How do people with chronic low back pain perceive specific and general exercise? A mixed methods survey

PURPOSE

Exercise prescriptions for chronic low back pain (CLBP) often utilize reductionistic, trunk-focused exercise aimed at addressing proposed pain mechanisms. It is unknown if the use of these trunk-focused exercises imply beliefs to people with CLBP about the rationale for their use (e.g., etiology), even without concurrent biomedical narratives. This study aimed to explore people's perceptions of specific and general exercise without an accompanying narrative when experiencing CLBP.

METHODS

An anonymous online survey was distributed. Mixed methods were utilized for analysis. Six-point Likert scales categorized people's beliefs about individual exercises. Open-ended questions were used to gather further beliefs which were then coded into themes.

RESULTS

People with CLBP perceived specific exercise as more beneficial than general exercise. Eight themes and five subthemes were defined. A high volume of positive beliefs were centered around strengthening the low back and abdominal musculature, emphasizing the importance of correct technique. Negative beliefs were held against spinal flexion and external load. Both positive and negative beliefs were underpinned by spinal/pelvic stability being important as well as certain exercises being achievable or not.

CONCLUSION

This study demonstrated that people with CLBP consider specific exercises to be more beneficial than general exercises for CLBP. Specific exercises irrespective of an accompanying narrative can imply meaning about the intent of an exercise. Understanding this requires practitioners to be mindful when prescribing and communicating exercise.

Examining HIV Organizational Structures and their Influence on Engagement with Young Black Gay, Bisexual, and other Men who have Sex with Men in Atlanta, Georgia

Young Black gay, bisexual, and other men who have sex with men (YB-GBMSM) are disproportionately impacted by HIV. Structural influences on these disparities, including characteristics of the various organizations that serve YB-GBMSM living with HIV, remain understudied. We drew on Weick's model of organizing to conduct and analyze qualitative interviews with 28 HIV service providers representing healthcare and community-based organizations in Atlanta, Georgia. Enactment of HIV service provision was described as following simplified and standardized responses-defined as "rules", and/or more dynamic exchanges to formulate responses -otherwise known as "communication behavior cycles" (CBCs). Rules, including patient quotas and limited hours of operation, were viewed as rigid, out-of-touch, and inhibiting engagement with YB-GBMSM. CBCs, such as patient feedback loops and rejection of traditional hierarchies, fostered creative insights to combating the epidemic and increased levels of cultural awareness and community buy-in. Organizations should strive to enact CBCs, to foster culturally congruent approaches to service delivery for YB-GBMSM.

Reaching and Re-Engaging People Living with HIV Who Are Out of Care: A Mixed-Methods Exploration of Patient Preferences for Strategies to Enhance Clinic Communication and Outreach

Half of all people living with HIV (PLWH) in the United States are not retained in HIV medical care. The utility of appointment reminders and clinic-based retention support services is often limited by the inability to contact PLWH who are out of care (PLWH-OOC) due to disconnected phone lines, full voice mails, and housing instability. Between June 2019 and May 2021, as part of a larger mixed-methods study in Metro Atlanta, Georgia, we conducted surveys with 50 PLWH-OOC and interviews with 13 PLWH holding a variety of clinic stakeholder roles (patients, Community Advisory Board members, and peer navigators) to explore preferences for clinic communication and peer outreach and factors impacting uptake. Although phone calls, text messages, and calling secondary contacts were most preferred, the spread of preferences was wide. Surveys and interviews highlighted the high acceptance of peer outreach visits, with trust, support, and privacy being key factors driving the uptake. Findings underscore the need for clinics to offer a suite of communication and outreach strategies and assess patient preferences for traditional and nontraditional outreach models to more effectively reach, re-engage, and ultimately retain PLWH-OOC.

One size does not fit all: Preferences for HIV care delivery among out-of-care people living with HIV in the Southeastern United States

Approximately half of the people with HIV (PWH) in the United States are retained in HIV care and only 57% have achieved viral suppression, due to barriers including transportation access, stigma, poor mental health, substance use, and medical mistrust. Community-based HIV care models have potential to address the diverse needs of patients and to improve retention in care, but their success is contingent on acceptance by patients and key community stakeholders. Recognizing that the preferences of PWH who are out-of-care (PWH-OOC) likely differ from those retained in care, we conducted a mixed-methods study from June 2019 to May 2021 composed of surveys with PWH-OOC (n = 50) and in-depth interviews with key clinic and community stakeholders (n = 41) to examine the relative preference and perceived advantages and disadvantages for six different community-based HIV care models versus the traditional fixed-clinic model. Survey data was analyzed to assess average rank preference for each care model and interview transcripts were thematically coded to examine factors influencing model acceptance. The highest preference for care delivery was via a mobile clinic, followed by community-based peer navigation, primary care clinics, telemedicine, traditional HIV subspeciality clinic, homeless shelter, and drug treatment center. Common factors influencing preference included convenience, accessibility, potential to preserve confidentiality, quality of care assurance, opportunity to develop rapport with their HIV care provider, access to a smart device, and potential to alleviate versus exacerbate HIV stigma. Participants discussed need for integration of care models and for individuals to choose different care models at different times. Providers and patients differed in preference for care model and weighting of relative advantages and disadvantages of each. Findings highlight the need to integrate alternative, community-based care models into the national plan to end the HIV epidemic and to allow for PWH-OOC to choose the model most fitting based on individual circumstances.

Feasibility and acceptability of B6: a social capital program for young Black gay, bisexual and other men who have sex with men living with HIV

Young Black gay, bisexual and other men who have sex with men (YB-GBMSM) are disproportionately burdened by HIV and often exhibit suboptimal engagement in HIV care. With the goal of increasing engagement in HIV care, we designed a culturally specific, theory-based group-level program, Brothers Building Brothers by Breaking Barriers (B6), which aimed to strengthen resilience and social capital among YB-GBMSM living with HIV. We conducted a pilot trial to evaluate the program's acceptability and feasibility. Through clinic-based recruitment and community outreach events, we recruited and enrolled 71 YB-GBMSM into the study. Participants were randomized to either the B6 program or a control comparison program. Post-session evaluation surveys and in-depth qualitative interviews showed B6 to have high levels of acceptability and satisfaction. Specifically, participants described benefits to interacting in a group with other YB-GBMSM, and several described increased comfort with their own gay identities after participation. No adverse events or safety concerns were reported. However, there were challenges to feasibility, as reflected in recruitment and retention rates. The B6 program was highly acceptable among YB-GBMSM living with HIV; however, innovative program delivery methods and implementation strategies will be needed to improve recruitment and retention in future implementation of B6.

Understanding social capital among young black gay and bisexual men living with HIV: a qualitative exploration

Social capital, defined as the sum of an individual's resource-containing, reciprocal and trustworthy social network connections, has been associated with improved engagement in care among people living with HIV globally. We conducted a qualitative interview study of social capital among 28 young Black gay, bisexual and other men who have sex with men ages 18-29 living with HIV in Atlanta, Georgia. We asked participants about bonding capital (relationships between individuals with similar demographic characteristics), bridging capital (relationships with individuals of different backgrounds), collective efficacy (involvement with community organisations) and satisfaction with their social networks. We found that participants described bonding capital from friends and family in depth, while more gaps were noted in bridging capital and collective efficacy. Bonding capital derived from families was especially critical to participants' satisfaction with their social capital. Findings suggest that interventions targeting young Black gay, bisexual and other men who have sex with men should build upon strong bonds with family and friends, and/or fill gaps in bridging capital and collective efficacy by connecting young men to mentors and organisations.

A discrete choice experiment to identify patient preferences for the provision of NHS medicines helpline services

Introduction

Medicines helplines for patients discharged from NHS hospitals can prevent medicines-related harm (1). They are an underused service, which is partly attributed to under-resourcing and consequent inability to meet NHS standards (2). There is no evidence to inform which elements of these standards should be prioritised to increase patient access.

Aim

To measure patient preferences for different attributes of the provision of medicines helpline services using a discrete choice experiment (DCE).

Methods

The International Society for Pharmacoeconomics and Outcomes Research good research practices were used to conduct a DCE. Adult members of the NHS ‘Research for the Future’ database who regularly take ≥1 prescribed medicine (or care for someone for does) completed an online survey. The survey presented ten pairs of helplines, each helpline described by seven attributes. Participants chose which helpline from each pair they would prefer to contact with a query following discharge. The attributes of each helpline were defined using standard descriptors (levels) selected with a D-efficient experimental design from two to four options. Twenty helpline pairs were blocked into two survey variants. Participants’ overall preferences for each attribute level were obtained using conditional logit regression and expressed as willingness for the NHS to pay (WTP).

Results

460 participants completed a survey (53% female, aged 20-91 years, mean number of regular medicines: 6.0). All attributes significantly affected patient preferences (p<0.001). Participants’ WTP for key characteristics are shown in the table.

Conclusion

Hospitals providing a medicines helpline should prioritise seven-day opening for extended hours with queries answered on the same day, as these attributes are valued most by potential patients. Other attributes, such as alternative means of contact or a locally based helpline are also valued, but to a lesser extent. Further analysis is required to determine the influence of participant characteristics on their preferences. Use of a DCE with experimental design and a large sample size has enabled patient preferences to be quantified with reasonable precision. However, findings are limited by the method of recruitment, as all participants had internet access and certain groups were over-represented in the sample (e.g. white ethnicity, university educated, higher income).

References

(1) Williams M, Jordan A, Scott J, Jones MD. A systematic review examining the effectiveness of medicines information services for patients and the general public. Int J Pharm Pract. 2020; 28(1): 26-40.

(2) Williams M, Jordan A, Scott J, Jones MD. Operating a patient medicines helpline: A survey study exploring current practice in England using the RE-AIM evaluation framework. BMC Health Serv Res. 2018; 18:868.

Service evaluation of the efficiency of moving discharge medicine request screening from the dispensary to hospital wards over a two-year period

Introduction

It is a common patient perception that their discharge from hospital is delayed by waiting for medicines (1). However, it is important to consider the entire discharge process when addressing this problem (2). In our large tertiary referral hospital, clinical pharmacy services were moved from wards to the dispensary following a staffing crisis during 2018. Ward-based services were reintroduced in 2020, but doubts remained over the practicality and benefits of doing this.

Aim

To compare the efficiency of ward and dispensary based clinical pharmacy services in our hospital in terms of interventions made and time taken.

Methods

We completed an observational service evaluation. Data on the time taken to process discharge medication requests with the dispensary-based service were collected retrospectively from the hospital electronic discharge system for 12 months (2018) for five medical wards. Equivalent data for the ward-based service were collected prospectively over three days (2020) by pharmacists delivering the service to seven medical wards, as this was considered more accurate, and several process steps did not exist in the ward-based model. For example, prescriber sending request to pharmacy and pharmacy acknowledging receipt of a request. The prospective data collection period was curtailed by Covid-19. Descriptive statistics were produced using Excel.

Results

Using the dispensary-based service (2018), 4459 medicine requests were processed from 5 medical wards, during a 12-month period. The mean time between prescribing and reaching the screening pharmacist was 175 minutes [95%CI ± 25.4]. It took an estimated time of 62 minutes [95%CI ± 2.99] to screen and resolve an intervention, with a mean of 3 interventions/ward/day. In 2020, using the ward-based approach to clinical pharmacy which screened medicine requests on the ward, 142 requests were screened over three days from seven wards, with no delay between prescribing and clinical screening. It took a mean of 17 minutes [95%CI ± 10.63] to screen and resolve an intervention, with a mean of 15 interventions/ward/day.

Conclusion

Ward based pharmacy yielded five times more interventions, took an average of 45 minutes less to screen and resolve issues per request and removed 175 minutes of process time. The additional time required to resolve issues identified in the dispensary-based screening process was thought to be the delay in contacting either the appropriate member of the ward staff referencing a particular patient for information or identifying and contacting the prescriber, or a combination of both. This study is limited by the long delay between data collection periods and the small sample size in 2020, but the differences between the two systems were large and there had been few other changes to hospital systems. Other limitations include changes related to Covid-19 and the lack of a control group, so it is not possible to establish a causal relationship between the type of pharmacy service and study outcomes.

References

(1) Wright S, Morecroft CW, Mullen R, Ewing AB. UK hospital patient discharge: the patient perspective. Eur J Hosp Pharm. 2017 Nov;24(6):338-342.

(2) Green CF, Hunter L, Jones L, Morris K. The TTO Journey: How much of it is actually in pharmacy? Pharm Man. 2015 Oct;31(4):16-20.

Low carbon footprint inhalers in England: a review of dispensing data

Introduction

Due to propellants, metered dose inhalers (pMDIs) have a higher carbon footprint than low carbon footprint inhalers (LCFIs), such as dry powder or soft mist inhalers (1). Consequently, pMDIs contribute 3.5% of the NHS’s CO2 equivalent emissions (2). Local and national guidelines (NICE, British Thoracic Society) have attempted to increase use of LCFIs, but their effects and factors influencing success are unknown.

Aim

To investigate temporal and geographical variation in LCFI dispensing in England over five years.

Methods

Clinical commissioning group (CCG) dispensed items (March 2016-February 2021) were obtained from openprescribing.net for five classes of inhaler where a choice between pMDIs and LCFIs is available: short-acting beta-agonists (SABAs), long-acting beta-agonists (LABAs), inhaled corticosteroids (ICS), ICS plus LABA inhalers (ICS/LABA) and ICS/LABA plus long-acting muscarinic antagonist inhalers (ICS/LABA/LAMA). CCG population age profiles were obtained from the Office for National Statistics. CCG emergency hospital admission and mortality rates were obtained from Public Health England. CCG formularies and guidelines were reviewed to identify where guidance is available to prescribers.

To control for total inhaler dispensing, the key measure used is the %LCFI: the number of LCFI items dispensed relative to the total number of pMDI and LCFI items. Multivariate regression models were used to investigate geographical variation.

Results

The total annual %LCFI increased from 19.5% to 26.3% over the study period. This was driven by the introduction of ICS/LABA/LAMA inhalers in 2018, as %LCFI decreased for SABA, ICS and ICS/LABA inhalers. %LCFI varied between classes. In the final year, it ranged from 6% for both SABA and ICS inhalers, to 41.2% and 43.9% for ICS/LABA and ICS/LABA/LAMA inhalers, respectively. Interestingly, the cost per item for ICS/LABA and ICS/LABA/LAMA inhalers was similar for both pMDIs and LCFIs, but for SABA and ICS inhalers LCFIs were more expensive.

%LCFI in the final year varied between CCGs (10.7% to 30.9%). The North West, and Birmingham and London areas had consistently higher %LCFI for all classes. For SABA and ICS inhalers, both the presence of advice on climate change in CCG guidelines or formularies, and greater CCG asthma prevalence, were significantly associated with higher %LCFI (p<0.05). The proportion of CCG population <15 years had a significant negative association with %LCFI for ICS and ICS/LABA inhalers (p<0.05). There were no clinically significant associations between %LCFI and either emergency hospital admission or mortality rates.

Conclusion

Current initiatives have not been successful in increasing the use of LCFIs, indicating limited implementation of guidelines for unknown reasons. Further action is required to reduce the carbon footprint of inhaler prescribing. Actions to address the financial disincentives to LCFI prescribing, CCG leadership (e.g. guidelines) and the appropriate use of LCFI in young people should be considered. Research into facilitators and barriers to LCFI use would support this. An important limitation is the use of dispensed items data rather than the number of inhalers, although there is no evidence that the number of inhalers per item varies between pMDIs and LCFIs. In addition, the Covid-19 pandemic disrupted prescribing patterns and long-term NHS projects.

References

(1) Wilkinson AJK, Braggins R, Steinbach I, Smith K. Costs of switching to low global warming potential inhalers. An economic and carbon footprint analysis of NHS prescription data in England. BMJ Open. 2019; 9:e028763.

(2) Environmental Audit Committee. UK progress on reducing F-Gas emissions inquiry: Fifth report of session 2017-19. London (UK): House of Commons Environmental Audit Committee; 25 April 2018. Available from https://publications.parliament.uk/pa/cm201719/cmselect/cmenvaud/469/469.pdf: [Accessed 27 September 2021].

Understanding and addressing privacy and confidentiality concerns associated with the provision of mobile HIV care: a qualitative study

Less than half the people with HIV (PLWH) in the United States (US) are retained in HIV care, underscoring the importance of novel reengagement and retention strategies. Mobile HIV clinics (MHCs) are one such strategy, but privacy and confidentiality concerns have limited their use. As part of a larger mixed-methods study in Atlanta, Georgia, from June 2019- July 2020, we conducted 41 qualitative interviews with key stakeholders to explore confidentiality, privacy and stigma concerns and strategies to address them. Interviews were recorded, transcribed and coded thematically. Four key themes emerged: 1) the need to understand MHC acceptance in the context of high HIV stigma in the South, 2) the multidimensionality of confidentiality and stigma concerns (e.g., related to exterior labeling, layout, location attracting unwanted attention), 3) the counter perspective: potential for MHCs to positively reframe HIV and reduce stigma, and 4) strategies to overcome stigma and confidentiality concerns, including co-delivery of non-HIV services, unidirectional flow, and non-HIV exterior labeling. In furthering understanding of the breadth of privacy and confidentiality concerns associated with an MHC and strategies for addressing them, this exploratory study lays a critical foundation for the development of an MHC to reengage and retain PLWH in the US.

A finite element-guided mathematical surrogate modeling approach for assessing occupant injury trends across variations in simplified vehicular impact conditions

A finite element (FE)-guided mathematical surrogate modeling methodology is presented for evaluating relative injury trends across varied vehicular impact conditions. The prevalence of crash-induced injuries necessitates the quantification of the human body's response to impacts. FE modeling is often used for crash analyses but requires time and computational cost. However, surrogate modeling can predict injury trends between the FE data, requiring fewer FE simulations to evaluate the complete testing range. To determine the viability of this methodology for injury assessment, crash-induced occupant head injury criterion (HIC₁₅) trends were predicted from Kriging models across varied impact velocities (10-45 mph; 16.1-72.4 km/h), locations (near side, far side, front, and rear), and angles (-45 to 45°) and compared to previously published data. These response trends were analyzed to locate high-risk target regions. Impact velocity and location were the most influential factors, with HIC₁₅ increasing alongside the velocity and proximity to the driver. The impact angle was dependent on the location and was minimally influential, often producing greater HIC₁₅ under oblique angles. These model-based head injury trends were consistent with previously published data, demonstrating great promise for the proposed methodology, which provides effective and efficient quantification of human response across a wide variety of car crash scenarios, simultaneously. This study presents a finite element-guided mathematical surrogate modeling methodology to evaluate occupant injury response trends for a wide range of impact velocities (10-45 mph), locations, and angles (-45 to 45°). Head injury response trends were predicted and compared to previously published data to assess the efficacy of the methodology for assessing occupant response to variations in impact conditions. Velocity and location were the most influential factors on the head injury response, with the risk increasing alongside greater impact velocity and locational proximity to the driver. Additionally, the angle of impact variable was dependent on the location and, thus, had minimal independent influence on the head injury risk.

Barriers and facilitators to use of a mobile HIV care model to re-engage and retain out-of-care people living with HIV in Atlanta, Georgia

Novel strategies to re-engage and retain people living with HIV (PLWH) who are out of care are greatly needed. While mobile clinics have been used effectively for HIV testing and linkage, evidence guiding their use in providing HIV care domestically has been limited. To guide the development of a mobile HIV clinic (MHC) model as a strategy to re-engage and retain PLWH who are out of care, we aimed to explore stakeholder perceptions of barriers and facilitators to MHC implementation and use. From June 2019-July 2020, we conducted 41 in-depth interviews with HIV clinic providers, administrators, staff, legal authorities, and community advisory board members, PLWH, AIDS service organizations and city officials in Atlanta, Georgia, and domestic and international mobile health clinics to explore barriers and facilitators to use of MHCs. Interviews were transcribed, coded and thematically analysed. Barriers raised include potential for: breach of confidentiality with resulting heightened stigmatization, fractured continuity of care, safety concerns, staffing challenges, and low community acceptance of MHC presence in their locality. Participants provided suggestions regarding appropriate exterior design, location, timing, and co-delivery of non-HIV services that could facilitate MHC acceptance and address the concerns. In identifying key barriers and facilitators to MHC use, this study informs design and implementation of an MHC as a novel strategy for re-engaging and retaining PLWH who are out of care.

Exploring influences on methamphetamine use among Black gay, bisexual and other men who have sex with men in Atlanta: A focus group study

BACKGROUND

Methamphetamine use is a contributor to HIV risk and poor health outcomes among gay, bisexual and other men who have sex with men (GBMSM). There is a paucity of research examining methamphetamine use and its social context specifically among Black GBMSM. We therefore sought to: (1) describe trends in methamphetamine use among Black GBMSM in Atlanta, Georgia, and (2) examine the risk environment (micro-, meso‑ and macro-level factors operating in the political, social, physical, economic, and healthcare environments) that might elevate risk for methamphetamine use in this population.

METHODS

We conducted a qualitative study consisting of eight focus groups with 54 key informants between December 2019 and March 2020. Participants represented community-based and healthcare organizations that work closely with Black GBMSM. Our thematic analysis included an iterative, team coding approach combining deductive and inductive elements.

RESULTS

Participants unanimously agreed that methamphetamine use was increasingly prevalent among Black GBMSM in Atlanta, with many describing a historical arc in which methamphetamine use - previously associated with predominantly white, affluent GBMSM - was now common among younger, lower socioeconomic status Black GBMSM. At the micro-level, participants described contributors to increasing methamphetamine use including use as a sex drug, and the interrelated burdens of stress and mental illness, housing instability, geographic mobility and poverty. At the meso‑level, participants described virtual and physical sex scenes including use of geosocial networking apps that facilitated the spread of methamphetamine use in the Black GBMSM community. At the macro-level, participants described how policies prioritizing other concerns (e.g., HIV, opioids) seemed to limit resources available for methamphetamine prevention and treatment programming.

CONCLUSION

Multi-level environmental influences are working together to elevate risk for methamphetamine use among Black GBMSM in Atlanta, with potential to adversely impact health and well-being and undermine HIV prevention and treatment efforts.

First Spectroscopy of the Near Drip-line Nucleus ^{40}Mg

One of the most exotic light neutron-rich nuclei currently accessible for experimental study is ^{40}Mg, which lies at the intersection of the nucleon magic number N=28 and the neutron drip line. Low-lying excited states of ^{40}Mg have been studied for the first time following a one-proton removal reaction from ^{41}Al, performed at the Radioactive Isotope Beam Factory of RIKEN Nishina Center with the DALI2 γ-ray array and the ZeroDegree spectrometer. Two γ-ray transitions were observed, suggesting an excitation spectrum that shows unexpected properties as compared to both the systematics along the Z=12, N≥20  Mg isotopes and available state-of-the-art theoretical model predictions. A possible explanation for the observed structure involves weak-binding effects in the low-lying excitation spectrum.

Characterization of activating mutations of NOTCH3 in T-cell acute lymphoblastic leukemia and anti-leukemic activity of NOTCH3 inhibitory antibodies

Notch receptors have been implicated as oncogenic drivers in several cancers, the most notable example being NOTCH1 in T-cell acute lymphoblastic leukemia (T-ALL). To characterize the role of activated NOTCH3 in cancer, we generated an antibody that detects the neo-epitope created upon gamma-secretase cleavage of NOTCH3 to release its intracellular domain (ICD3), and sequenced the negative regulatory region (NRR) and PEST domain coding regions of NOTCH3 in a panel of cell lines. We also characterize NOTCH3 tumor-associated mutations that result in activation of signaling and report new inhibitory antibodies. We determined the structural basis for receptor inhibition by obtaining the first co-crystal structure of a NOTCH3 antibody with the NRR protein and defined two distinct epitopes for NRR antibodies. The antibodies exhibit potent anti-leukemic activity in cell lines and tumor xenografts harboring NOTCH3 activating mutations. Screening of primary T-ALL samples reveals that two of 40 tumors examined show active NOTCH3 signaling. We also identified evidence of NOTCH3 activation in 12 of 24 patient-derived orthotopic xenograft models, two of which exhibit activation of NOTCH3 without activation of NOTCH1. Our studies provide additional insights into NOTCH3 activation and offer a path forward for identification of cancers that are likely to respond to therapy with NOTCH3 selective inhibitory antibodies.

Nickel-responsive regulation of two novel Helicobacter pylori NikR-targeted genes

Nickel is an essential transition metal for the survival of Helicobacter pylori in the acidic human stomach. The nickel-responsive transcriptional regulator HpNikR is important for maintaining healthy cytosolic nickel concentrations through the regulation of multiple genes, but its complete regulon and role in nickel homeostasis are not well understood. To investigate potential gene targets of HpNikR, ChIP sequencing was performed using H. pylori grown at neutral pH in nickel-supplemented media and this experiment identified HPG27_866 (frpB2) and HPG27_1499 (ceuE). These two genes are annotated to encode a putative iron transporter and a nickel-binding, periplasmic component of an ABC transporter, respectively. In vitro DNA-binding assays revealed that HpNikR binds both gene promoter sequences in a nickel-responsive manner with affinities on the order of ∼10(-7) M. The recognition sites of HpNikR were identified and loosely correlate with the HpNikR pseudo-consensus sequence (TATTATT-N11-AATAATA). Quantitative PCR experiments revealed that HPG27_866 and HPG27_1499 are transcriptionally repressed following growth of H. pylori G27 in nickel-supplemented media, and that this response is dependent on HpNikR. In contrast, iron supplementation results in activation of HPG27_1499, but no impact on the expression of HPG27_866 was observed. Metal analysis of the Δ866 strain revealed that HPG27_866 has an impact on nickel accumulation. These studies demonstrate that HPG27_866 and HPG27_1499 are both direct targets of HpNikR and that HPG27_866 influences nickel uptake in H. pylori.

A ratiometric NMR pH sensing strategy based on a slow-proton-exchange (SPE) mechanism

Real time and non-invasive detection of pH in live biological systems is crucial for understanding the physiological role of acid-base homeostasis and for detecting pathological conditions associated with pH imbalance. One method to achieve in vivo pH monitoring is NMR. Conventional NMR methods, however, mainly utilize molecular sensors displaying pH-dependent chemical shift changes, which are vulnerable to multiple pH-independent factors. Here, we present a novel ratiometric strategy for sensitive and accurate pH sensing based on a small synthetic molecule, SPE1, which exhibits exceptionally slow proton exchange on the NMR time scale. Each protonation state of the sensor displays distinct NMR signals and the ratio of these signals affords precise pH values. In contrast to standard NMR methods, this ratiometric mechanism is not based on a chemical shift change, and SPE1 binds protons with high selectivity, resulting in accurate measurements. SPE1 was used to measure the pH in a single oocyte as well as in bacterial cultures, demonstrating the versatility of this method and establishing the foundation for broad biological applications.

Effect of a Limited Iodine Diet on Iodine Uptake by Thyroid Glands in Hyperthyroid Cats

BACKGROUND

The effect of feeding a limited iodine diet on radioactive iodine uptake in the thyroid glands of hyperthyroid cats is unknown.

OBJECTIVES

To determine how feeding limited dietary iodine affects radioactive iodine uptake by the thyroid glands of hyperthyroid cats.

ANIMALS

Eight geriatric cats with spontaneous hyperthyroidism.

METHODS

Prospective study of eight client owned hyperthyroid cats fed a commercially available iodine limited diet for 6 months. Clinical signs were evaluated and TT4 and fT4 were measured during consumption of the diet. Uptake of (123)I was determined before and 8-16 weeks after exclusive consumption of the diet.

RESULTS

Clinical signs of hyperthyroidism resolved in all cats, but there was no significant increase in body weight. TT4 and fT4 decreased into the reference range by 8-16 weeks in all cats. Mean TT4 before consumption of the diet was 9.7 μg/dL (SD 5.2) and after consumption of the diet was 3.1 μg/dL (SD 0.9). Scintigraphy revealed unilateral uptake of isotope in 5 cats and bilateral uptake in 3 cats. Mean percentage uptake of (123)I by the thyroid gland at 8 hours after isotope administration was 16.2 (SD 11.8) before diet consumption and 34.6 (SD 11.7) 8-16 weeks after exclusive consumption of the diet. The percentage increase was variable between cats (38-639%).

CONCLUSIONS AND CLINICAL IMPORTANCE

Limited iodine diets increase iodine uptake in the autonomous thyroid glands of hyperthyroid cats. Further studies are necessary to determine if consumption of a limited iodine diet changes sensitivity of the thyroid gland to (131)I treatment.

Versatile cold atom source for multi-species experiments

We present a dual-species oven and Zeeman slower setup capable of producing slow, high-flux atomic beams for loading magneto-optical traps. Our compact and versatile system is based on electronic switching between different magnetic field profiles and is applicable to a wide range of multi-species experiments. We give details of the vacuum setup, coils, and simple electronic circuitry. In addition, we demonstrate the performance of our system by optimized, sequential loading of magneto-optical traps of lithium-6 and cesium-133.

Infant cervical range of motion in the sagittal plane

Background:

Data pertaining to infant sagittal cervical range of motion (CROM) is lacking. Previous studies have either quantified motions other than sagittal or quantified sagittal range of motion in children >3 years old. Data capture in infants is complex and novel methods are required to overcome previous limitations. Such data is invaluable to inform paediatric injury models, such as those for shaken baby syndrome and automotive safety.

Methods:

Nine infants were recruited from a local group of parents (mean age=406 days, SD=19). Sagittal range-of-motion was measured using two miniature accelerometers (THETAmetrix), which provide orientation angle with respect to gravity. One sensor was placed on the forehead and one over the T2–3 spinous process. Sagittal range of motion was determined by subtracting the tilt angle of thorax sensor from that of the forehead and then summing the total sagittal movement cycle to yield resultant cervical range of motion. Infants were placed in their usual highchair and encouraged to move their head into flexion and extension by a parent focussing their attention on a favourite toy. At the point of maximal motion, the lead researcher applied gentle overpressure to ensure full range was achieved with parental consent. Once one full cycle of sagittal motion was achieved, data collection was terminated.

Results:

Overpressure was not possible in two infants, therefore, their data was omitted. The mean peak sagittal range of motion was 115° (SD=12) with a 95% CI=106–124°.

Conclusions:

The described methods were successful in measuring sagittal CROM in infants and could be used to determine range of motion in even younger infants. The data produced is in agreement with previous reports on older children; however, this method overcomes limitations of other data capture methods.

Implications:

The results provide the first estimate of infant CROM. These data can serve as reference for models of musculoskeletal and neurological injury, including those for shaken baby syndrome and automotive safety.

The reliability of novel multiregional spinal motion measurement device

Background:

Current spinal range of motion (ROM) measurement methods have limitations ranging from the amount of detail obtained to environmental costs and complexity. In particular, limited regional spinal motion is obtained using the current methods. However, a new portable ‘string’ of accelerometers is proposed to overcome these limitations.

Objectives:

This study seeks to determine the reliability of this sensor string in measuring three-dimensional spinal ROM and to investigate the relative motions across six different regions.

Methods:

Two procedures were undertaken on 18 healthy participants. Protocol one: two sensors were placed on the forehead and T1 to measure cervical ROM; and protocol two: six sensors were placed on the spinous processes of T1, T4, T8, T12, L3 and S1 to measure thoraco-lumbar regional ROM.

Results:

The ICC values for all regions were found to be high, ranging from ICC=0.88–0.99 for all movements and regions of the spine, demonstrating that the proposed methods were highly reliable for repeated measures. The standard error of the means (SEMs) were small, ranging from 0.7–5.2°. The flexion/extension motion demonstrated a mean SEM of 1.9° and 1.1° for lateral bending motions. Slightly larger SEMs were observed for rotation, especially for the upper thoracic (UT) and mid thoracic (MT) region with an overall mean SEM of 3.1°. Minimum detectable change (MDC) values ranged from 1.9–14.4°. The flexion/extension motion demonstrated a mean MDC of 5.2° with 3.1° for lateral bending motions. Slightly larger MDCs were observed for rotation (mean MDC=8.4°), especially for the UT and MT region.

Implications:

This method was able to quantify the relative contribution of differing regions to the overall motion. The method described represents a reliable method of assessing spinal ROM across multiple spinal regions.

Directional next-generation RNA sequencing and examination of premature termination codon mutations in endoglin/hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) is a disease characterised by abnormal vascular structures, and most commonly caused by mutations in ENG, ACVRL1 or SMAD4 encoding endothelial cell-expressed proteins involved in TGF-β superfamily signalling. The majority of mutations reported on the HHT mutation database are predicted to lead to stop codons, either due to frameshifts or direct nonsense substitutions. The proportion is higher for ENG (67%) and SMAD4 (65%) than for ACVRL1 (42%), p < 0.0001. Here, by focussing on ENG, we report why conventional views of these mutations may need to be revised. Of the 111 stop codon-generating ENG mutations, on ExPASy translation, all except one were premature termination codons (PTCs), sited at least 50-55 bp upstream of the final exon-exon boundary of the main endoglin isoform, L-endoglin. This strongly suggests that the mutated RNA species will undergo nonsense-mediated decay. We provide new in vitro expression data to support dominant negative activity of stable truncated endoglin proteins but suggest these will not generate HHT: the single natural stop codon mutation in L-endoglin (sited within 50-55 nucleotides of the final exon-exon boundary) is unlikely to generate functional protein since it replaces the entire transmembrane domain, as would 8 further natural stop codon mutations, if the minor S-endoglin isoform were implicated in HHT pathogenesis. Finally, next-generation RNA sequencing data of 7 different RNA libraries from primary human endothelial cells demonstrate that multiple intronic regions of ENG are transcribed. The potential consequences of heterozygous deletions or duplications of such regions are discussed. These data support the haploinsufficiency model for HHT pathogenesis, explain why final exon mutations have not been detected to date in HHT, emphasise the potential need for functional examination of non-PTC-generating mutations, and lead to proposals for an alternate stratification system of mutational types for HHT genotype-phenotype correlations.

The prognostic and predictive value of serum CA19.9 in pancreatic cancer

Background

Current staging methods for pancreatic cancer (PC) are inadequate, and biomarkers to aid clinical decision making are lacking. Despite the availability of the serum marker carbohydrate antigen 19.9 (CA19.9) for over two decades, its precise role in the management of PC is yet to be defined, and as a consequence, it is not widely used.

Methods

We assessed the relationship between perioperative serum CA19.9 levels, survival and adjuvant chemotherapeutic responsiveness in a cohort of 260 patients who underwent operative resection for PC.

Results

By specifically assessing the subgroup of patients with detectable CA19.9, we identified potential utility at key clinical decision points. Low postoperative CA19.9 at 3 months (median survival 25.6 vs 14.8 months, P = 0.0052) and before adjuvant chemotherapy were independent prognostic factors. Patients with postoperative CA 19.9 levels >90 U/ml did not benefit from adjuvant chemotherapy (P = 0.7194) compared with those with a CA19.9 of ≤90 U/ml (median 26.0 vs 16.7 months, P = 0.0108). Normalization of CA19.9 within 6 months of resection was also an independent favorable prognostic factor (median 29.9 vs 14.8 months, P = 0.0004) and normal perioperative CA19.9 levels identified a good prognostic group, which was associated with a 5-year survival of 42%.

Conclusions

Perioperative serum CA19.9 measurements are informative in patients with detectable CA19.9 (defined by serum levels of >5 U/ml) and have potential clinical utility in predicting outcome and response to adjuvant chemotherapy. Future clinical trials should prioritize incorporation of CA19.9 measurement at key decision points to prospectively validate these findings and facilitate implementation.

The potential effects of floor impact surfaces on infant head injury outcome during a short fall

When considering cases of infant head injury as a result of a short fall, investigators often have to base their opinions on the potential severity of a head injury on a scene description and/or photographic evidence of the potential impact surfaces. While variation in the attenuation properties of typical domestic surfaces and underlying support structures have been reported in the literature, this study investigates whether there is a need to consider the nature and composition of specific potential impact floor surfaces/sites, within a scene, prior to providing an opinion about the likely head impact injury outcome. An instrumented headform was impacted within a suspected crime scene to determine whether different potential impact sites posed different risks of producing head injury. The impact acceleration-time waveform, for the headform, was shown to vary considerably across the floor. By applying recognized head impact injury risk measures (peak g and head injury criterion), it was illustrated that the risk of an infant sustaining a significant head injury could vary considerably, depending upon the exact point of impact with the floor. This study highlights the potential for variation in impact force across a scene and illustrates the need to consider surface composition at specific sites across the entire potential impact area, since the risk of head injury can vary significantly. Caution should therefore be exercised when expressing opinions based solely on verbal, written or photographic evidence of head impact surfaces, without due consideration of the specific area onto which a head might have impacted.

European field study of the efficacy and safety of the novel anthelmintic monepantel in sheep

During 2007, a large-scale controlled, multicentre, blinded and randomised field study was conducted in Scotland, England and France to assess the efficacy and safety of monepantel, the first molecule to be developed from the recently discovered amino-acetonitrile derivatives class of anthelmintics, in sheep. Monepantel was administered orally, at a minimum dose of 2.5 mg/kg bodyweight, for the control of gastrointestinal nematodes in sheep maintained at pasture in a range of commercial production systems. Efficacy was measured by faecal egg count (FEC) reduction tests seven days after treatment and was demonstrated to be over 98 per cent against mixed-genus infections. The reduction in FEC of monepantel-treated sheep was statistically significantly greater than in untreated control sheep (P<0.0001). The efficacy of monepantel against mixed-genus natural field infections of the major gastrointestinal nematodes was in agreement with similar studies conducted in Australia and New Zealand. There were no treatment-related adverse events during the study, which included the use of a range of concomitant treatments.

The Bio-Tribological Characteristics of Synthetic Tissue Grafts

The use of synthetic connective tissue grafts became popular in the mid-1980s, particularly for anterior cruciate ligament reconstruction; however, this trend was soon changed given the high failure rate due to abrasive wear. More than 20 years later, a vast range of grafts are available to the orthopaedic surgeon for augmenting connective tissue following rupture or tissue loss. While the biomechanical properties of these synthetic grafts become ever closer to the natural tissue, there have been no reports of their bio-tribological (i.e. bio-friction) characteristics. In this study, the bio-tribological performance of three clinically available synthetic tissue grafts, and natural tendon, was investigated. It was established that the natural tissue exhibits fluid-film lubrication characteristics and hence is highly efficient when sliding against opposing tissues. Conversely, all the synthetic tissues demonstrated boundary or mixed lubrication regimes, resulting in surface—surface contact, which will subsequently cause third body wear. The tribological performance of the synthetic tissue, however, appeared to be dependent on the macroscopic structure. This study indicates that there is a need for synthetic tissue designs to have improved frictional characteristics or to use a scaffold structure that encourages tissue in-growth. Such a development would optimize the bio-tribological properties of the synthetic tissue and thereby maximize longevity.

Band narrowing and Mott localization in iron oxychalcogenides La2O2Fe2O(Se,S)2

Bad metal properties have motivated a description of the parent iron pnictides as correlated metals on the verge of Mott localization. What has been unclear is whether interactions can push these and related compounds to the Mott-insulating side of the phase diagram. Here we consider the iron oxychalcogenides La2O2Fe2O(Se,S)2, which contain an Fe square lattice with an expanded unit cell. We show theoretically that they contain enhanced correlation effects through band narrowing compared to LaOFeAs, and we provide experimental evidence that they are Mott insulators with moderate charge gaps. We also discuss the magnetic properties in terms of a Heisenberg model with frustrating J1-J2-J2' exchange interactions on a "doubled" checkerboard lattice.

Medical engineering at Cardiff University. Part 2: Postgraduate programmes of study

The Medical Engineering team within the School of Engineering, Cardiff University, delivers two postgraduate programmes of study. Established over 10 years ago, the part-time MSc programmes in Orthopaedic Engineering and Clinical Engineering offer the opportunity of further study while remaining within full-time employment. Both programmes deliver 120 taught credits over two academic years via a series of residential weekends, with successful completion enabling the student to undertake and then defend a 60-credit research dissertation. Fulfilling a specific role on the career pathway for both student cohorts, the strength of each programme is indicated by the consistent number of applicants.

Medical engineering at Cardiff University. Part 1: Undergraduate programmes of study

Cardiff University has offered a medical engineering undergraduate programme since 2001 and hence delivers one of the longest-running and most established medical engineering programmes within the UK. It currently offers BEng (Hons) and MEng (Hons) programmes that are both accredited by the Institution of Mechanical Engineers and include the option to undertake a year in industrial employment. The admissions policy ensures that the intake consists of a diverse range of students and is typically very successful in attracting female students. The programmes consist of six key academic threads which ensure that the content is both relevant and continuous, with all threads tailored to provide a patient-focused learning environment. Students initially learn core and fundamental principles in years 1 and 2, supported by a range of laboratories and practical experimentation. The latter years then encourage the students to corroborate and apply this knowledge, including involvement in a range of project-based learning exercises. The programme is delivered by a core of experienced academic medical engineers, with support from other engineering colleagues, as well as colleagues from the School of Biosciences, the School of Medicine, and the National Health Service. Thus, the programme delivers a wide range of modules which guarantee that graduating students have a thorough understanding of all possible career options. These two factors are significant in making it possible for students to follow their chosen career path upon graduation.

Characterisation and aerosolisation of mannitol particles produced via confined liquid impinging jets

Mannitol particles, produced by spray drying (SD), have been used commercially (Aridol) in bronchial provocation test. In this study, we propose an alternative method to produce inhalable mannitol powders. The elongated mannitol particles (number median length 4.0microm, and axial ratio of 3.5) were prepared using a confined liquid impinging jets (CLIJs) followed by jet milling (JM). Spray dried and jet milled raw mannitol particles were compared in an attempt to assess the performance of the particles produced by the new method. Aerosol performance of the three different powders (CLIJ, SD, and JM) was relatively poor (fine particle fraction or FPF(loaded) below 15%) when dispersed by the Rotahaler. Dispersion through the Aeroliser led to better aerosol performance of the CLIJ mannitol (FPF(loaded) 20.3%), which is worse than the JM (FPF(loaded) 30.3%) and SD mannitol particles (FPF(loaded) 45.7%) at 60 L/min, but comparable (FPF(loaded) 40.0%) with those of the JM (FPF(loaded) 40.7%) and SD (FPF(loaded) 45.5%) powders at 100L/min. Hence, the optimum use of these elongated mannitol particles can be achieved at increased air flow with a more efficient inhaler. In addition to crystallinity, morphology, and particle size distribution, the surface energies of these powders were measured to explain the differences in aerosol performance. A major advantage of using the CLIJ method is that it can be scaled up with a good yield as the precipitate can be largely collected and recovered on a filter, compared with spray drying which has a low collection efficiency for fine particles below 2microm.

Rib fractures in infancy: establishing the mechanisms of cause from the injuries--a literature review

In the absence of a history of a significant accidental event, the most likely diagnosis in an infant with rib fractures is non-accidental injury. Medical opinion is essential when deciding if child abuse has taken place or not and this requires a consideration of whether a proposed causal explanation fits with the observed injuries. To assist in the interpretation of injuries and inform medical practitioners, it is essential to develop a clear understanding of their biomechanical mechanism of causation. The types and 'likely' mechanisms of rib fracture are well-documented, however, what forces, deflections and loading rates are required to produce particular fractures are relatively unknown. This paper presents a review of the literature, from a biomechanical engineering perspective, to assess information regarding the various types of rib fracture and their likely mechanisms, paying particular attention to the likely forces, deflections and loading rates involved. The biomechanical parameters, applied during 'two finger' infant cardiopulmonary resuscitation (CPR), are identified and discussed, and are currently believed to be below the limit at which rib fracture may occur. However, a new 'two thumb' CPR technique is identified which involves a holding/gripping mechanism of the infant thorax, similar to that which is believed to occur in inflicted injury scenarios, such as shaking. The two thumb method may provide a greater magnitude of force and deflection, a greater rate of loading and may perhaps pose a greater risk of fracture, compared with the 'two finger' supine, anterior-posterior chest compression approach. It is proposed to introduce a force/deflection boundary condition into mechanical and computer/numeric infant models. Subject to the future inclusion of loading rate/response data, a three-dimensional (force/deflection/loading rate) boundary condition will be used to provide a minimum injury threshold for potentially injurious scenarios. A number of further studies are suggested, since this paper is intended to provide a first step to developing a more sophisticated understanding of the causes of infant rib fracture. Areas of further study include specific rib fracture mechanisms, as well as the effects of age dependent characteristics, positioning and area of force application. Such additional information would allow the proposed initial boundary condition to be further refined to provide an indication of the likelihood, type and number of fractures that might be expected.

A fatal fall from a balcony? A biomechanical approach to resolving conflicting witness accounts

An adult male was found below a third floor balcony having sustained fatal head injuries. An account provided by a witness described how the deceased had been in high spirits and had engaged in swinging from the third floor balcony rail in an attempt to swing onto a lower second floor balcony and whilst doing so had lost his grip and fallen (10.67 metres) to the ground below. A conflicting account was provided, some weeks later, by a second witness, who claimed to have observed an argument between two men on a third floor balcony, during which one had vigorously pushed the other over the balcony rail. The push, it was alleged, caused the man to move very quickly over the balcony rail and fall in an 'upturned crucifix' position to the ground. This paper describes a series of biomechanical experiments, conducted on a reconstruction of the third floor balcony and the second floor balcony rail, during which a volunteer was subjected to the two fall scenarios, in an attempt to resolve the conflicting witness accounts. Analysis of human movement was performed using a 3-D motion analysis system, markers were placed at the volunteer's key joint centres and were tracked to determine physical parameters. The parameter values were used to calculate what dynamic movements may have occurred had the volunteer been allowed to fall, not just a distance equivalent to the lower balcony rail but a greater distance, equivalent to that between the balcony and the ground. Calculations indicate that during the hanging-fall scenario a range of body rotation was produced between 159 degrees and 249 degrees, that is, an upturned head-first body orientation, consistent with that required to produce the described injuries and consistent with the description provided by the first witness. The push-fall scenario, however, produced a greater estimated body rotation of between 329 degrees and 530 degrees, equal to the body rotating, from the point of free-fall to the moment of impact, between almost 1 and 1.5 times. This was consistent with the described injuries but inconsistent with the description provided by the second witness. It was therefore concluded that although both the accidental and inflicted-push scenarios could produce a body orientation consistent with the reported injuries, only the accidental scenario produced a fall which could be described as an 'upturned crucifix', since the push scenario produced a significantly greater body rotation. The witness who alleged that the deceased had been pushed later retracted his statement.

Development of a simulation system for performing in situ surface tests to assess the potential severity of head impacts from alleged childhood short falls

There is considerable debate in the medical literature surrounding the issue of fatal child head injuries being caused by short falls. When reviewing a case history a medical expert will form an opinion of the likely cause of an injury based on his/her knowledge of the literature, training and experience of similar cases. The severity of an injury is determined by the age of the victim, fall height, body impact site and the impact surface. A medical expert, when forming an opinion, is invariably assisted by a description of the scene or scene photographs and assumes the mechanical response of the floor conforms in the same way to "similar" surfaces. The impact response characteristics of the entire surface mixture is critically important when considering the potential for head injury to a child due to a short fall. However, at present during an investigation, the response of a surface to a head impact remains an unknown, since a simple description of, or cursory glance at, a floor surface is insufficient in determining its potential to cause injury. This paper documents the development of a simulation system for assessing the impact response, and potential to cause injury, of domestic floor surfaces during short falls. The method utilises a headform and drop tower adapted from techniques and current standards used to assess the potential for childhood head injuries of playground surfaces and pedestrian-bonnet impacts. The results suggest that the potential of a surface to cause head injury is dependent on the entire surface mixture, including the top surface layer (e.g. carpet and underlay), the underlying surface (wood, chipboard or concrete) and the support material (joists, supports. etc.). The results illustrate a wide range of injury potential between surface mixtures. The simulation system shows the potential to discriminate between differences in surface mixture. In conclusion, the authors suggest that in future investigations, the response of the entire surface mixture be taken into account when forming an opinion on the injury potential of short falls.

Soil factors controlling mineral N uptake by Picea engelmannii seedlings: the importance of gross NH4+ production rates

* Hydroponic studies suggest that plant nitrogen (N) demand determines the rate of mineral N uptake; however, field observations show N limitation to be widespread. Field experiments are needed to understand soil factors controlling mineral N uptake. * We planted Picea engelmannii seedlings that had initially been grown from sterilized seeds, on a recently clearcut site. We applied a hybrid isotope dilution/pulse labelling technique to compare the gross production rate, concomitantly to the plant uptake rate, of soil mineral N. We also measured mineral N concentrations, microbial N, and percent ectomycorrhizal root tips. * Gross NH4+ production rate was the most important determinant of plant uptake rate. Exploratory path analysis suggested that plant uptake was also determined by microbial N, which was, in turn, determined by soil mineral N concentrations. Percent ectomycorrhizal root tips was negatively related to gross NO3- production rate and microbial N concentrations. * We conclude that nutrient flux density is important in controlling plant uptake. Mycorrhizal colonization may alter N dynamics in the rhizosphere without affecting mineral N uptake by seedlings.

New pseudophase structure for alpha-Pu

We propose a new pseudophase crystal structure, based on an orthorhombic distortion of the diamond structure, for the ground-state alpha phase of plutonium. Electronic-structure calculations in the generalized-gradient approximation give approximately the same total energy for the two structures. Interestingly, our new pseudophase structure is the same as the gamma-Pu structure except with very different b/a and c/a ratios. We show how the contraction relative to the gamma phase, principally in the z direction, leads to an alpha-like structure in the [0,1,1] plane and reproduces the short range bonds of the alpha phase. This is an important link between two complex structures of Pu and opens new possibilities for exploring the very rich phase diagram of Pu through theoretical calculations.

Head injury and limb fracture in modern playgrounds

There were no serious head injuries in modern Cardiff municipal playgrounds with safety surfaces over five years injury surveillance. The literature suggests serious head injuries did occur before the introduction of safety surfaces.

New mechanism for the alpha to omega martensitic transformation in pure titanium

We propose a new direct mechanism for the pressure driven alpha-->omega martensitic transformation in pure titanium. A systematic algorithm enumerates all possible pathways whose energy barriers are evaluated. A new, homogeneous pathway emerges with a barrier at least 4 times lower than other pathways. The pathway is shown to be favorable in any nucleation model.

Genetic diversity: frameshift mechanisms alter coding of a gene (Epstein-Barr virus LF3 gene) that contains multiple 102-base-pair direct sequence repeats

Frameshift mutations provide recognized mechanisms for changing the coding potential of an organism. Here, multiple frameshifts are identified in repetitive sequences within an Epstein-Barr virus unspliced early gene, LF3, which is associated with the viral replicative cycle and also transcriptionally expressed in many virally associated tumors. On the DNA strand encoding LF3, there are three open reading frames, only one of which contains an initiation codon. Most (>95%) of the gene consists of numerous (>20, varying with cell source) GC-rich copies of a 102-bp direct repeat (called IR 4) flanked by small unique sequences. LF3 may express a protein if its initiation and termination codons reside in the same reading frame, but this is not always the case. Frameshifting events, occurring in short runs of pyrimidines (mainly C residues) in the repeats, give rise to mutations which may provide a mechanism for escape of an LF3 function from host surveillance. Sequence studies link these frameshifts to DNA replication errors. Notably, the number of sites in LF3 at which such mutations can occur permits a very large amount of diversity in this gene. Our data also suggest a second degeneracy mechanism within the protein itself, which influences its stability and may reflect a host defense mechanism. LF3 thus provides a potentially important model for studying the quest for supremacy between a virus and its host.

Subdural haemorrhage sustained in a baby-rocker? A biomechanical approach to causation

An unconscious 8 weeks old infant was admitted to hospital and found to have bilateral, subdural and retinal haemorrhages. He died the following day. The explanation for the subdural haemorrhage put forward by his carers was that the infant had been in a baby-rocker and that the carers had seen the rocker being rocked vigorously by their 14 months old daughter on two separate occasions. This paper describes the biomechanics of an infant model in the particular baby-rocker used and determines the maximum forces generated, comparing them with the 'forces' thought to be compatible with the causation of subdural haemorrhage.

The potential and limitations of utilising head impact injury models to assess the likelihood of significant head injury in infants after a fall

The use of engineering principles in assessing head injury scenarios is of increasing significance in investigations into suspected child abuse. A fall scenario is often given as the history for a head injury to an infant. This paper addresses the basic engineering principles and factors to be considered when calculating the severity of a head impact after free-fall. The application of head injury models (HIMs) to ascertain the forces involved in childhood head injuries from impact is also discussed. Previous studies including Duhaime et al. [J. Neurosurg. 66 (1987) 409] and Nokes et al. [Forensic Sci. Int. 79 (1995) 85] have utilised HIMs for this purpose: this paper reviews those models most widely documented.The HIM currently considered the 'state-of-the-art' is the head injury criterion (HIC) and it is suggested that this model should be utilised for assessing head impact injury in child abuse cases where appropriate.

Expression of catecholaminergic mRNAs in the hyperactive mouse mutant coloboma

The SNAP-25 deficient mouse mutant coloboma (Cm/+) is an animal model for investigating the biochemical basis of locomotor hyperactivity. The spontaneous hyperactivity exhibited by coloboma is three times greater than control mice and is a direct result of the SNAP-25 deletion. SNAP-25 is a presynaptic protein that regulates exocytotic neurotransmitter release; coloboma mice express only 50% of normal protein concentrations. Previous research has determined that there is an increase in the concentration of norepinephrine but a decrease in dopamine utilization in the striatum and nucleus accumbens of coloboma mice. In situ hybridization analysis revealed that there were corresponding increases in tyrosine hydroxylase (TH) mRNA expression in noradrenergic cell bodies of the locus coeruleus of Cm/+ mice. In contrast, TH mRNA expression in substantia nigra appeared normal in the mutant mouse. alpha(2)-Adrenergic receptors are important modulators of central noradrenergic function and dopamine release. In situ hybridization data revealed that alpha(2A)-adrenergic receptor mRNA expression is upregulated in Cm/+ mice. These results suggest an underlying abnormality in noradrenergic regulation in this hyperactive mouse mutant.

A novel approach to forensic investigation: three-dimensional kinematic and kinetic motion analysis

Following a domestic incident, a five-year-old child was pronounced dead on arrival at hospital. The subsequent post-mortem examination found that the cause of death was peritonitis as a result of a rupture of the duodenum. During the police interview, the main suspect alleged that the injury occurred whilst playing a game which involved standing on the child's abdomen and chest. A reconstruction of the game was performed using 3-dimensional kinematic and kinetic motion analysis to investigate the feasibility of the statement as described by the defendant. Presented is a summary of the investigation together with a description of kinematic and kinetic methods employed.

A biomechanical reconstruction of a wound caused by a glass shard--a case report

During the course of a criminal trial, an investigating pathologist is commonly asked how much force was required to produce an injury. This subjective opinion is based on the pathologist's previous experience of dealing with wounds inflicted with similar weapons. However, in the case of stab wounds inflicted by broken glass, it is unlikely that two glass fragments would be physically similar. In the case studied, two theories were examined: that a wound resulted from a thrown glass fragment or that it had been caused as a stab injury by the glass held in the bare hand. The investigation involved quantifying the energy required for human tissue penetration, comparison of sharpness, a biomechanical analysis of throwing actions and testing of the hypothesis that if the glass shard were used as a stabbing implement it would result in a cut to the hand.The investigation utilised a scientific methodology that reduced the need for speculative (though informed) opinion from the pathologist by producing quantitative results.

Abnormal presynaptic catecholamine regulation in a hyperactive SNAP-25-deficient mouse mutant

The consequences of a reduction in the presynaptic protein, SNAP-25, were investigated to determine the neurochemical basis of the marked hyperlocomotor activity in coloboma (Cm/+) mice. SNAP-25 is part of the minimal presynaptic machinery necessary for exocytotic neurotransmitter release. Reserpine treatment was used to deplete vesicular stores of catecholamines. Coloboma mice were more sensitive to the effects of reserpine than control mice. However, presynaptic regulation of dopamine (DA) release, as assessed by low-dose apomorphine challenge, was intact. There were region-specific reductions in in vivo tyrosine hydroxylation and the DA metabolites homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the striatum and nucleus accumbens of Cm/+ mice. While hyperactivity is often associated with changes in DA concentration, norepinephrine (NE) concentration was significantly increased in the striatum and nucleus accumbens of the hyperactive mutant. The increase in NE may regulate the hyperactivity in these mice, as suggested by current hypotheses of the mechanisms underlying attention-deficit hyperactivity disorder (ADHD) and Tourette's syndrome.

Identification of incompletely processed potential carboxypeptidase E substrates from CpEfat/CpEfat mice

In an attempt to identify peptides that may be involved in the obese phenotype observed in CpEfat/CpEfat mice (deficient in Carboxypeptidase E, CpE) samples from fourteen neuroendocrine tissues in wild-type and CpEfat/CpEfat mice were obtained. Peptides were purified from these tissues and potential CpE substrate peptides were enriched using an anhydrotrypsin column that captures peptides with basic C-termini. Bound peptides were subjected to tryptic digestion and followed by liquid chromatography-mass spectrometry analysis. The relative levels of CpEfat/CpEfat versus wild-type peptides were determined by comparison of the ion intensities. Peptide ions elevated in the CpEfat/CpEfat samples were identified by targeted liquid chromatography-tandem mass spectrometry. From those ions, 27 peptides derived from known neuropeptides (including CpE substrates) were identified, together with another 25 peptides from proteins not known to be components of the neuropeptide processing pathway. The known CpE substrates identified included the recently discovered proSAAS, granin-like neuroendocrine peptide precursor that inhibits prohormone processing. The approach demonstrated the feasibility of using an affinity-based method for identifying differences in specific classes of peptides between normal and mutant mice.

Final report of the FOPE II Financing of Pediatric Education Workgroup

Some of the challenges of financing pediatric medical education are shared with all medical education; others are specific to pediatrics. The general disadvantage that funding of graduate medical education (GME) is linked to reimbursement for clinical care has uniquely negative consequences for freestanding children's hospitals because they therefore receive little Medicare GME support. This represents both a competitive disadvantage for such hospitals and an aggregate federal underinvestment in children's health care that now amounts to billions of dollars. The need to subsidize medical student and subspecialty education with clinical practice revenue jeopardizes both activities in pediatric departments already burdened by inadequate reimbursement for children's health care and the extra costs of ambulatory care. The challenges of funding are complicated by rising costs as curriculum expands and clinical education moves to ambulatory settings. Controversies over prioritization of resources are inevitable. Solutions require specification of costs of education and a durable mechanism for building consensus within the pediatric community. Pediatrics 2000;106(suppl):1256-1269; medical student education, continuing medical education, medical subspecialties, children, pediatrics, health maintenance organizations, managed care, hospital finances, children's hospitals.

Canine TIMP-2: purification, characterization and molecular detection

Matrix metalloproteinases (MMPs), which degrade tissues in health and disease are under the control of the tissue inhibitors of MMPs, the TIMPs. TIMP-2 is particularly important for control of MMP-2 and both have been implicated in many pathological processes from arthritis to tumour invasion. This study characterized and detected TIMP-2 from canine cells; including synovial fibroblasts and three tumour-derived canine cell lines, K1, K6 and DH82. Gelatin zymography demonstrated that pro-MMP-2 is produced by synovial fibroblasts and the three cells lines. Reverse zymograms showed that all the cell sources tested secrete both TIMP-1 and TIMP-2. The 22 kDa band was purified and n-terminal amino acid sequencing showed it to be highly homologous to equine and human TIMP-2. Analysis of purified canine MMP-2 and MMP-9 showed that TIMP-2 is associated, and co-purifies with MMP-2. Polymerase chain reaction, using consensus primers, was used to detect TIMP-2 mRNA from the cell sources and proved positive in all cases. This work highlights the importance of TIMP-2 as the main inhibitor for MMP-2 and, therefore, opens the possibilities of targeting TIMP-2 for therapeutic intervention against connective amino acid tissue degradation in a range of diseases.