Multi-isotope analysis reveals that feasts in the Stonehenge environs and across Wessex drew people and animals from throughout Britain.

The great henge complexes of southern Britain are iconic monuments of the third millennium BCE, representing great feats of engineering and labor mobilization that hosted feasting events on a previously unparalleled scale. The scale of movement and the catchments that the complexes served, however, have thus far eluded understanding. Presenting the largest five-isotope system archeological dataset (87Sr/86Sr, δ34S, δ18O, δ13C, and δ15N) yet fully published, we analyze 131 pigs, the prime feasting animals, from four Late Neolithic (approximately 2800 to 2400 BCE) complexes to explore the networks that the feasts served. Because archeological evidence excludes continental contact, sources are considered only in the context of the British Isles. This analysis reveals wide-ranging origins across Britain, with few pigs raised locally. This finding demonstrates great investment of effort in transporting pigs raised elsewhere over vast distances to supply feasts and evidences the very first phase of pan-British connectivity.

In synch but not in step: Circadian clock circuits regulating plasticity in daily rhythms.

The suprachiasmatic nucleus (SCN) is a network of neural oscillators that program daily rhythms in mammalian behavior and physiology. Over the last decade much has been learned about how SCN clock neurons coordinate together in time and space to form a cohesive population. Despite this insight, much remains unknown about how SCN neurons communicate with one another to produce emergent properties of the network. Here we review the current understanding of communication among SCN clock cells and highlight a collection of formal assays where changes in SCN interactions provide for plasticity in the waveform of circadian rhythms in behavior. Future studies that pair analytical behavioral assays with modern neuroscience techniques have the potential to provide deeper insight into SCN circuit mechanisms.

A simple tool to identify elderly patients with a surgically important acute subdural haematoma.

OBJECTIVES: ASDH in the elderly is a common and increasing problem, and differs in its pathophysiology from ASDH in younger people. Admitting doctors may have difficulty identifying those elderly patients whose lesions may benefit from surgery. The objective of this study was to determine whether simple neuroradiological measurements could identify those patients, who need urgent neurosurgical referral for consideration for surgery. DESIGN: A retrospective cohort study. PARTICIPANTS: All patients aged 65 years or greater referred to Salford Royal Foundation Trust with the diagnosis of ASDH between 01/01/2008 and 31/12/2011. METHODS: The initial presenting CT brain scans were reviewed. The linear dimensions, degree of midline shift and haematoma volume (using ABC/2 method) of all scans were measured and recorded. All presenting radiology was also assessed by a consultant neurosurgeon blind to clinical and CT scan measurement data and patients were categorised as having "surgical" lesions or not. Receiver operating characteristic (ROC) curves were generated and cut point value for 100% sensitivity and specificity were tabled to assess which combination of scan parameters best predicted a "surgical" ASDH. RESULTS: 212/483 patients were considered to have a 'surgical' lesion. All 'surgical' lesions had a volume of >35ml (range 35-435), maximum thickness of ≥10mm (range 10-49) and 99% had midline shift ≥1mm (range 0-32). The best predictor of a 'surgical' lesion was a combination of maximum haematoma thickness and midline shift which offered 100% (95% CI 98.3-100) sensitivity with 83% (95% CI 77.6-87) specificity. CONCLUSION: Surgically relevant cases of ASDH in the elderly can be reliably and objectively identified by two easily performed scan measurements, haematoma thickness and midline shift. If used in routine practice, these measurements could clarify those patients who may need urgent neurosurgical referral and might avoid unnecessary transfer to neurosurgical units in this cohort.

Agreement between objective and subjective assessment of image quality in ultrasound abdominal aortic aneurism screening.

OBJECTIVE: To investigate agreement between objective and subjective assessment of image quality of ultrasound scanners used for abdominal aortic aneurysm (AAA) screening. METHODS: Nine ultrasound scanners were used to acquire longitudinal and transverse images of the abdominal aorta. 100 images were acquired per scanner from which 5 longitudinal and 5 transverse images were randomly selected. 33 practitioners scored 90 images blinded to the scanner type and subject characteristics and were required to state whether or not the images were of adequate diagnostic quality. Odds ratios were used to rank the subjective image quality of the scanners. For objective testing, three standard test objects were used to assess penetration and resolution and used to rank the scanners. RESULTS: The subjective diagnostic image quality was ten times greater for the highest ranked scanner than for the lowest ranked scanner. It was greater at depths of <5.0 cm (odds ratio, 6.69; 95% confidence interval, 3.56, 12.57) than at depths of 15.1-20.0 cm. There was a larger range of odds ratios for transverse images than for longitudinal images. No relationship was seen between subjective scanner rankings and test object scores. CONCLUSION: Large variation was seen in the image quality when evaluated both subjectively and objectively. OBJECTIVE scores did not predict subjective scanner rankings. Further work is needed to investigate the utility of both subjective and objective image quality measurements. ADVANCES IN KNOWLEDGE: Ratings of clinical image quality and image quality measured using test objects did not agree, even in the limited scenario of AAA screening.

Obstetric ultrasound education for the developing world: A learning partnership with the World Federation for Ultrasound in Medicine and Biology.

The ultrasound techniques in pregnancy e-learning project is an online resource commissioned and supported by the Education Committee of the World Federation for Ultrasound in Medicine and Biology (WFUMB). This currently consists of 10 e-learning sessions aimed at midwives and other health workers in developing countries where WFUMB has Educational Centres of Excellence, and in particular at those based mainly in rural communities at considerable distance from urban training centres. The project covers all of the basics of obstetric ultrasound such as fetal and maternal anatomy, ultrasound techniques, assessment in both early and late pregnancy, prediction of pregnancy complications and identification of common abnormalities that might interfere with delivery. The e-learning project complements a wider training programme which covers operator skills and machine controls, in order to minimise the time that the professional has to leave their rural, often poorly staffed, workplace to attend classroom-based courses in the city. Each session outlines often complex concepts using simple diagrams, interactive exercises and cine clips. Tips, tricks and best practice guidelines are provided in simple terms.

Beam characteristics of energy-matched flattening filter free beams.

PURPOSE: Flattening filter free (FFF) linear accelerators can increase treatment efficiency and plan quality. There are multiple methods of defining a FFF beam. The Elekta control system supports tuning of the delivered FFF beam energy to enable matching of the percentage depth-dose (PDD) of the flattened beam at 10 cm depth. This is compared to FFF beams where the linac control parameters are identical to those for the flattened beam. All beams were delivered on an Elekta Synergy accelerator with an Agility multi-leaf collimator installed and compared to the standard, flattened beam. The aim of this study is to compare "matched" FFF beams to both "unmatched" FFF beams and flattened beams to determine the benefits of matching beams. METHODS: For the three modes of operation 6 MV flattened, 6 MV matched FFF, 6 MV unmatched FFF, 10 MV flattened, 10 MV matched FFF, and 10 MV unmatched FFF beam profiles were obtained using a plotting tank and were measured in steps of 0.1 mm in the penumbral region. Beam penumbra was defined as the distance between the 80% and 20% of the normalized dose when the inflection points of the unflattened and flattened profiles were normalized with the central axis dose of the flattened field set as 100%. PDD data was obtained at field sizes ranging from 3 cm × 3 cm to 40 cm × 40 cm. Radiation protection measurements were additionally performed to determine the head leakage and environmental monitoring through the maze and primary barriers. RESULTS: No significant change is made to the beam penumbra for FFF beams with and without PDD matching, the maximum change in penumbra for a 10 cm × 10 cm field was within the experimental error of the study. The changes in the profile shape with increasing field size are most significant for the matched FFF beam, and both FFF beams showed less profile shape variation with increasing depth when compared to flattened beams, due to consistency in beam energy spectra across the radiation field. The PDDs of the FFF beams showed less variation with field size, the d(max) value was deeper for the matched FFF beam than the FFF beam and deeper than the flattened beam for field sizes greater than 5 cm × 5 cm. The head leakage when using the machine in FFF mode is less than half that for a flattened beam, but comparable for both FFF modes. The radiation protection dose-rate measurements show an increase of instantaneous dose-rates when operating the machines in FFF mode but that increase is less than the ratio of MU/min produced by the machine. CONCLUSIONS: The matching of a FFF beam to a flattened beam at a depth of 10 cm in water by increasing the FFF beam energy does not reduce any of the reported benefits of FFF beams. Conversely, there are a number of potential benefits resulting from matching the FFF beam; the depth of maximum dose is deeper, the out of field dose is potentially reduced, and the beam quality and penetration more closely resembles the flattened beams currently used in clinical practice, making dose distributions in water more alike. Highlighted in this work is the fact that some conventional specifications and methods for measurement of beam parameters such as penumbra are not relevant and further work is required to address this situation with respect to "matched" FFF beams and to determine methods of measurement that are not reliant on an associated flattened beam.

Binding of local anaesthetics to the lipid emulsion Clinoleic™ 20%.

Lipid emulsions have been used to treat cardiovascular collapse due to local anaesthetic toxicity. However, there are few data available on the comparative efficiency of the partitioning properties of available lipid emulsions in clinical use. This in vitro study compared the buffering properties of the lipid emulsions Clinoleic™ 20% (Baxter, Old Toongabbie, NSW) and Intralipid® 20% (Fresenius Kabi, Pymble, NSW) using both bupivacaine (Marcain® 0.5%, AstraZeneca, North Ryde, NSW) and ropivacaine (Naropin® 1%, AstraZeneca, North Ryde, NSW). The concentration of anaesthetic in buffer before and after mixing with lipid was quantified using chromatographic analysis. Bupivacaine was more effectively bound by the lipid agents, with a 40% reduction in initial concentration. Ropivacaine demonstrated a 20% reduction in concentration with the addition of lipid agents. Importantly, there was no significant difference between Intralipid and Clinoleic in terms of their buffering behaviour, suggesting equivalent binding efficacy.

Mobility, mortality, and the middle ages: identification of migrant individuals in a 14th century black death cemetery population.

Mobility and migration patterns of groups and individuals have long been a topic of interest to archaeologists, used for broad explanatory models of cultural change as well as illustrations of historical particularism. The 14th century AD was a tumultuous period of history in Britain, with severely erratic weather patterns, the Great Famine of 1315-1322, the Scottish Wars of Independence, and the Hundred Years' War providing additional migration pressures to the ordinary economic issues drawing individuals to their capital under more stable conditions. East Smithfield Black Death Cemetery (Royal Mint) had a documented use period of only 2 years (AD 1348-1350), providing a precise historical context (∼50 years) for data. Adults (n = 30) from the East Smithfield site were sampled for strontium and oxygen stable isotope analyses of tooth enamel. Five individuals were demonstrated to be statistical outliers through the combined strontium and oxygen isotope data. Potential origins for migrants ranged from London's surrounding hinterlands to distant portions of northern and western Britain. Historic food sourcing practices for London were found to be an important factor for consideration in a broader than expected (87) Sr/(86) Sr range reflected in a comparison of enamel samples from three London datasets. The pooled dataset demonstrated a high level of consistency between site data, divergent from the geologically predicted range. We argue that this supports the premise that isotope data in human populations must be approached as a complex interaction between behavior and environment and thus should be interpreted cautiously with the aid of alternate lines of evidence.

Monte Carlo modelling of diode detectors for small field MV photon dosimetry: detector model simplification and the sensitivity of correction factors to source parameterization.

The goal of this work was to examine the use of simplified diode detector models within a recently proposed Monte Carlo (MC) based small field dosimetry formalism and to investigate the influence of electron source parameterization has on MC calculated correction factors. BEAMnrc was used to model Varian 6 MV jaw-collimated square field sizes down to 0.5 cm. The IBA stereotactic field diode (SFD), PTW T60016 (shielded) and PTW T60017 (un-shielded) diodes were modelled in DOSRZnrc and isocentric output ratios (OR(fclin)(detMC)) calculated at depths of d = 1.5, 5.0 and 10.0 cm. Simplified detector models were then tested by evaluating the percent difference in (OR(fclin)(detMC)) between the simplified and complete detector models. The influence of active volume dimension on simulated output ratio and response factor was also investigated. The sensitivity of each MC calculated replacement correction factor (k(fclin,fmsr)(Qclin,Qmsr)), as a function of electron FWHM between 0.100 and 0.150 cm and energy between 5.5 and 6.5 MeV, was investigated for the same set of small field sizes using the simplified detector models. The SFD diode can be approximated simply as a silicon chip in water, the T60016 shielded diode can be modelled as a chip in water plus the entire shielding geometry and the T60017 unshielded diode as a chip in water plus the filter plate located upstream. The detector-specific (k(fclin,fmsr)(Qclin,Qmsr)), required to correct measured output ratios using the SFD, T60016 and T60017 diode detectors are insensitive to incident electron energy between 5.5 and 6.5 MeV and spot size variation between FWHM = 0.100 and 0.150 cm. Three general conclusions come out of this work: (1) detector models can be simplified to produce OR(fclin)(detMC) to within 1.0% of those calculated using the complete geometry, where typically not only the silicon chip, but also any high density components close to the chip, such as scattering plates or shielding material is necessary to be included in the model, (2) diode detectors of smaller active radius require less of a correction and (3) (k(fclin,fmsr)(Qclin,Qmsr)) is insensitive to the incident the electron energy and spot size variations investigated. Therefore, simplified detector models can be used with acceptable accuracy within the recently proposed small field dosimetry formalism.

The early and mid-term fate of the axillary artery following axillary artery cut-down and cardiac catheterization in infants and young children.

OBJECTIVES: To study the early and mid-term vascular complications of axillary artery catheterization in children <2 years by clinical and ultrasound examination. BACKGROUND: Femoral arterial access for cardiac catheterization in young children is associated with significant morbidity. Early complications of axillary artery catheterization have been reported but no long-term vascular follow-up data are available. METHODS: Prospective case-control study using standard vascular ultrasound techniques to examine the upper limbs in study participants (n = 10). RESULTS: In total, 23% of axillary artery catheterizarions (56 procedures in 54 patients) resulted in acute arterial insufficiency requiring heparin. Of the survivors under follow-up (n = 33), none had symptoms of chronic arterial insufficiency. At a median follow-up of 8 years postprocedure, three out of the ten study participants had a weak brachial pulse in the test arm but no significant difference in arm measurements. Color Doppler revealed occlusion of the axillary artery in the test arm with collateralization in three patients. The brachial peak systolic velocity (V(max)) was significantly lower in the test arm than the control arm of all the patients with a mean difference of 30 cm/sec (P = 0.007). CONCLUSION: Our study is the first to examine the long-term vascular sequelae of axillary artery catheterization using ultrasound examination and highlights the importance of careful surveillance of vascular access sites. Although axillary artery cut-down for cardiac catheterization in infants and young children does not appear to result in clinical signs of chronic arterial insufficiency, we demonstrate clear evidence of flow abnormalities on vascular ultrasound which are of uncertain long-term significance.

Dim nighttime illumination alters photoperiodic responses of hamsters through the intergeniculate leaflet and other photic pathways.

In mammals, light entrains the central pacemaker within the suprachiasmatic nucleus (SCN) through both a direct neuronal projection from the retina and an indirect projection from the intergeniculate leaflet (IGL) of the thalamus. Although light comparable in intensity to moonlight is minimally effective at resetting the phase of the circadian clock, dimly lit and completely dark nights are nevertheless perceived differentially by the circadian system, even when nighttime illumination is below putative thresholds for phase resetting. Under a variety of experimental paradigms, dim nighttime illumination exerts effects that may be characterized as enhancing the plasticity of circadian entrainment. For example, relative to completely dark nights, dimly lit nights accelerate development of photoperiodic responses of Siberian hamsters transferred from summer to winter day lengths. Here we assess the neural pathways underlying this response by testing whether IGL lesions eliminate the effects of dim nighttime illumination under short day lengths. Consistent with previous work, dimly lit nights facilitated the expansion of activity duration under short day lengths. Ablation of the IGL, moreover, did not influence photoperiodic responses in animals held under completely dark nights. However, among animals that were provided dimly lit nights, IGL lesions prevented the short-day typical expansion of activity duration as well as the seasonally appropriate gonadal regression and reduction in body weight. Thus, the present data indicate that the IGL plays a central role in mediating the facilitative effects of dim nighttime illumination under short day lengths, but in the absence of the IGL, dim light at night influences photoperiodic responses through residual photic pathways.

Trauma systems: models of prehospital and inhospital care.

INTRODUCTION: The organization of trauma care has different perspectives that depend on regional aspects. Among these, geographical peculiarities, historical developments regarding development of medical subspecialties and resident education appear to be the most relevant factors. METHODS: We performed a structured literature search on PubMed. RESULTS AND CONCLUSION: This manuscript deals with the differences of several trauma systems in certain European countries, the USA and Australia. It aims to provide an overview of the peculiarities and influences of these systems on the clinical management. However, the effect of differences in organization in different countries on patient outcome is difficult to assess. There appears to be consensus on the fact that structured treatment for acute trauma care is beneficial for trauma patients. Thus, any kind of organization contributes to improved patient outcome.

Implementing a newly proposed Monte Carlo based small field dosimetry formalism for a comprehensive set of diode detectors.

PURPOSE: The goal of this work was to implement a recently proposed small field dosimetry formalism [Alfonso et al., Med. Phys. 35(12), 5179-5186 (2008)] for a comprehensive set of diode detectors and provide the required Monte Carlo generated factors to correct measurement. METHODS: Jaw collimated square small field sizes of side 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, and 3.0 cm normalized to a reference field of 5.0 cm × 5.0 cm were used throughout this study. Initial linac modeling was performed with electron source parameters at 6.0, 6.1, and 6.2 MeV with the Gaussian FWHM decreased in steps of 0.010 cm from 0.150 to 0.100 cm. DOSRZnrc was used to develop models of the IBA stereotactic field diode (SFD) as well as the PTW T60008, T60012, T60016, and T60017 field diodes. Simulations were run and isocentric, detector specific, output ratios (OR(det)) calculated at depths of 1.5, 5.0, and 10.0 cm. This was performed using the following source parameter subset: 6.1 and 6.2 MeV with a FWHM = 0.100, 0.110, and 0.120 cm. The source parameters were finalized by comparing experimental detector specific output ratios with simulation. Simulations were then run with the active volume and surrounding materials set to water and the replacement correction factors calculated according to the newly proposed formalism. RESULTS: In all cases, the experimental field size widths (at the 50% level) were found to be smaller than the nominal, and therefore, the simulated field sizes were adjusted accordingly. At a FWHM = 0.150 cm simulation produced penumbral widths that were too broad. The fit improved as the FWHM was decreased, yet for all but the smallest field size worsened again at a FWHM = 0.100 cm. The simulated OR(det) were found to be greater than, equivalent to and less than experiment for spot size FWHM = 0.100, 0.110, and 0.120 cm, respectively. This is due to the change in source occlusion as a function of FWHM and field size. The corrections required for the 0.5 cm field size were 0.95 (± 1.0%) for the SFD, T60012 and T60017 diodes and 0.90 (± 1.0%) for the T60008 and T60016 diodes-indicating measured output ratios to be 5% and 10% high, respectively. Our results also revealed the correction factors to be the same within statistical variation at all depths considered. CONCLUSIONS: A number of general conclusions are evident: (1) small field OR(det) are very sensitive to the simulated source parameters, and therefore, rigorous Monte Carlo linac model commissioning, with respect to measurement, must be pursued prior to use, (2) backscattered dose to the monitor chamber should be included in simulated OR(det) calculations, (3) the corrections required for diode detectors are design dependent and therefore detailed detector modeling is required, and (4) the reported detector specific correction factors may be applied to experimental small field OR(det) consistent with those presented here.

Reproducibility of ultrasound measurement of the abdominal aorta.

BACKGROUND: Abdominal aortic aneurysm (AAA) screening and surveillance programmes use ultrasound imaging to measure the anteroposterior (AP) diameter of the infrarenal aorta. The aim of this study was to examine potential observer bias and variability in ultrasound measurements. METHODS: Studies were identified for review via a MEDLINE database search (1966-2009). References supplied in accessed papers were also checked for potential relevance. Consistent search terminology, and inclusion and exclusion criteria were used to ensure quality of data. Nine papers were available to review. RESULTS: Variation in intraobserver repeatability and interobserver reproducibility was identified. Six studies reported intraobserver repeatability coefficients for AP aortic diameter measurements of 1·6-4·4 mm. These were below the 5-mm level regarded as acceptable by the UK and USA AAA screening programmes. Five studies had interobserver reproducibility below the level of 5 mm. Four studies, however, reported poor reproducibility (range from -2 to +5·2 to -10·5 to +10·4); these differences may have had a significant clinical impact on screening and surveillance. CONCLUSION: The studies used different methodologies with no standardized measurement techniques. Measurements were taken by observers from different medical disciplines of varying grade and levels of training. Standard training and formal quality assurance of ultrasound measurements are important components of an effective AAA screening programme.

Electroporation of cells using EM induction of ac fields by a magnetic stimulator.

This paper describes a method of effectively electroporating mammalian cell membranes with pulsed alternating-current (ac) electric fields at field strengths of 30-160 kV m(-1). Although many in vivo electroporation protocols entail applying square wave or monotonically decreasing pulses via needles or electrode plates, relatively few have explored the use of pulsed ac fields. Following our previous study, which established the effectiveness of ac fields for electroporating cell membranes, a primary/secondary coil system was constructed to produce sufficiently strong electric fields by electromagnetic induction. The primary coil was formed from the applicator of an established transcranial magnetic stimulation (TMS) system, while the secondary coil was a purpose-built device of a design which could eventually be implanted into tissue. The effects of field strength, pulse interval and cumulative exposure time were investigated using microscopy and flow cytometry. Results from experiments on concentrated cell suspensions showed an optimized electroporation efficiency of around 50%, demonstrating that electroporation can be practicably achieved by inducing such pulsed ac fields. This finding confirms the possibility of a wide range of in vivo applications based on magnetically coupled ac electroporation.

Central ray deficiency with extensive syndactyly: a dilemma for classification.

Split Hand Foot Malformation (SHFM) (cleft hand/foot, central ray deficiency) is a complex, highly variable anomaly involving the hands and/or feet. A clinical epidemiologic study of split hand/foot (central ray deficiency) of the Manitoba population identified a subset of patients who did not present with either typical or atypical split hand. Clinically, some patients presented with "mitten hand" syndactyly; the deficiency was not recognized before imaging. In this paper, we identify additional similarly affected literature cases, review existing classifications of split hand and syndactyly and attempt to classify these patients. This group presents a challenge for classification and genetic counseling. General classifications permit inclusion of patients with diverse phenotypes; however, details are overlooked. Osseous fusions and disorganization of osseous components complicate classification. Many of these patients had findings that overlapped different subtypes within existing classifications. This cohort highlights the importance of imaging patients with distal limb anomalies. An effective classification scheme should include relevant clinical and radiographic findings in order to assist clinicians following these patients.

Measurement of the efficiency of cell membrane electroporation using pulsed ac fields.

Electroporation is a long-established technique used to deliver molecules to cells. Most in vivo electroporation protocols entail applying square-wave, or monotonically-decreasing pulses but relatively few have explored the use of pulsed ac fields. This study measures the efficiency of electroporation in human kidney embryonal cells, using pulsed ac electric fields of peak amplitude 30-200 kV m(-1). The results indicate that optimum electroporation efficiencies of up to 70% can be achieved using pulses at frequencies of 20-160 kHz. Increasing the field strength results in higher electroporation efficiency, but also increases cell kill. This study confirms that efficient electroporation may be achieved using pulsed ac fields. This finding raises the possibility of a wider range of clinical and laboratory applications based on ac technology and avoiding the use of invasive needle electrodes.

Can ultrasound propagate in the joint space of a human knee?

A large body of evidence supports the principle that the use of low-intensity pulsed ultrasound with a frequency of 1.5 MHz can reduce fracture healing time. It is hypothesized that similar therapeutic benefits may be achieved in damaged articular cartilage. This study looks specifically at a 22-mm circular ultrasound transducer delivering ultrasound with a frequency of 1.5 MHz. A human cadaver knee was imaged using CT, the resulting images were used to help map a number of hydrophone positions in the joint from which measurements were taken. The experimental results suggest that at best there is a 30-mm window in which to place the ultrasound transducer for ultrasound to propagate through the joint space. In terms of a clinical device delivering an I(SATA) of 30 mW cm(-2) to anterior regions of the joint, the I(SATA) in posterior regions will at best be in the region of 10 mW cm(-2). The clinical implications of this are not known and require further investigation.