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Imposing chirality on a physical system engenders unconventional energy flow and responses, such as the Aharonov-Bohm effect and the topological quantum Hall phase for electrons in a symmetry-breaking magnetic field. Recently, great interest has arisen in combining that principle with broken Hermiticity to explore novel topological phases and applications. Here, we report unique phononic states formed when combining the controlled breaking of time-reversal symmetry with non-Hermitian dynamics, both induced through time-modulated radiation pressure forces in small nano-optomechanical networks. We observe chiral energy flow among mechanical resonators in a synthetic dimension and Aharonov-Bohm tuning of their hybridised modes. Introducing particle-non-conserving squeezing interactions, we discover a non-Hermitian Aharonov-Bohm effect in ring-shaped networks in which mechanical quasiparticles experience parametric gain. The resulting nontrivial complex mode spectra indicate flux-tuning of squeezing, exceptional points, instabilities and unidirectional phononic amplification. This rich new phenomenology points the way to the exploration of new non-Hermitian topological bosonic phases and applications in sensing and transport that exploit spatiotemporal symmetry breaking., Included Main body and Methods (19 pages, 12 figures), in addition to the Supplementary Information document (13 pages, 5 figures)

Synthetic gauge fields can be harnessed to engineer unconventional transport and localization of energy by breaking time-reversal symmetry. Nano-optomechanical systems combine photonics with mechanics to address mechanical modes via (modulated) radiation pressure and read-out motion optically. Optomechanical cavities, such as those formed by nanofabricated strings that vibrate like strings on a guitar, allow optical tuning of the spring constant and the realization of strong effective interactions between phononic modes that imprint nonreciprocal Peierls phases – akin to the Aharonov-Bohm effect for electrons [1] . Furthermore, parametric driving induces non-Hermitian dynamics and allow the engineering of gain and loss.

Journal of Instrumentation 15(3), P03021 (2020). doi:10.1088/1748-0221/15/03/P03021, Published by Inst. of Physics, London

We establish synthetic magnetic fields for nanomechanical transport by modulating optomechanical interactions. We show that the controlled breaking of time-reversal symmetry leads to chirality in the system’s eigenmodes, transport and thermodynamics.

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg was investigated through 96 weeks in EMERALD (NCT02269917). Virologically-suppressed, HIV-1-positive treatment-experienced adults (previous non-darunavir virologic failure [VF] allowed) were randomized (2:1) to D/C/F/TAF or boosted protease inhibitor (PI) plus emtricitabine/tenofovir-disoproxil-fumarate (F/TDF) over 48 weeks. At week 52 participants in the boosted PI arm were offered switch to D/C/F/TAF (late-switch, 44 weeks D/C/F/TAF exposure). All participants were followed on D/C/F/TAF until week 96. Efficacy endpoints were percentage cumulative protocol-defined virologic rebound (PDVR; confirmed viral load [VL] ≥50 copies/mL) and VL

The JEDI (Julich Electric Dipole Investigations) (http://collaborations.fz-juelich.de/ikp/jedi/) Collaboration aims to carry out a long term project for the measurement of the permanent electric dipole moments of charged particles in a storage ring. As a proof-of-concept, the COoler SYnchrotron (COSY) was equipped with a waveguide RF Wien filter designed to operate at some harmonics of the spin precession frequency ranging from 0.1 to 2 MHz. This device maintains the corresponding ratio between the RF electric and magnetic fields necessary not to induce any beam excitation and most importantly acts as a spin flipper. In the course of 2017, the waveguide RF Wien has been successfully commissioned and tested. The ability of the device to produce a Lorentz Force compensation and to rotate the particles’ polarization vector has been verified. Driven vertical spin oscillations and vertical polarization build-up has been observed. This short article briefly discusses the results of the Lorentz force measurements at 871 kHz.

It is difficult to burn a liquid fuel inside a fluidised bed. For the first time, liquid glycerol has been burned, when continuously injected into the bottom of an electrically heated bed of alumina particles (sieved to 355–425 µm), fluidised by air. The temperature in the bed was held at 700, 800 or 900 °C; usually (U/Umf) was 2.5. The bed's depth was varied, as also were (U/Umf) and the ratio of fuel to air supplied to the bed. Measurements were made of the concentrations of CH4, O2, CO and CO2, and also of the temperature, in the freeboard well above the bed. On entering the bed, the liquid glycerol rapidly formed bubbles of vapour, which quickly decomposed thermally, yielding mostly CO and H2. These gases then mixed with the other gases in the bed. It appears that the diffusive H2 mainly burns between the fluidised particles. With the bed at 700–900 °C, no CO was detected far downstream of the bed, provided the equivalence ratio, θ, was below 0.7, i.e., with more than 43% excess air. Under these fuel-lean conditions, all the carbon in the glycerol was oxidised to CO2. However, in a more fuel-rich situation, with θ > 0.7, CO was detected well above the bed, particularly with a deeper bed, at a lower temperature and operating more fuel-rich. Thus, with the bed at 900 °C, CO was mostly oxidised inside the bed, but occasionally some CO burned on top of the bed. When a fuel-rich bed was below ≈ 850 °C, not all the CO burned in the bed. Achieving complete combustion inside a fluidised bed is partly a problem of mixing the products of glycerol's thermal decomposition with the fluidising air, which on entry exists mainly in bubbles. Consequently, increasing (U/Umf) promoted both mixing and combustion in a bed. In addition, in-bed combustion requires the bed to be sufficiently deep, hotter than ≈ 850 °C and θ to be less than a critical value. The effects of other variables are discussed.

The Hamiltonian of a linearly driven two-level system, or qubit, in the standard rotating frame contains non-commuting terms that oscillate at twice the drive frequency, $\omega$, rendering the task of analytically finding the qubit's time evolution nontrivial. The application of the rotating wave approximation (RWA), which is suitable only for drives whose amplitude, or envelope, $H_1(t)$, is small compared to $\omega$ and varies slowly on the time scale of $1/\omega$, yields a simple Hamiltonian that can be integrated relatively easily. We present a series of corrections to the RWA Hamiltonian in $1/\omega$, resulting in an effective Hamiltonian whose time evolution is accurate also for time-dependent drive envelopes in the regime of strong driving, i.e., for $|H_1(t)| \lesssim \omega$. By extending the Magnus expansion with the use of a Taylor series we introduce a method that we call the Magnus-Taylor expansion, which we use to derive a recurrence relation for computing the effective Hamiltonian. We then employ the same method to derive kick operators, which complete our theory for non-smooth drives. The time evolution generated by our kick operators and effective Hamiltonian, both of which depend explicitly on the envelope and its time derivatives, agrees with the exact time evolution at periodic points in time. For the leading Hamiltonian correction we obtain a term proportional to the first derivative of the envelope, which competes with the Bloch-Siegert shift., Comment: 30 pages, 4 figures, changes made to improve clarity, references added, published version

We probe dephasing mechanisms within a quantum network node consisting of a single nitrogen-vacancy centre electron spin that is hyperfine coupled to surrounding $^{13} \text{C}$ nuclear-spin quantum memories. Previous studies have analysed memory dephasing caused by the stochastic electron-spin reset process, which is a component of optical internode entangling protocols. Here, we find, by using dynamical decoupling techniques and exploiting phase matching conditions in the electron-nuclear dynamics, that control infidelities and quasi-static noise are the major contributors to memory dephasing induced by the entangling sequence. These insights enable us to demonstrate a 19-fold improved memory performance which is still not limited by the electron reinitialization process. We further perform pump-probe studies to investigate the spin-flip channels during the optical electron spin reset. We find that spin-flips occur via decay from the meta-stable singlet states with a branching ratio of 8(1):1:1, in contrast with previous work. These results allow us to formulate straightforward improvements to diamond-based quantum networks and similar architectures., Comment: 11 pages, 6 figures

Physical review accelerators and beams 21(4), 042002 (2018). doi:10.1103/PhysRevAccelBeams.21.042002, Published by American Physical Society, College Park, MD

An implementation of the Polynomial Chaos Expansion is introduced here as a fast solver of the equations of beam and spin motion inside an RF Wien filter. The device shall be used to search for the deuteron electric dipole moment in the COSY storage ring. The new approach is based on the stochastic Galerkin method, and it is shown that this constitutes a new and very powerful alternative to the commonly used Monte-Carlo methods., 11 pages, 8 figures, 1 table

At Ka-band frequencies, small deviations in the antenna production process result in sub-optimal performance. Classically, Monte-Carlo methods are used to quantify the influence of those tolerances. In this application, Monte-Carlo simulations are not feasible due to the high computational effort and the high number of parameters to be considered. As an alternative, we use polynomial chaos expansion to create a surrogate model using very few full-wave simulations. This model predicts the influence of the production tolerances on the performance of the antenna. Measurements confirm the results of the polynomial chaos expansion method.

This letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/$c$ bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate ($\approx 121$ kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a one standard deviation range of $\sigma = 0.21$ rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.

Intravenous drug use and sexual practices account for 60% of hepatitis C (HCV) and B (HBV) infection. Disclosing these activities can be embarrassing and reduce risk reporting, blood testing and diagnosis. In diagnosed patients, linkage to care remains a challenge. Audio-computer-assisted survey interview (Audio-CASI) was used to guide HCV and HBV infection testing in urban clinics. Risk reporting, blood testing and serology results were compared to historical controls. A patient navigator (PN) followed up blood test results and provided patients with positive serology linkage to care (LTC). Of 1932 patients surveyed, 574 (30%) were at risk for chronic viral hepatitis. A total of 254 (44.3%) patients were tested, 34 (13.5%) had serology warranting treatment evaluation, and 64% required HBV vaccination. Of 16 patients with infection, seven HCV and three HBV patients started treatment following patient LTC. Of 146 HBV-naive patients, 70 completed vaccination. About 75% and 49% of HCV antibody and HBV surface antigen-positive patients were born between 1945 and 1965. Subsequently, automated HCV testing of patients born between 1945 and 1965 was built into our hospital electronic medical records. Average monthly HCV antibody testing increased from 245 (January-June) to 1187 (July-October). Patient navigator directed LTC for HCV antibody-positive patients was 61.6%. In conclusion, audio-CASI can identify patients at risk for HCV or HBV infection and those in need of HBV vaccination in urban medical clinics. Although blood testing once a patient is identified at risk for infection needs to increase, a PN is useful to provide LTC of newly diagnosed patients.

Membranes of suspended two-dimensional materials show a large variability in mechanical properties, in part due to static and dynamic wrinkles. As a consequence, experiments typically show a multitude of nanomechanical resonance peaks, which makes an unambiguous identification of the vibrational modes difficult. Here, we probe the motion of graphene nanodrum resonators with spatial resolution using a phase-sensitive interferometer. By simultaneously visualizing the local phase and amplitude of the driven motion, we show that unexplained spectral features represent split degenerate modes. When taking these into account, the resonance frequencies up to the eighth vibrational mode agree with theory. The corresponding displacement profiles however, are remarkably different from theory, as small imperfections increasingly deform the nodal lines for the higher modes. The Brownian motion, which is used to calibrate the local displacement, exhibits a similar mode pattern. The experiments clarify the complicated dynamic behaviour of suspended two-dimensional materials, which is crucial for reproducible fabrication and applications.

This paper presents the conceptualization, design and simulation of a hybrid multi-frequency antenna system for Radio Frequency (RF) hyperthermia and Magnetic Resonance Imaging (MRI) applications with ultra-sharp hotspot. Two different bowtie antenna arrays have been designed, simulated and integrated. The first antenna array is designed as an RF coil for MR imaging. It is optimized to generate a highly homogeneous transmit equation field and is intended for 3 T MRI systems. This corresponds to a frequency of 128 MHz. The second array aims to induce heat by accumulating the electromagnetic energy at one location thereby forming a hotspot. The operating frequency of the second system is 600 MHz. The computed homogeneity of the B1+ field generated by the imaging antennas shows similar values compared to a birdcage coil at the same frequency. The size of the hotspot generated by the heating subsystem was 26 × 26 × 93mm3. The heating produced by the MR imaging antennas was negligible, compared to the RF hyperthermia applicator.

The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1 to 2 MHz at the COoler SYnchrotron COSY at J\"ulich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe., Comment: 10 pages, 10 figures, 4 tables

Sustained virologic response rates for hepatitis C virus are difficult to achieve in patients infected with human immunodeficiency virus, especially if they have other poor predictors of response. Rates of sustained virologic response for hepatitis C virus genotype 1 in patients with end stage kidney disease are lower than patients with normal renal function. We present the first case report of a co-infected African American man with end stage kidney disease, who was haemodialysis dependant, and an interferon non-responder with advanced liver fibrosis, who achieved sustained virologic response on a telaprevir-based regimen.

Objective To assess the prevalence of impairments and evaluate the relationships between impairments, activity limitations and participation restrictions in people affected by leprosy living in The Netherlands. Design A cross-sectional study. Subjects Eighty-two people affected by leprosy living in The Netherlands. Methods A postal questionnaire was performed. Impairments were inventoried with the Total Impairment Score. Activity limitations were assessed with the World Health Organization Disability Schedule II (WHODAS-II) and participation restrictions with the Impact on Participation and Autonomy (IPA) questionnaire. Results A high prevalence of impairments was found (83%), mostly in hands and feet. Activity limitations were substantial, and highest for the WHODAS-II domains "household/work" and "getting around". The severity of impairments correlated significantly with activity limitations. Eye and foot impairments independently contributed to the domains "household/work" and "getting around", explaining 34% and 40% of variance. Poor or very poor participation (IPA) was reported by 13-32% of persons, mostly in the "autonomy outdoors" and "family role" domains. These domains were associated with activity limitations and hand impairments Conclusions People affected by leprosy in The Netherlands encounter limitations in activities and participation restrictions, which are related to the severity of impairments. The high prevalence of disability suggests rehabilitation care should be considered for a substantial proportion of people affected by leprosy.

Conventional techniques, such as plain radiography and bone-scintigraphy, were used in the past to evaluate skeletal changes in patients with leprosy. More recent publications focus on radiological imaging of affected nerves, and involve advanced modalities such as Computed Tomography (CT-scan), Ultrasonography (US), and Magnetic Resonance Imaging (MRI). US and MRI can play an especially important role in the evaluation of nerve involvement in newly diagnosed patients, and also during leprosy reactions. This is important, because when nerve involvement is diagnosed in time, it may be reversible with adequate treatment. Radiological modalities can also play an important role during the followup of patients with leprosy with nerve function impairment. Skeletal and soft-tissue abnormalities occur, even after treatment. The so-called neuropathic foot is a well known consequence. Because of nerve function impairment, there is a constant risk of developing ulcers and subsequent osteomyelitis, or neuro-osteoarthropathy (Charcot foot or tarsal disintegration), which can lead to the amputation of the affected limb. Different radiological modalities can be used during the evaluation and follow-up of patients with leprosy with a neuropathic foot. With this up-to-date review, we highlight the importance and potential role of radiological imaging techniques in leprosy.

OBJECTIVES: An MRI study done in 2000 on 10 leprosy patients with neuropathic feet, without clinical complications such as ulcerations, osteomyelitis or Charcot deformities revealed abnormalities in nine patients, with degradation, interruption of subcutaneous fat and effusion/synovitis, all located in the first metatarsophalangeal (MTP) region. Since these MRI abnormalities may precede clinical complications of the foot, a follow-up study was performed. DESIGN: A new evaluation was based on a clinical examination and an MRI of the same patients who participated in the initial study. RESULTS: Four patients were lost to follow-up. Average follow-up period was 4-6 years. MRI abnormalities in the MTP 1 region in the first study were no longer visible in three patients, but were still present in two patients. In six patients new MRI findings were found, without clinical evidence of ulceration, osteomyelitis or Charcot deformity. No relationship was found between MRI findings in the MTP 1 region at the start of the study and the development of foot ulcers, callus or skin fissures in the MTP 1 region during follow-up. CONCLUSION: MRI findings of interruption and infiltration of the subcutaneous fat in leprosy patients with uncomplicated neuropathic feet do not necessarily have any clinical implication for the development of future foot problems

The objective of this publication is to provide a conceptual and simulative study of a multi-channel hybrid coil system used primarily in magnetic resonance (MR) systems for imaging as a heat inducing system for RF hyperthermia applications. A 16-channels transverse electromagnetic (TEM) coil has been designed for dual purposes as a heat inducing device and as a transceiver for magnetic resonance imaging at 400 MHz (equivalent to the protons Larmor frequency at 9.4 Tesla). Full wave and circuit-wave co-simulations have been carried out. The point specific absorption rate (SAR) pattern is computed. The 3dB width of the formed ‘hotspot’ is also evaluated and analyzed. Good matching (−28 dB) has been achieved at 400 MHz. The coupling between adjacent elements was −10.81 dB. The point SAR (with 1 W as accepted power) shows a clear sharp hotspot when the coils are used for heating. The 3dB width of the RF induced hotspot was 38 mm. The TEM RF coil used in high field MRI system, can be used as an RF hyperthermia applicator for simultaneous heating and imaging. The performance of the system shows a clear advantage compared to existing commercial system. No water bolus is required.

A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune - defined as the number of spin precessions per turn - is given by $\nu_s = \gamma G$ (gamma is the Lorentz factor, $G$ the magnetic anomaly). For 970 MeV/c deuterons coherently precessing with a frequency of ~120 kHz in the Cooler Synchrotron COSY, the spin tune is deduced from the up-down asymmetry of deuteron carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order $10^{-8}$, and to $1 \cdot 10^{-10}$ for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics: controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring., Comment: 6 pages, 6 figures

Quantitative data on leaf litter removal activity of macrozoobenthic organisms in the mangrove forests of East Africa are virtually non-existent. In the present study, litter removal activity was determined in two contrasting types of mangrove stands in Gazi Bay (Kenya). In the relatively elevated Ceriops tagal vegetation, which is only flooded during spring tides, the detritivorous snail Terebralia palustris (Linnaeus) was the major macrobenthic organism responsible for litter removal. Analysis of the delta(13)C value of the foot tissue of the snail indicated a segregation in the food consumed by individuals below and above a size of 50 mm, in agreement with the observation that only larger individuals were feeding on the leaf litter. In the low lying Rhizophora mucronata stand, which is flooded by each high tide, the crab Sesarma guttatum (H. Milne Edwards) was responsible for most of the litter removal (consumption and burial). The availability of water in the C. tagal stand, caused by tidal inundation or by rainfall, was a determining factor in the amount of litter being removed. When the stand remained dry around neap tides, the median litter removal, as a percentage of the litter fail, was only 0.8%. Under wet conditions around spring tide this percentage was much higher: 41.6% by night and 25.2% by day, respectively. These figures reflect the behaviour of T. palustris, which is inactive under dry conditions in order to avoid desiccation. Median litter removal in the R. mucronata vegetation, expressed as a percentage of the litter fall, was 40.3% by day and 21.7% by night. No relation was observed between lunar cycle and activity of the litter processing crabs. Taking into consideration differences in inundation frequency and duration, and in litter removal activity by benthic animals as related to tidal height and day/night cycles, we estimate that in this East African mangrove, on average. 11.2% and 18.6% of the fallen litter is processed by macrobenthic animals in the C. tagal and in the R. mucronata vegetation, respectively. Our results indicate that removal of fallen leaf litter in mangrove forests is not effected by benthic communities dominated by crabs only, but that activities of litter feeding snails may also be significant. [KEYWORDS: mangroves; leaf litter; litter processing; sesarmid crabs; snails; Terebralia palustris Australia; decapoda; queensland; crustacea; grapsidae; ecology]

Not only plantar pressure but also weight-bearing activity affects accumulated mechanical stress to the foot and may be related to foot ulceration. To date, activity has not been accounted for in leprosy. The purpose was to compare barefoot pressure, in-shoe pressure and daily cumulative stress between persons affected by leprosy with and without previous or current foot ulceration. Nine persons with current plantar ulceration were compared to 15 with previous and 15 without previous ulceration. Barefoot peak pressure (EMED-X), in-shoe peak pressure (Pedar-X) and daily cumulative stress (in-shoe forefoot pressure time integral×mean daily strides (Stepwatch™ Activity Monitor)) were measured. Barefoot peak pressure was increased in persons with current and previous compared to no previous foot ulceration (mean±SD=888±222 and 763±335 vs 465±262kPa, p

In the present study the tidal transport of macrolitter between the mangrove forest in Gazi bay (Kenya) and the adjacent seagrass meadows in the bay was investigated, by deploying large standing nets, which extended over the entire height of the water column, in the transition zone between both ecosystems. In addition, the presence of macrolitter on the floor ofRhizophora mucronata andCeriops tagal stands was studied. The macromaterial (>2 mm) that was collected with the nets consisted of mangrove material (26%, mostly leaf material), seagrass leaves (60%) and macroalgae (14%). Transport was bidirectional, indicating shuttle movements of the litter, driven by the opposite flow direction of flood and ebb tides. Litter from the mangrove species consisted mainly of leaves from species occurring at the outer zone of the forest,i.e., Rhizophora mucronata andSonneratia alba. This finding suggests that the complex spatial structure of the forest hampers outflow of macrolitter from the more inner parts. Consequently, this material remains trapped within the forest. The dominant presence of seagrass litter in the macromaterial transported with the tidal water, and the conspicuous and persistent presence of seagrass litter in the low lying, peripheralR. mucronata plots (but not in the more elevatedC. tagal plots) suggest that the mangrove forest of Gazi bay is the recipient of carbon and nutrients from the seagrass system. It is hypothesized that the element cycling of the inner parts of the mangrove forest proceeds as that of a rather closed system, whereas element cycling in the outer parts has conspicuous reciprocal connections with the adjacent seagrass meadows.

HIV infection is strongly associated with accelerated vascular atherosclerosis and increased cardiovascular events. The prevalence of peripheral arterial disease (PAD) in HIV infected patients is not clearly defined and the results of different reports are contradicting.To determine the prevalence of abnormal Ankle Brachial Index (ABI) and associated risk factors in HIV infected population.The ABI was measured manually using 5.0 MHz handheld Doppler probe in 173 HIV infected patients. The cohort was categorized according to the ABI measurements as; normal group (ABI 0.9 to 1.3), peripheral arterial disease (PAD) group (ABI0.9), and High ABI group (ABI1.3). Several demographic, atherosclerosis risk factors and HIV infection parameters have been evaluated as potential risk factors.Median age of the cohort was 49 years (inter-quartile ranges [IQR]: 42.5 to 54); 63.4% were males. Abnormal ABI was found in 47(27.2%) patients; twenty four (13.9%) had PAD and 23(13.3%) had high ABI. Among the risk factors evaluated, we observed that PAD group is associated with diabetes (Relative risk [RR]: 4.19; 95% confidence interval [CL]: 2.13 to 8.27; P=0.0002) and age above 49 (Relative risk [RR]: 3.96; 95% confidence interval [CL]: 1.56 to 10.0; P=0.002). However, the High ABI group was significantly associated with male gender (RR: 3.94; 95% CI: 1.23 to 12.70; P=0.009).HIV infection is associated with increased prevalence of abnormal resting ABI.

Diabetic peripheral neuropathy can cause changes in foot structures and function as well as gait abnormalities, which subsequently can lead to abnormal mechanical loading of the foot. Foot deformities, such as prominent MTHs, clawed toes and Charcot neuroarthropathy, are strongly associated with and predictive of increased plantar pressure and foot ulceration. Limited joint mobility of the foot and ankle has also been suggested to increase foot pressure and to be related to foot ulceration. Additionally, changes in quantity and quality of plantar subcutaneous fat cushioning are indicators of abnormal foot loading during walking, thereby causing high plantar foot pressure. Excessive and/or repetitive pressure applied to the plantar surface of the foot appears to be the main causative factor for development of skin breakdown. However, often, it is the combination of footwear characteristics, lifestyle factors, soft tissue characteristics, plantar foot pressures and level of physical activity that contribute to the development of foot ulceration.

Objective: To explore the relationships between perceived limitations in walking-related daily activities, walking ability (capacity), and the amount of daily walking (performance) in persons affected by leprosy and to identify their determinants. Design: A cross-sectional study. Subjects: Thirty-nine persons affected by leprosy. Methods: Perceived limitations were assessed with the World Health Organization Disability Schedule 11, domain "getting around". Walking capacity was assessed as covered distance in 6 min. Walking performance was recorded as mean strides/day with the Stepwatch(TM) 3 Activity Monitor. Potential determinants were sensory function, foot deformities, joint mobility, ankle muscle strength and co-morbidity. Results: Perceived limitations in walking-related activities were significantly correlated with walking capacity (r=-0.47; p < 0.01) but not with walking performance, although walking capacity significantly correlated with walking performance (r=0.38; p < 0.05). Various foot impairments independently contributed to reduced walking capacity and, to a lower degree, to perceived limitations in activities and performance. Conclusion: People affected by leprosy perceive limitations in walking-related activities that are determined by a reduced walking ability and the severity of foot impairments. Since perceived limitations in walking-related activities were not related to walking performance, perceived limitations are apparently weighted against the individual's needs

Although foot pressure has been reported to be increased in people affected by leprosy, studies on foot pressure and its determinants are limited. Therefore, the aim was to assess barefoot plantar foot pressure and to identify clinical determinants of increased plantar foot pressure in leprosy affected persons. Plantar pressure in both feet was assessed using the Novel EMED-X platform in 39 persons affected by leprosy. Peak pressure was determined for the total foot and four regions: hallux, metatarsal heads, midfoot and heel. Potential determinants were: age, weight, nerve function (Neuropathy Disability Score, Pressure Perception Threshold and Vibration Perception Threshold), toe and foot deformities, joint mobility, ankle muscle strength and callus. Increased peak pressure (>600 kPa) was observed in 46% of the participants. The highest peak pressure (mean) was found in the metatarsal heads region (right 549 (SD 321) kPa; left 530 (SD 298) kPa). Multilevel regression analysis showed that Neuropathy Disability Score, amputation/absorption of toes and hallux valgus independently contributed to metatarsal heads peak pressure in persons affected with leprosy. To conclude, peak pressure is increased in people affected by leprosy. The highest peak pressure is found in the forefoot region and is significantly associated to Neuropathy Disability Score, toe amputation/absorption and hallux valgus. Screening for clinical characteristics can be used to identify individual persons affected by leprosy at risk of excessive pressure. (C) 2011 Elsevier B.V. All rights reserved

Charcot neuro-osteoarthropathy is a significant problem with a rapid devastating nature. If not recognized it may lead to progressive foot deformity, ulceration or osteomyelitis, or eventually to amputation. The diagnosis is challenging, and imaging plays a pivotal role. Rapid and accurate diagnosis and early intervention is important to prevent progressive and destructive Charcot deformity of the foot. The imaging workup of the warm swollen Charcot foot is presented. The advantages and disadvantages of different imaging modalities are discussed. This review provides the consulting radiologists with tools to cautiously differentiate Charcot's neuro-osteoarthropathy from osteomyelitis. It is crucial to look beyond radiological features and integrate the location of pathology and presence of ulcer in the reading process. Because imaging plays a pivotal role in arriving at the definitive diagnosis and adequate treatment, the radiologist "makes the difference"-can be a friend or a foe.

Conventional techniques, such as plain radiography and bone-scintigraphy, were used in the past to evaluate skeletal changes in patients with leprosy. More recent publications focus on radiological imaging of affected nerves, and involve advanced modalities such as Computed Tomography (CT-scan), Ultrasonography (US), and Magnetic Resonance Imaging (MRI). US and MRI can play an especially important role in the evaluation of nerve involvement in newly diagnosed patients, and also during leprosy reactions. This is important, because when nerve involvement is diagnosed in time, it may be reversible with adequate treatment. Radiological modalities can also play an important role during the followup of patients with leprosy with nerve function impairment. Skeletal and soft-tissue abnormalities occur, even after treatment. The so-called neuropathic foot is a well known consequence. Because of nerve function impairment, there is a constant risk of developing ulcers and subsequent osteomyelitis, or neuro-osteoarthropathy (Charcot foot or tarsal disintegration), which can lead to the amputation of the affected limb. Different radiological modalities can be used during the evaluation and follow-up of patients with leprosy with a neuropathic foot. With this up-to-date review, we highlight the importance and potential role of radiological imaging techniques in leprosy.

A magnetic resonance imaging (MRI) protocol was performed in leprosy patients with a neuropathic foot and superficial ulcers and/or localized cellulitis but no clinical suspicion of osteomyelitis. The aim of the study was to determine if unsuspected osteomyelitis was present in this defined group of leprosy patients. A total of 15 neuropathic feet from 9 patients were included. Clinically and on MRI, the forefoot was predominantly affected. MRI findings of osteomyelitis were found in 4 feet. In feet with osteomyelitis, 3 had a superficial ulcer and 3 had clinical signs of localized cellulitis. A clinical diagnosis of cellulitis was confirmed on MRI in 2 feet.A striking discrepancy between clinical and MRI findings was found.This study shows that, compared with clinical evaluation, MRI is a sensitive method for the detection of unsuspected osteomyelitis in neuropathic feet with superficial ulcers and/or cellulitis. MRI findings in this group of patients may influence clinical decision making and may prevent further complications, because osteomyelitis requires more aggressive medical treatment. This preliminary communication should pave the wave for designed controlled studies so that patients with Hansen’s neuropathy may get the best medical care.

An MRI study done in 2000 on 10 leprosy patients with neuropathic feet, without clinical complications such as ulcerations, osteomyelitis or Charcot deformities revealed abnormalities in nine patients, with degradation, interruption of subcutaneous fat and effusion/synovitis, all located in the first metatarsophalangeal (MTP) region. Since these MRI abnormalities may precede clinical complications of the foot, a follow-up study was performed.A new evaluation was based on a clinical examination and an MRI of the same patients who participated in the initial study.Four patients were lost to follow-up. Average follow-up period was 4-6 years. MRI abnormalities in the MTP 1 region in the first study were no longer visible in three patients, but were still present in two patients. In six patients new MRI findings were found, without clinical evidence of ulceration, osteomyelitis or Charcot deformity. No relationship was found between MRI findings in the MTP 1 region at the start of the study and the development of foot ulcers, callus or skin fissures in the MTP 1 region during follow-up.MRI findings of interruption and infiltration of the subcutaneous fat in leprosy patients with uncomplicated neuropathic feet do not necessarily have any clinical implication for the development of future foot problems.

Infection with the human immunodeficiency virus (HIV) is still a major health problem world-wide. HIV infection has changed into a chronic infection with the chance of developing long-term complications. Vascular complications are frequently reported in the current literature. HIV and treatment by highly active antiretroviral therapy (HAART) are associated with many cardiovascular risk factors. An increased risk of arterial cardiovascular complications was found in a number of studies. However, data about the risk of venous thrombotic disease (VTE), including potentially fatal conditions as pulmonary embolism, were limited. In a systematic review of the literature, ten relevant epidemiological studies were identified that investigated the risk of venous thrombotic disease in HIV-infected patients. The incidence was increased two- to tenfold in comparison with a healthy population of the same age. However, these studies were mainly retrospective cohort studies that were prone to selection bias, confounding factors were not always mentioned and in all but three control populations were missing. An increased risk of venous thrombotic disease in HIV-infected patients could be explained by the presence of a hypercoagulable state, characterised by an increase in procoagulant factors, such as endothelial TF expression and thrombogenic properties of microparticles, and a decrease in anticoagulant factors, including AT III, HC II and the protein C pathway. Furthermore, the risk of VTE was associated with an increased risk of infections and autoimmune haemolytic anaemia, and was weakly associated with HAART. All together, quite some evidence pointed towards a relationship between HIV infection and venous thrombotic disease, but the association still needs to be established in properly designed epidemiological studies.

This study was undertaken to analyze MRI findings in leprosy patients with neuropathic feet, which are suspected of having osteomyelitis. As far as we know, there is no literature concerning osteomyelitis and MRI in neuropathic leprosy feet at present. Therefore, we have included MRI examination of 18 events of suspected osteomyelitis in 12 leprosy patients. All patients with long-standing neuropathic foot problems were clinically suspected of having osteomyelitis. All patients underwent the MRI protocol with the inclusion of Two Point Dixon Chemical Shift Imaging as a fat-suppression sequence. For the MRI evaluation, we used signs that are described in literature for detecting osteomyelitis in diabetic feet. The primary MRI signs were positive in 17 of 18 patients. The secondary MRI signs were positive in 100% of the patients. Our results show that MRI with the use of Two Point Dixon Chemical Shift Imaging is a promising diagnostic modality to detect osteomyelitis in the presence of neurosteoarthropathic changes in patients with leprosy. Whenever available, MRI could play an important role in detecting osteomyelitis in leprosy patients with long-standing neuropathic feet.