X-Ray Reflectivity of Ultra-Thin Diamond-Like Carbon Films

Grazing incidence x-ray reflectivity has been employed to investigate ultra-thin films of tetrahedral amorphous carbon (ta-C) grown with an S-bend filtered cathodic vacuum arc. The results indicate that x-ray reflectivity can be used as a metrological tool for thickness measurements on films as thin as 0.5 nm, which is lower than the range required for carbon overcoats for magnetic hard disks and sliders if they are to reach storage densities of 100 Gbits/in2. The density of the films was derived from the best-fit to simulated reflectivity profiles from models for the structural parameters. In such thin films, the x-rays are reflected mainly at the film substrate interface, rather than the outer surface, so that the film density is derived from analysisof the oscillations of the post-critical angle reflectivity.

Practical matters for the control of contamination in a nuclear medicine department

A practicable and safe methodology is required for the control of contamination arising due to work in nuclear medicine departments, taking account of the range of radionuclides used for diagnostic and therapeutic procedures. A method for categorising radionuclides is proposed, based on their contamination derived limits. The categories utilised are: low energy gamma, imaging gamma, high energy gamma with beta, low energy beta, high energy beta and (51)Cr. A framework for the preparation of a risk assessment for the control of contamination in a nuclear medicine department is presented. This includes assessment of the procedures performed, occupancies and workflows for the department and a review of control measures. A risk assessment should also include a contamination monitoring programme and a practicable approach is presented.

Electron Field Emission From Diamond-Like Carbon

The low electron affinity of a-C:H is related to that of diamond surfaces and is studied using a chemical bonding model. The electron field emission from hydrogenated amorphous carbon (a-C:H) and nitrogen modified a-C:H showing low turn on fields are described. Nitrogen improves the field emission, apparently by raising the Fermi level.

Properties of Tetrahedral Amorphous Carbon Deposited by A Filtered Cathodic Vacuum ARC

The properties of a highly sp3 bonded form of amorphous carbon denoted ta-C deposited from a filtered cathodic vacuum arc (FCVA) are described as a function of ion energy and deposition temperature. The sp3 fraction depends strongly on ion energy and reaches 85% at an ion energy of 100 eV. Other properties such as density and band gap vary in a similar fashion, with the optical gap reaching a maximum of 2.3 eV. These films are very smooth with area roughness of order 1 nm. The sp3 fraction falls suddenly to almost zero for deposition above about 200°C.

Energy Levels of Point Defects in Perovskite Oxides

The band structure and energy levels of defects in BaTi3, PbTiO3 and PbZrO3 are calculated and compared. The band gap of Pb(Zr,Ti)O3 varies little because the band edges are formed of Pb 6s and 6p states. The charged Ti and O vacancies are found to be shallow. Transition metal impurities at the B site are found to give rise to numerous charge states because of their high intra-atomic electron repulsion. The levels of Cr4+, Fe4+ and Co4+ lie near midgap. Ti3+ trapped electron centers become deep at higher Zr contents in PZT.

Field Emission from Tetrahedrally Bonded Amorphous Carbon

A series of tetrahedrally bonded carbon (ta-C) films have been produced using a Filtered Cathodic Vacuum Arc System. The threshold field and current densities achievable have been investigated as a function of sp3/sp2 bonding ratio and nitrogen content. Typical undoped ta-C films have a threshold field of 15–20V/μm and optimally nitrogen doped films exhibit threshold fields as low as ∼ 5 V/μm. Current densities of typically 10-4 A/cm2 at an applied field of 20V/micron were also obtained.

Properties of Diamond-Like Carbon for Thin Film Microcathodes for Field Emission Displays

Diamond-like carbon is a strong candidate for field emission microcathodes for field emission displays because of its low electron affinity and chemical inertness. The field emission properties of various types of diamond-like carbon such as a-C:H and ta-C are reviewed in the framework of a bonding model of their affinity.

Quantitative Studies of Tetrahedral Bonding in Amorphous Carbon Films Using Ultraviolet Raman Spectroscopy

The bonding in a series of unhydrogenated amorphous carbon films has been analysed quantitatively using Raman spectroscopy with ultraviolet excitation. The Raman spectra exhibit two broad Raman peaks at 1650 cm−1 and 1100 cm−1, due to sp2 and sp3 vibrational modes respectively. The former is a resonance feature associated with a large proportion of paired sp2 sites, while the latter is a weighted vibrational density-of-states for the distorted random network of sp3 sites. The position and relative intensity of the two peaks are shown to be strongly correlated with the percentage of sp3 sites in the films, providing a reliable measure of sp3 bonding which is both quantitative and non-destructive.

Band Model for Electron Emission from Diamond and Diamond-Like Carbon

The band diagram is constructed for diamond on metal and diamond-like carbon on metal emitters, from data for electron affinities, Schottky barrier heights or band offsets. For diamond, there is a large offset for the conduction band at the back-contact, causing this to be the dominant barrier for emission. Nitrogen and perhaps grain boundaries reduce this barrier by forming a depletion layer of ionised donors, which narrows the tunnelling distance. In DLC, there is little conduction band offset at the back-contact, and the dominant barrier is at the surface. Nitrogen now lowers the emission barrier by raising the bulk Fermi level and lowering the work function. Unresolved problems are also pointed out.

Electronic Structure and Surface Properties of SrBi2Ta2O9 and Related Oxides

The electronic structure of SrBi2Ta2O9 and related oxides such as SrBi2Nb2O9, Bi2WO6 and Bi3Ti4O12 have been calculated by the tight-binding method. In each case, the band gap is about 4.1 eV and the band edge states occur on the Bi-O layers and consist of mixed O p/Bi s states at the top of the valence band and Bi p states at the bottom of the conduction band. The main difference between the compounds is that Nb 5d and Ti 4d states in the Nb and Ti compounds lie lower than the Ta 6d states in the conduction band. The surface pinning levels are found to pin Schottky barriers 0.8 eV below the conduction band edge.

Deposition and Properties of Diamond-Like Carbons

We review for diamond-like carbon the various deposition methods, the deposition mechanisms of subplantation and ion-assisted addition, the characterisation methods such as Raman and electron energy loss spectroscopy, its mechanical properties and some applications as a coating material.

Theory of Electron Field Emission From Diamond And Diamond-Ldxe Carbon

It is shown that the facile electron field emission from diamond and diamond-like carbon occurs because surface groups such as C-H can produce large changes in electron affinity, so that electric fields from the anode can be focused towards unhydrogenated surface areas of high affinity, the fields ending on negative charges in an underlying depletion layer. The resulting downwards band bending creates very large fields which cause Fowler-Nordheim emission, while not exceeding the material's breakdown field, which is the highest for any solid.

Field Emission From Tetrahedrally Bonded Amorphous Carbon as a Function of Surface Treatment and Contact Material

In order to test whether field emission from tetrahedrally bonded amorphous (ta-C) is affected by the back contact material we have carried out a series of emission experiments on Filtered Cathodic Vacuum Arc (FCVA) produced ta-C films. The measurements were made on identical films of approximately 25 nm thickness which have been grown simultaneously on various substrates of different work function. For these experiments the substrates used were p-type c-Si, n-type c-Si, SnO2, tungsten, gold, lead, aluminium, molybdenum, chromium and titanium. Threshold fields for emission were generally in the range of 5–15 V/micron and showed no direct dependence on back contact material work function. Films grown on Ti and W however had much higher threshold fields in the range 30–35 V/micron and this is thought to be associated with the native oxide which was present between the back contact and the ta-C film. As grown ta-C is also known to have a 1–2 nm thick sp2 rich layer on its surface and this layer may also have some effect on field emission. The layer was etched in either an O2 or H2 plasma and both etched surfaces led to improved emission efficiency.

Doping Mechanism in Tetrahedral Amorphous Carbon

Doping in hydrogenated amorphous silicon occurs by a process of an ionised donor atom partially compensated by a charged dangling bond. The total energies of various dopant and dopant/bonding combinations are calculated for tetrahedral amorphous carbon. It is found that charged dangling bonds are less favoured because of the stronger Coulombic repulsion in ta-C. Instead the dopants can be compensated by weak bond states in the lower gap associated with odd-membered π-rings or odd-numbered π-chains. The effect is that the doping efficiency is low but there are not charged midgap recombination centres, to reduce photoconductivity or photoluminescence with doping, as occurs in a-Si:H.

A novel double mutation in FUS gene causing sporadic ALS

It has been shown that mutations in the Fused in Sarcoma gene (FUS) could explain up to 5% of cases with familial amyotrophic lateral sclerosis (ALS). Our mutation analysis of FUS in a Canadian ALS patient of Chinese origin revealed an unusual novel heterozygous double point mutation (R514S/E516V) confirming that exon 15 is a mutation hot-spot. The substitutions are in cis position to each other and affect highly conserved codons in the RGG-rich region of the FUS protein. The absence of clinical signs of ALS in the relatives of the affected carrier could indicate that this mutation is incompletely penetrant or de novo. The pathologic significance of the R514S/E516V mutation was confirmed by immunohistochemistry. FUS-positive cytoplasmic inclusions were noted in a moderate number in neurons and abundantly in glial cells in the motor cortex and the brainstem. Of interest, a significant number of neuronal and glial FUS-positive inclusions were found in the tegmentum of the brainstem. Importantly, some neurons with inclusions showed retention of the normal nuclear FUS immunostaining.

Ecological opportunity and the origin of adaptive radiations

Ecological opportunity--through entry into a new environment, the origin of a key innovation or extinction of antagonists--is widely thought to link ecological population dynamics to evolutionary diversification. The population-level processes arising from ecological opportunity are well documented under the concept of ecological release. However, there is little consensus as to how these processes promote phenotypic diversification, rapid speciation and adaptive radiation. We propose that ecological opportunity could promote adaptive radiation by generating specific changes to the selective regimes acting on natural populations, both by relaxing effective stabilizing selection and by creating conditions that ultimately generate diversifying selection. We assess theoretical and empirical evidence for these effects of ecological opportunity and review emerging phylogenetic approaches that attempt to detect the signature of ecological opportunity across geological time. Finally, we evaluate the evidence for the evolutionary effects of ecological opportunity in the diversification of Caribbean Anolis lizards. Some of the processes that could link ecological opportunity to adaptive radiation are well documented, but others remain unsupported. We suggest that more study is required to characterize the form of natural selection acting on natural populations and to better describe the relationship between ecological opportunity and speciation rates.

Long-term impact of respiratory viral infection after pediatric lung transplantation

To evaluate the epidemiology and to investigate the impact of RVI on chronic allograft rejection after pediatric lung transplantation, a retrospective study of pediatric lung transplant recipients from 2002 to 2007 was conducted. Association between RVI and continuous and categorical risk factors was assessed using Wilcoxon rank-sum tests and Fisher's exact tests, respectively. Association between risk factors and outcomes were assessed using Cox proportional hazards models. Fifty-five subjects were followed for a mean of 674 days (range 14-1790). Twenty-eight (51%) developed 51 RVI at a median of 144 days post-transplant (mean 246; range 1-1276); 41% of infections were diagnosed within 90 days. Twenty-five subjects developed 39 LRI, and eight subjects had 11 URI. Organisms recovered included rhinovirus (n = 14), adenovirus (n = 10), parainfluenza (n = 10), influenza (n = 5), and RSV (n = 4). Three subjects expired secondary to their RVI (two adenovirus, one RSV). Younger age and prior CMV infection were risks for RVI (HR 2.4 95% CI 1.1-5.3 and 17.0; 3.0-96.2, respectively). RVI was not associated with the development of chronic allograft rejection (p = 0.25) or death during the study period. RVI occurs in the majority of pediatric lung transplant recipients, but was not associated with mortality or chronic allograft rejection.

DNA detective: a review of molecular approaches to wildlife forensics

Illegal trade of wildlife is growing internationally and is worth more than USD$20 billion per year. DNA technologies are well suited to detect and provide evidence for cases of illicit wildlife trade yet many of the methods have not been verified for forensic applications and the diverse range of methods employed can be confusing for forensic practitioners. In this review, we describe the various genetic techniques used to provide evidence for wildlife cases and thereby exhibit the diversity of forensic questions that can be addressed using currently available genetic technologies. We emphasise that the genetic technologies to provide evidence for wildlife cases are already available, but that the research underpinning their use in forensics is lacking. Finally we advocate and encourage greater collaboration of forensic scientists with conservation geneticists to develop research programs for phylogenetic, phylogeography and population genetics studies to jointly benefit conservation and management of traded species and to provide a scientific basis for the development of forensic methods for the regulation and policing of wildlife trade.

Keeping Kids Smokefree: lessons learned on community participation

Community participation in program decision-making and implementation is an ideal that community and academic stakeholders aspire to in participatory research. This ideal, however, can be difficult to achieve. We describe lessons learned about community participation from a quasi-experimental trial aimed at reducing the uptake of smoking among pre-adolescents in a community with a high percentage of Māori and Pacific Island people. The intervention involves students, parents, school teachers and management, extended families and members of the wider community. A total of approximately 4000 students (and their parents) of four urban Auckland schools were enrolled in the study over 3 years. The intervention is carried out through collaborations between public health professionals, academic institutions and school personnel. In order to enhance community participation, we conclude that (i) time commitment is needed to establish long-term ongoing relationships through face-to-face communication, (ii) research team members should ideally share similar cultural and ethnic backgrounds to the target audience and have in-depth understanding of and experience in the community milieu and (iii) collaborative partnerships between academic institutions and public health services are necessary to create strength and cohesion, and assist with clear articulation of the research project mission and objectives.

Syphilis co-infection does not affect HIV disease progression

HIV and syphilis are often seen as co-infections since they share a common mode of transmission. During episodes of syphilis, CD4 counts transiently decrease and HIV viral loads increase; however, the effect of syphilis co-infection on HIV disease progression (time to AIDS or death) is unclear. We analysed prospectively collected information on 2239 persons with estimated dates of HIV seroconversion (205 [9.2%] with confirmed syphilis and 66 [2.9%] with probable syphilis) in order to determine the effect of syphilis co-infection on HIV disease progression. In multivariate models censored at highly active antiretroviral therapy (HAART) initiation or last visit, adjusting for CD4 count, age, race, gender, and hepatitis B and C status, syphilis (confirmed + probable) was not associated with increased hazard of AIDS or death (hazard ratio 0.99, 95% CI 0.73-1.33). Treating HAART as a time-varying covariate or limiting the analysis to only confirmed syphilis cases did not significantly alter the results. Despite transient changes in CD4 counts and viral loads, syphilis does not appear to affect HIV disease progression.

Clinical experience with porous tantalum cervical interbody implants in a prospective randomized controlled trial

A prospective randomized study was undertaken to evaluate the radiological appearance and clinical effectiveness of two porous tantalum (Hedrocel) implants in achieving a stable cervical interbody fusion. A prerandomization protocol was used to allocate patients to the three arms of the study: a ring implant containing autologous cancellous bone graft, a solid block implant or autologous tricortical iliac crest bone graft. Patients were followed for 2 years with plain radiological studies, SF-36, and Neck Disability Index questionnaires and neurological assessment. Early in the study the postoperative radiographs of four patients receiving Hedrocel implants showed inferior end-plate lucency raising concerns about delayed or non-fusion. Recruitment to the study was halted by the investigators to allow longer-term follow-up of the implanted patients when only 24 patients had been recruited to the study. Although fusion was subsequently noted in all patients at 12 months there was no further enrolment to the study. At 2 years the radiological and clinical outcomes of the three groups appeared comparable, but the study numbers were too small for any statistical analysis. This study highlights the difficulties that can arise when clinical caution takes precedence over objective measures of clinical progress during a study. In the absence of an independent safety monitoring committee, the investigators were under an ethical obligation to suspend recruitment to this study, until it was clear that the radiological features were not associated with poor clinical outcomes. The use of safety monitoring committees and the clarification of stopping criteria in relation to outcome measures should be considered in open randomized trials of spinal surgical techniques and implants.

Sorafenib and radiation: A promising combination in colorectal and pancreas cancer

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Background: Sorafenib inhibits both RAF kinase, a critical component of the RAS/RAF/MEK/ERK signaling pathway that controls cell proliferation, and VEGFR-2/PDGFR-beta signaling cascade, blocking tumor angiogenesis; this dual activity has great potential for radiosensitization. This study examines the effectiveness of radiation and sorafenib in a series of human colorectal and pancreatic cell lines and xenografts with differing ras mutational status. Methods: Three colorectal cell lines were selected. HT29 and SW48 are wild-type ras whilst SW480 has a mutation in codon 12 . Two pancreatic cancer cell lines were selected, Panc 03.27 is wild-type ras whilst Panc 02.03 has a mutation in codon 12. MTT assays were used to find the best drug concentration and timing to combine with radiation. Radiosensitization was assayed using clonogenic assays with either 5 or 10μg/ml sorafenib. Xenografts were established and randomized to control, sorafenib at 20mg/kg daily (5 days/week) for 3 weeks, radiation given as 2.5 Gy daily fractions (5 days/week) for 3 weeks or a combination of the two with sorafenib administered immediately after radiation Results: The MTT data suggested that sorafenib given immediately after or at least within 2 hours of radiation appeared to give the greatest growth inhibition. Sorafenib had no effect on cell survival in the colorectal cell lines but showed a modest radiosensitization, the surviving fractions at 2 Gy alone or with 5 or 10 μg/ml sorafenib were 34%, 26% and 23% (p=0.0018) in SW48 cells. In pancreatic cells, sorafenib was toxic at 10 μg/ml and reduced survival by 30% at 5 μg/ml without sensitization The endpoint in the xenograft studies was tumor growth to 2000mm3 within a period of 120 days. In SW48 tumors, the number of days to grow to 2,000 mm3 was 13.6 ± 2.2 in the control arm, 37.0 ± 21.2 in the radiation alone arm, 17.0 ± 8.2 in the sorafenib arm and100.8 ± 28.0 in the combined arm (2 of the 5 animals were ‘cured‘). The respective data in the HT29 xenografts was13.2 ± 2.1, 62.6 ± 9.8, 38.2 ± 26.5 and106.2 ± 36.2 days (3 of 5 animals were ‘cured‘. Conclusions: Sorafenib and radiation are a promising combination. Phase I studies are under development in both pancreatic and colorectal cancer at our Instittution.

No significant financial relationships to disclose.

A mechanism for low penetrance in an ALS family with a novel SOD1 deletion

BACKGROUND

About 20% of familial amyotrophic lateral sclerosis (ALS) is caused by mutations in SOD1 and is typically transmitted as an autosomal dominant trait. However, due to reduced mutation penetrance, the disease may present in a recessive or sporadic manner.

OBJECTIVE

To determine the factors responsible for the low penetrance of the SOD1 mutation.

METHODS

Twelve members of a Canadian ALS family of Filipino origin were recruited for the study. SOD1 was sequenced in the proband. SOD1 expression was assessed by real-time-PCR and immunoblotting.

RESULTS

The proband was a homozygous carrier of a novel 6 bp deletion in exon 2 (DeltaG27/P28), the pathologic significance of which was confirmed by immunohistochemistry. Eight living family members are heterozygotes and remain unaffected at ages ranging between 48 and 85 years. Haplotype analysis showed that the deletion is a single founder mutation likely common in the Cagayan province (Philippines). The low penetrance of the mutation is explained by the fact that it enhances the naturally occurring alternative splicing of exon 2 of the SOD1 mRNA, leading to reduced transcription of the mutant allele. Indeed, Western blot analysis demonstrated the low level of SOD1 protein in carriers of the DeltaG27/P28 compared to wild-type individuals or a carrier of the A4V SOD1 mutation.

CONCLUSION

The enhanced splicing of exon 2 acts as a natural knock-down of the mutant SOD1 allele in the Filipino amyotrophic lateral sclerosis (ALS) family. There is a need for careful investigation of splicing isoforms of SOD1 and other ALS genes as factors influencing the severity of disease.

Controlling the catalyst during carbon nanotube growth

We have recently been able to grow single-walled carbon nanotubes by purely thermal chemical vapour deposition (CVD) at temperatures as low as 400 degrees C. This has been achieved by separating the catalyst pre-treatment step from the growth step. In the pre-treatment step, a thin film catalyst is re-arranged into a series of nano-droplets, which are then the active catalysts. Both steps have been studied by in-situ environmental transmission electron microscopy and X-ray photoemission spectroscopy. We have also studied the catalyst yield, the weight of nanotubes grown per weight of transition metal catalyst. Using very thin layers of Fe on Al2O3 support in a remote plasma-assisted CVD, we have achieved yields of order 100,000. This may be due to control of catalyst poisoning by ensuring an etching path.

Effects of loading the unaffected limb for one session of locomotor training on laboratory measures of gait in stroke

BACKGROUND

Walking following stroke involves compensatory strategies by the unaffected leg to cope with the deficits in the hemiparetic leg. Recently, training paradigms based on the principles of task-oriented repetitive exercise have provided a valuable insight regarding the influence of restraining compensatory movements to improve motor performances. We investigated changes in the walking movements of each lower extremity after weighting the unaffected leg.

METHODS

Ten individuals early after a stroke (range: 3-7 months) who were able to walk 10 m with no aids, participated to this study. Subjects were instructed to walk on a treadmill with an external mass attached around the non affected ankle during a single session. The short-term effects on gait performance were quantified by a 3D-gait analysis system before, immediately after and 20 min after the walking technique.

FINDINGS

A one factor repeated measures model revealed that stroke participants significantly improved in walking speed (P<0.001), step length (P<0.01) and cadence (P<0.01). Weight-bearing on the paretic leg increased (P<0.01) along with kinematic modifications including greater hip and knee excursion. When the mass was removed, these adaptations were maintained 20 min later.

INTERPRETATION

Preliminary findings suggest that even brief gait training using a treadmill with a restrictive weight placed on the distal extremity of the non-hemiplegic lower limb can improve laboratory measures of gait ability in a sample of stroke subjects. Future studies must evaluate the effect of this technique in longer-term locomotor retraining.

The placebo effect and its determinants in osteoarthritis: meta-analysis of randomised controlled trials

OBJECTIVE

To examine the placebo effect and its potential determinants in the treatment of osteoarthritis (OA) via a systematic literature search of Medline, EMBASE, Scientific Citation Index, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Cochrane Library.

METHODS

Randomised placebo controlled trials in OA were included. The placebo effect was defined as the overall change from baseline in the placebo group. It was estimated as the effect size (ES; the standard mean difference between baseline and endpoint) and this was compared with the ES obtained from untreated control. ES for pain was the primary outcome. Statistical pooling was undertaken as appropriate and 95% CIs were used for comparison. Quality of trials was assessed and potential determinants of placebo effect were examined using multiple regression analysis. The partial regression coefficient (beta) was used to present the adjusted size of the association.

RESULTS

We identified 198 trials with 193 placebo groups (16 364 patients) and 14 untreated control groups (1167 patients) that met our inclusion criteria. These included a range of therapies (non-pharmacological, pharmacological and surgical treatments). Placebo was effective at relieving pain (ES 0.51, 95% CI 0.46 to 0.55 for the placebo group and 0.03, 95% CI -0.13 to 0.18 for untreated control). Placebo was also effective at improving function and stiffness. The pain-relieving effect increased when the active treatment effect (beta=0.38, p<0.001), baseline pain (0.006, p=0.014) and sample size (0.001, p=0.004) increased, and when placebo was given through injections/needles (0.144, p=0.020).

CONCLUSION

Placebo is effective in the treatment of OA, especially for pain, stiffness and self-reported function. The size of this effect is influenced by the strength of the active treatment, the baseline disease severity, the route of delivery and the sample size of the study.

Index to ring finger length ratio and the risk of osteoarthritis

OBJECTIVE

To determine the relationship between the index to ring finger (2D:4D) length ratio and the risk of knee and hip osteoarthritis (OA).

METHODS

We conducted a case-control study, in which cases with persistent symptoms and radiographic evidence of knee or hip OA were compared with controls with no symptoms and no radiographic evidence of knee or hip OA. Hand radiographs were visually classified as type 1 (index finger longer than the ring finger), type 2 (index finger equal to the ring finger), or type 3 (index finger shorter than the ring finger). The 2D:4D phalangeal and metacarpal length ratios were measured separately. The odds ratio (OR) and 95% confidence interval (95% CI) were calculated and adjusted for possible confounding factors using a logistic regression model.

RESULTS

Of 2,049 cases, 1,013 had radiographic evidence of knee OA and 995 had hip OA. Of 1,123 controls, 836 had no knee OA and 1,050 had no hip OA. The type 3 finger pattern was associated with knee OA (OR 1.94, 95% CI 1.54-2.44), and the risk was greater in women (OR 3.05, 95% CI 2.08-4.47) than in men (OR 1.45, 95% CI 1.08-1.95). There was a dose-response relationship between both 2D:4D phalangeal and metacarpal length ratios and the risk of knee OA. The risk of hip OA was inconsistent.

CONCLUSION

Compared with types 1 and 2, the type 3 "male" pattern 2D:4D length ratio is associated with OA, especially knee OA. The risk is independent of other major OA risk factors.

Strangulated stomach within a paraoesophageal hernia: a rare complication of laparoscopic Nissen fundoplication

A strangulated stomach within a paraoesophageal hernia is a rare complication following laparoscopic Nissen fundoplication. A case is presented together with a review of the clinical presentation, mechanism and diagnostic difficulties of this entity.

Radiographic assessment of the index to ring finger ratio (2D:4D) in adults

The smaller index to ring finger (2D:4D) ratio has been considered as a 'male finger pattern' and is associated with sporting ability and a number of conditions. However, the ratio may vary according to what is measured, the hand selected and the method used. This study aimed to determine: (1) which bones (phalanges, metacarpals or both) account for variation in the 2D:4D ratio; (2) whether the ratio shows right-left symmetry or relates to hand dominance; and (3) the correlation between visual classification and measured determinations of the ratio based on radiographs. Hand radiographs obtained as part of a large osteoarthritis genetic study were examined. Each hand was classified visually into three types according to the relative length of the index and ring finger: Type 1 (index longer than ring), Type 2 (index = ring) and Type 3 (index shorter than ring). For both index and ring fingers we measured (1) from base of proximal to tip of distal phalanx and (2) metacarpal length. Reproducibility of the classification and measurements were examined using kappa and intraclass correlation coefficient; symmetry between left and right hands was examined using Bland and Altman's agreement analysis; and correlation between visual classification and 2D:4D ratio data was analysed using the anova linearity test. Data were obtained from 3172 radiographs (1636 men, 1536 women; mean age 67 +/- 7.9 years, range 45-86 years). Prevalence of Type 3 hand was 61% in men and 37% in women (P < 0.001). Men had smaller 2D:4D ratios than women for phalanges (0.908 versus 0.922, P < 0.01), metacarpals (1.152 versus 1.157, P < 0.01) and the sum of phalanges plus metacarpals (1.005 versus 1.015, P < 0.01). The mean difference between right and left was -0.001 (95% limit of agreement -0.035, 0.032) for the phalangeal ratio and 0.003 (95% limit of agreement -0.051 to 0.057) for the metacarpal ratio. The 2D:4D ratio did not associate with handedness or age. There was a linear trend between the visual classification of hand type and the 2D:4D ratio data (P < 0.001). More technical difficulties (due to positioning, finger trauma, osteoarthritis) were encountered with the phalangeal ratio and visual categorization than with the metacarpal ratio: the latter could be measured in 98.7% of the study population. We concluded that measured 2D:4D ratios and visual categorization can be derived from hand radiographs. The phalanges and metacarpals both contribute to the variation in 2D:4D ratio with smaller ratios observed in men than in women. The ratio is symmetrical with only very small differences between right and left hands. Visual classification may be a useful simple tool for future epidemiological studies but is more prone to bias from positioning than direct measurement. If radiographs are used for this purpose, we recommend the metacarpal ratio with measurement of a single index hand or an average of both as it is least affected by bias from malpositioning, trauma or common joint disease.