.346 and 0.372, respectively. The level of genetic diversity and PIC value for cultivated accessions of Perilla frutescens var. frutescens from middle-latitude areas were higher than accessions from high-latitude areas. Based on the dendrogram of unweighted pair group method with arithmetic mean (UPGMA), all accessions were classified into four major groups with a genetic similarity of 46%. All accessions of the cultivated var. frutescens were discriminated from the cultivated P. frutescens var. crispa. Furthermore, most accessions of the cultivated var. frutescens collected in high-latitude and middle-latitude areas were distinguished depending on their geographical location. However, the geographical locations of several accessions of the cultivated var. frutescens have no relation with their positions in the UPGMA dendrogram and population structure. This result implies that the diffusion of accessions of the cultivated Perilla crop in the northern areas of China might be through multiple routes. On the population structure analysis, 77 Perilla accessions were divided into Group I, Group II, and an admixed group based on a membership probability threshold of 0.8. Finally, the findings in this study can provide useful theoretical knowledge for further study on the population structure and genetic diversity of Perilla and benefit for Perilla crop breeding and germplasm conservation.

Prevalence of Traumatic Findings on Routine MRI in a Large Cohort of Professional Fighters

BACKGROUND AND PURPOSE

Previous studies investigating MR imaging abnormalities among fighters have had small sample sizes. This investigation assessed a large number of fighters using the same conventional sequences on the same scanner.

MATERIALS AND METHODS

Conventional 3T MR imaging was used to assess 499 fighters (boxers, mixed martial artists, and martial artists) and 62 controls for nonspecific WM changes, cerebral microhemorrhage, cavum septum pellucidum, and cavum vergae. The lengths of the cavum septum pellucidum and cavum vergae and the ratio of cavum septum pellucidum to the septum pellucidum lengths were assessed.

RESULTS

The prevalence of nonspecific WM changes was similar between groups. Fighters had a prevalence of cerebral microhemorrhage (4.2% versus 0% for controls, P = .152). Fighters had a higher prevalence of cavum septum pellucidum versus controls (53.1% versus 17.7%, P < .001) and cavum vergae versus controls (14.4% versus 0%, P < .001). The lengths of the cavum septum pellucidum plus the cavum vergae (P < .001), cavum septum pellucidum (P = .025), and cavum septum pellucidum to the septum pellucidum length ratio (P = .009) were higher in fighters than in controls. The number of fights slightly correlated with cavum septum pellucidum plus cavum vergae length (R = 0.306, P < .001) and cavum septum pellucidum length (R = 0.278, P < .001). When fighters were subdivided into boxers, mixed martial artists, and martial artists, results were similar to those in the whole-group analysis.

CONCLUSIONS

This study assessed MR imaging findings in a large cohort demonstrating a significantly increased prevalence of cavum septum pellucidum among fighters. Although cerebral microhemorrhages were higher in fighters than in controls, this finding was not statistically significant, possibly partially due to underpowering of the study.

Gas-Phase Conformations and N-Glycosidic Bond Stabilities of Sodium Cationized 2'-Deoxyguanosine and Guanosine: Sodium Cations Preferentially Bind to the Guanine Residue

2'-Deoxyguanosine (dGuo) and guanosine (Guo) are fundamental building blocks of DNA and RNA nucleic acids. In order to understand the effects of sodium cationization on the gas-phase conformations and stabilities of dGuo and Guo, infrared multiple photon dissociation (IRMPD) action spectroscopy experiments and complementary electronic structure calculations are performed. The measured IRMPD spectra of [dGuo+Na]⁺ and [Guo+Na]⁺ are compared to calculated IR spectra predicted for the stable low-energy structures computed for these species to determine the most favorable sodium cation binding sites, identify the structures populated in the experiments, and elucidate the influence of the 2'-hydroxyl substituent on the structures and IRMPD spectral features. These results are compared with those from a previous IRMPD study of the protonated guanine nucleosides to elucidate the differences between sodium cationization and protonation on structure. Energy-resolved collision-induced dissociation (ER-CID) experiments and survival yield analyses of protonated and sodium cationized dGuo and Guo are performed to compare the effects of these cations toward activating the N-glycosidic bonds of these nucleosides. For both [dGuo+Na]⁺ and [Guo+Na]⁺, the gas-phase structures populated in the experiments are found to involve bidentate binding of the sodium cation to the O6 and N7 atoms of guanine, forming a 5-membered chelation ring, with guanine found in both anti and syn orientations and C2'-endo (²T₃ or ³T₂) puckering of the sugar. The ER-CID results, IRMPD yields and the computed C1'-N9 bond lengths indicate that sodium cationization activates the N-glycosidic bond less effectively than protonation for both dGuo and Guo. The 2'-hydroxyl substituent of Guo is found to impact the preferred structures very little except that it enables a 2'OH···3'OH hydrogen bond to be formed, and stabilizes the N-glycosidic bond relative to that of dGuo in both the sodium cationized and protonated complexes.

Sclerosing mucoepidermoid carcinoma of the sublingual gland

INTRODUCTION

Sclerosing mucoepidermoid carcinoma of the salivary gland is a rare subtype of mucoepidermoid carcinoma. The most common site of sclerosing mucoepidermoid carcinoma of the salivary glands is the parotid gland, followed by the submandibular gland, and the minor salivary glands.

OBSERVATION

Here we report the first case of sclerosing mucoepidermoid carcinoma of the sublingual gland.

DISCUSSION

Clinicians should consider sclerosing mucoepidermoid carcinoma in the differential diagnosis of salivary gland neoplasm. Surgical excision with clear margins seems to be a sufficient initial treatment option for sclerosing mucoepidermoid carcinoma of the salivary gland.

Rickettsia parkeri and "Candidatus Rickettsia andeanae" in Questing Amblyomma maculatum (Acari: Ixodidae) From Mississippi

Amblyomma maculatum Koch (Acari: Ixodidae), the primary vector for Rickettsia parkeri, may also be infected with a rickettsia of unknown pathogenicity, "Candidatus Rickettsia andeanae." Infection rates with these rickettsiae vary geographically, and coinfected ticks have been reported. In this study, infection rates of R. parkeri and "Ca. R. andeanae" were evaluated, and rickettsial DNA levels quantified, in 335 questing adult A. maculatum collected in 2013 (n = 95), 2014 (n = 139), and 2015 (n = 101) from Oktibbeha County, MS. Overall infection rates of R. parkeri and "Ca. R. andeanae" were 28.7% and 9.3%, respectively, with three additional A. maculatum (0.9%) coinfected. While R. parkeri-infected ticks were detected all three years (34.7% in 2013; 13.7% in 2014; 43.6% in 2015), "Ca. R. andeanae" was not detected in 2013, and was detected at rates of 10.8% in 2014, and 15.8% in 2015. Interestingly, rickettsial DNA levels in singly-infected ticks were significantly lower in "Ca. R. andeanae"-infected ticks compared to R. parkeri-infected ticks (P < 0.0001). Thus, both infection rates and rickettsial DNA levels were higher for R. parkeri than "Ca. R. andeanae." Infection rates of R. parkeri were also higher, and "Ca. R. andeanae" lower, here compared to A. maculatum reported previously in Kansas and Oklahoma. As we continue to monitor infection rates and levels, we anticipate that understanding temporal changes will improve our awareness of human risk for spotted fever rickettsioses. Further, these data may lead to additional studies to evaluate potential interactions among sympatric Rickettsia species in A. maculatum at the population level.

An update of the Malaysian Clinical Guidance on the management of glucocorticoid-induced osteoporosis, 2015

Objectives

This Clinical Guidance is aimed to help practitioners assess, diagnose and manage their patients with glucocorticoid-induced osteoporosis (GIO), using the best available evidence.

Methods

A literature search using PubMed (MEDLINE) and The Cochrane Library identified all relevant articles on GIO and its assessment, diagnosis and treatment, from 2011, to update from the 2012 edition. The studies were assessed and the level of evidence assigned. For each statement, studies with the highest level of evidence were used to frame the recommendation.

Results

Consider treatment early in all patients on glucocorticoids (GC) as fracture risk increases within 3–6 months of starting GC. The decision to start treatment for GIO depends on the presence of prior fracture, category of risk (as calculated using Fracture Risk Assessment Tool), daily dose and duration of GC treatment, age, and menopausal status. General measures include adequate calcium and vitamin D intake and reducing the dose of GC to the minimum required to achieve disease control. In patients on GC with osteoporotic fractures or confirmed osteoporosis on dual-energy X-ray absorptiometry, bisphosphonates are the first-line treatment. Treatment should be continued as long as patients remain on GC. Algorithms for the management of GIO in both pre- and post-menopausal women and men have been updated.

Conclusions

In post-menopausal women and men above 50 years, bisphosphonates remain the mainstay of treatment in GIO. In pre-menopausal women and men below 50 years, bisphosphonates are recommended for those with a prevalent fracture or at very high risk only.

Deformation mechanisms to ameliorate the mechanical properties of novel TRIP/TWIP Co-Cr-Mo-(Cu) ultrafine eutectic alloys

In the present study, the microstructural evolution and the modulation of the mechanical properties have been investigated for a Co-Cr-Mo (CCM) ternary eutectic alloy by addition of a small amount of copper (0.5 and 1 at.%). The microstructural observations reveal a distinct dissimilarity in the eutectic structure such as a broken lamellar structure and a well-aligned lamellar structure and an increasing volume fraction of Co lamellae as increasing amount of copper addition. This microstructural evolution leads to improved plasticity from 1% to 10% without the typical tradeoff between the overall strength and compressive plasticity. Moreover, investigation of the fractured samples indicates that the CCMCu alloy exhibits higher plastic deformability and combinatorial mechanisms for improved plastic behavior. The improved plasticity of CCMCu alloys originates from several deformation mechanisms; i) slip, ii) deformation twinning, iii) strain-induced transformation and iv) shear banding. These results reveal that the mechanical properties of eutectic alloys in the Co-Cr-Mo system can be ameliorated by micro-alloying such as Cu addition.

Activation of Vanilloid Receptor 1 (VR1) by Eugenol

The structural similarity of eugenol with capsaicin suggests that these two agents may share molecular mechanisms to produce their effects. We investigated the effects of eugenol in comparison with those of capsaicin using whole-cell patch clamp and Fura-2-based calcium-imaging techniques in a heterologous expression system and with sensory neurons. In vanilloid receptor 1 (VR1)-expressing human embryonic kidney (HEK) 293 cells and trigeminal ganglion (TG) neurons, eugenol activated inward currents, whereas capsazepine, a competitive VR antagonist, and ruthenium red (RR), a functional VR antagonist, completely blocked eugenol-induced inward currents. Moreover, eugenol caused elevation of [Ca2+]i, and this was completely abolished by both capsazepine and ruthenium red in VR1-expressing HEK 293 cells and TG neurons. Our results provide strong evidence that eugenol produces its effects, at least in part, via VR1 expressed by the sensory nerve endings in the teeth.

Influence of Sodium Cationization versus Protonation on the Gas-Phase Conformations and Glycosidic Bond Stabilities of 2'-Deoxyadenosine and Adenosine

The influence of noncovalent interactions with a sodium cation on the gas-phase structures and N-glycosidic bond stabilities of 2'-deoxyadenosine (dAdo) and adenosine (Ado), [dAdo+Na](+) and [Ado+Na](+), are probed via infrared multiple photon dissociation (IRMPD) action spectroscopy and energy-resolved collision-induced dissociation (ER-CID) experiments. ER-CID experiments are also performed on the protonated forms of these nucleosides, [dAdo+H](+) and [Ado+H](+), for comparison purposes. Complementary electronic structure calculations are performed to determine the structures and relative stabilities of the stable low-energy conformations of the sodium cationized nucleoside complexes and to predict their IR spectra. Comparison between the measured IRMPD action spectra and calculated IR spectra enables the conformations of the sodium cationized nucleosides present in the experiments to be elucidated. The influence of sodium cationization versus protonation on the structures and IR spectra is elucidated by comparison to IRMPD and theoretical results previously reported for the protonated forms of these nucleosides. The influence of sodium cationization versus protonation on the glycosidic bond stability of the adenine nucleosides is determined by comparison of the ER-CID behavior of these systems. All structures present in the experiments are found to involve tridentate binding of Na(+) to the N3, O4', and O5' atoms forming favorable 5- and 6-membered chelation rings, which requires that adenine rotate to a syn configuration. This mode of sodium cation binding results in moderate flexibility of the sugar moiety such that the sugar puckering of the conformations present varies between C2'-endo and O4'-endo. Sodium cationization is found to be less effective toward activating the N-glycosidic bond than protonation for both dAdo and Ado. Both the IRMPD yields and ER-CID behavior indicate that the 2'-hydroxyl substituent of Ado stabilizes the N-glycosidic bond relative to that of dAdo.

The reference phantoms: voxel vs polygon

The International Commission on Radiological Protection (ICRP) reference male and female adult phantoms, described in Publication 110, are voxel phantoms based on whole-body computed tomography scans of a male and a female patient, respectively. The voxel in-plane resolution and the slice thickness, of the order of a few millimetres, are insufficient for proper segmentation of smaller tissues such as the lens of the eye, the skin, and the walls of some organs. The calculated doses for these tissues therefore present some limitations, particularly for weakly penetrating radiation. Similarly, the Publication 110 phantoms cannot represent 8-40-µm-thick target regions in respiratory or alimentary tract organs. Separate stylised models have been used to represent these tissues for calculation of the ICRP reference dose coefficients (DCs). ICRP Committee 2 recently initiated a research project, the ultimate goal of which is to convert the Publication 110 phantoms to a high-quality polygon-mesh (PM) format, including all source and target regions, even those of the 8-40-µm-thick alimentary and respiratory tract organs. It is expected that the converted phantoms would lead to the same or very similar DCs as the Publication 110 reference phantoms for penetrating radiation and, at the same time, provide more accurate DCs for weakly penetrating radiation and small tissues. Additionally, the reference phantoms in the PM format would be easily deformable and, as such, could serve as a starting point to create phantoms of various postures for use, for example, in accidental dose calculations. This paper will discuss the current progress of the phantom conversion project and its significance for ICRP DC calculations.