Modular prosthetic reconstruction for primary bone tumours of the distal tibia in ten patients

BACKGROUND: Below-knee amputation (BKA) is the safest treatment for benign aggressive and malignant bone tumours of the distal tibia, yielding good oncological and functional results. However, in selected patients where limb salvage is feasible and amputation unacceptable to the patient, limb salvage using a distal tibial replacement (DTR) can be considered. This study aims to present the oncological and functional results of the use of the latter treatment method in our unit. METHODS: A retrospective folder review was performed for all ten patients who received a modular DTR between 1 January 2005 and 31 January 2019 for a primary bone tumour, either benign aggressive or malignant. Six were female and the mean age was 31 (12-75) years. There were five patients with giant cell tumour of bone, four with osteosarcoma and one with a low-grade chondrosarcoma. The patients with osteosarcoma had neoadjuvant chemotherapy before surgery. Function was assessed by the Musculoskeletal Tumor Society (MSTS) score. RESULTS: Two patients had local recurrence treated with a BKA and one other patient died of metastases three years postoperatively. At a mean follow-up of three years, the remaining eight patients had a mean MSTS score of 83% (67-93%). There were no radiological signs of loosening, and no revision surgeries. CONCLUSION: Endoprosthetic replacement of the distal tibia for primary bone tumours can be a safe treatment option in very selected cases. Level of evidence: Level 4

Rydberg Series Excitation of a Single Trapped ^{40}Ca^{+} Ion for Precision Measurements and Principal Quantum Number Scalings

A complete set of spectroscopic data is indispensable when using Rydberg states of trapped ions for quantum information processing. We carried out Rydberg series spectroscopy for nS_{1/2} states with 38≤n≤65 and for nD_{5/2} states with 37≤n≤50 on a single trapped ^{40}Ca^{+} ion. We determined the ionization energy of 2 870 575.582(15) GHz, 60 times more accurately as compared to the accepted value and contradicting it by 7.5 standard deviations. We confirm quantum defect values of δ_{S_{1/2}}=1.802 995(5) and δ_{D_{5/2}}=0.626 888(9) for nS_{1/2} and nD_{5/2} states, respectively, which allow for unambiguous addressing of Rydberg levels of Ca^{+} ions. Our measurements confirm Rydberg ion scaling properties, e.g., for blackbody induced ionization, linewidths and excitation strengths.

Erratum: Fast Domain Wall Motion Governed by Topology and Œrsted Fields in Cylindrical Magnetic Nanowires [Phys. Rev. Lett. 123, 217201 (2019)]

This corrects the article DOI: 10.1103/PhysRevLett.123.217201.

PROMs as an intervention – a randomised controlled study

Issue

Patient-Reported Outcome Measures (PROMs) are becoming part of the patient journey and are increasingly used as a mechanism to reward quality and to indicate the 'value' of the health care provided. However, only in rare cases, PROMs are not only applied to measure quality but used as a basis for medical intervention.

Description of the problem

Digitisation and patient-centred care are of major importance to highlight quality deficiencies and to promote transparency of patient pathways. However, there is little evidence on how to use the patient's feedback to transform the patient journey and to improve health outcomes. Additionally, there is rare information on scientifically tested or elaborated threshold values that could be applied to trigger an intervention in case of critical recovery. The patient's reaction to such interventions or alerts is unknown, although it promotes health literacy and could support cross-sectoral care and better health outcomes.

Results

In our two-arm RCT, we examine the effects of PROMs as an intervention and related health care costs by digitally collecting PROMs of around 10,000 patients in the field of endoprosthetics in 9 German clinics. The magnitude of the study and its digital approach suggest that the procedure can be easily transferred to other indications and countries. For the after-care period, PROM threshold alert values were defined with the support of an expert consortium of physicians, to signal critical recovery of patients in the intervention group. Study nurses are automatically alerted and post-treatment physicians informed to intervene in case of critical PROM values.

Lessons

Preliminary results suggest that patients respond positively to their contact with the study nurse and that they agree with informing their physicians about critical results. We expect an intervention of every 10th patient of the study and so far, the threshold definition seems robust in the way that it is neither too specific nor sensitive.

Key messages

PROMs used as an intervention can promote health literacy and outcomes. Development and testing of thresholds is needed.

Do patients value similar hospital characteristics and quality metrics for different treatments?

Quality competition among hospitals, induced by patients freely choosing their hospital in a price regulated market, can only be realized if quality differences between hospitals are transparent, understandable, and thus influence patients' hospital choice. We use data from ∼145,000 German patients and ∼900 hospitals for colorectal resections and knee replacements to investigate whether patients value quality and specialization when choosing their hospital. Using a random utility choice model, we estimate patients' marginal utilities, willingness to travel and change in hospital demand for quality improvements. Patients respond to service quality and specialization and thus, quality competition seems to work. Colorectal resection patients are willing to travel longer for more specialized hospitals (+9% for procedure volume, +9% for certification). Knee replacement patients travel longer for hospitals with better service quality (+6%) and higher procedure volume (+12%). However, clinical quality indicators, often difficult to access and interpret, barely play a role in patients' hospital choice. Furthermore, we find that competition on quality for colorectal resection is rather local, whereas for knee replacement we observe regional competition patterns. Consequently, future quality transparency initiatives need to entail the development and publication of understandable outcome quality indicators (e.g. patient reported outcome measures). Moreover, clinical quality indicators need to be explained and presented more intuitively.

Key messages

Quality competition among hospitals is beneficial for all participants in the health care system. Our paper reveals the quality information that is decisive in the patient’s decision making process. Accessibility and comprehensibility of quality information plays a large role in its impact on patient hospital choice. Thus, policy makers need to raise quality transparency and patient emancipation.

Risk of brainstem necrosis in pediatric patients with central nervous system malignancies after pencil beam scanning proton therapy

Background: Radiation therapy (RT) plays an important role in management of pediatric central nervous system (CNS) malignancies. Centers are increasingly utilizing pencil beam scanning proton therapy (PBS-PT). However, the risk of brainstem necrosis has not yet been reported. In this study, we evaluate the rate of brainstem necrosis in pediatric patients with CNS malignancies treated with PBS-PT.Material and methods: Pediatric patients with non-hematologic CNS malignancies treated with PBS-PT who received dose to the brainstem were included. All procedures were approved by the institutional review board. Brainstem necrosis was defined as symptomatic toxicity. The actuarial rate was analyzed by the Kaplan Meier method.Results: One hundred and sixty-six consecutive patients were reviewed. Median age was 10 years (range 0.5-21 years). Four patients (2.4%) had prior radiation. Median maximum brainstem dose in the treated course was 55.4 Gy[RBE] (range 0.15-61.4 Gy[RBE]). In patients with prior RT, cumulative median maximum brainstem dose was 98.0 Gy [RBE] (range 17.0-111.0 Gy [RBE]). Median follow up was 19.6 months (range, 2.0-63.0). One patient who had previously been treated with twice-daily radiation therapy and intrathecal (IT) methotrexate experienced brainstem necrosis. The actuarial incidence of brainstem necrosis was 0.7% at 24 months (95% CI 0.1-5.1%).Conclusion: The rate of symptomatic brainstem necrosis was extremely low after treatment with PBS-PT in this study. Further work to clarify clinical and dosimetric parameters associated with risk of brainstem necrosis after PBS-PT is needed.

Fast Domain Wall Motion Governed by Topology and Œrsted Fields in Cylindrical Magnetic Nanowires

While the usual approach to tailor the behavior of condensed matter and nanosized systems is the choice of material or finite-size or interfacial effects, topology alone may be the key. In the context of the motion of magnetic domain walls (DWs), known to suffer from dynamic instabilities with low mobilities, we report unprecedented velocities >600  m/s for DWs driven by spin-transfer torques in cylindrical nanowires made of a standard ferromagnetic material. The reason is the robust stabilization of a DW type with a specific topology by the Œrsted field associated with the current. This opens the route to the realization of predicted new physics, such as the strong coupling of DWs with spin waves above >600  m/s.

Shuttling of Rydberg Ions for Fast Entangling Operations

We introduce a scheme to entangle Rydberg ions in a linear ion crystal, using the high electric polarizability of the Rydberg electronic states in combination with mutual Coulomb coupling of ions that establishes common modes of motion. After laser initialization of ions to a superposition of ground and Rydberg states, the entanglement operation is driven purely by applying a voltage pulse that shuttles the ion crystal back and forth. This operation can achieve entanglement on a sub-μs timescale, more than 2 orders of magnitude faster than typical gate operations driven by continuous-wave lasers. Our analysis shows that the fidelity achieved with this protocol can exceed 99.9% with experimentally achievable parameters.

P4475Vasodilation- and blood pressure normalization-independent cardioprotective effects of endogenous, physical activity-induced alpha calcitonin gene-related peptide in chronic hypertension

Background

Alpha calcitonin gene-related peptide (αCGRP) is one of the strongest vasodilators and, as such, is cardioprotective in chronic hypertension when reducing the associated elevated blood pressure. However, we hypothesize that endogenous, physical activity-induced αCGRP has blood pressure independent cardioprotective effects in chronic hypertension.

Methods

Chronic hypertension was induced in WT and αCGRP−/− mice by one-kidney one-clip surgery. Chronic hypertensive WT and αCGRP−/− mice lived sedentarily or performed voluntary wheel running and were treated simultaneously with either vehicle, αCGRP or αCGRP receptor antagonist CGRP8–37. Cardiac function and tissue phenotype were evaluated echocardiographically and by ddPCR, Western blotting and histology, respectively.

Results

Blood pressure was similar among all hypertensive experimental groups. Endogenous αCGRP limited pathological cardiac remodeling and symptomatic heart failure already in sedentary, chronic hypertensive WT mice. In these mice, voluntary wheel running significantly improved cardiac tissue phenotype and function, that was abolished by CGRP8–37 treatment. In αCGRP−/− mice, αCGRP treatment, in contrast to voluntary wheel running, improved cardiac tissue phenotype and function. Specific inhibition of proliferation and myofibroblast differentiation of primary murine cardiac fibroblasts by αCGRP suggests involvement of these cells in αCGRP-mediated blunting of pathological cardiac remodeling.

Conclusion

Endogenous, physical activity-induced αCGRP has blood pressure independent cardioprotective effects and is crucial for maintaining cardiac function in chronic hypertension. Consequently, permanently inhibiting endogenous αCGRP signaling, as currently approved for migraine prophylaxis, could endanger hypertensive patients.

Acknowledgement/Funding

Swiss National Science Foundation, Novartis Foundation for Medical-biological Research

Impact of apical foreshortening on deformation measurements: a report from the EACVI-ASE Strain Standardization Task Force

Aims

Foreshortening of apical views is a common problem in echocardiography. It results in an abnormally thick false apex and a shortened left ventricular (LV) long axis. We sought to evaluate the impact of foreshortened (FS) on LV ejection fraction (LVEF) and layer-specific 2D speckle tracking based segmental (S) and global (G) longitudinal strain (LS) measurements.

Methods and results

We examined 72 participants using a GE Vivid E9 system. FS apical views were collected from an imaging window one rib-space higher than the optimal images. Ejection fraction as well as layer-specific GLS and SLS measurements were analysed by GE EchoPAC v201 and TomTec Image Arena 4.6 and compared between optimal and FS images. On average, LV long axis was 10% shorter in FS images than in optimal images. FS induced a relative change in LVEF of 3.3% and 6.9% for GE and TomTec, respectively (both, P < 0.001). Endocardial GLS was 9.0% higher with GE and 23.2% with TomTec (P < 0.001). Midwall GLS measurements were less affected (7.8% for GE and 14.1% for TomTec, respectively, both P < 0.001). Segmental strain analysis revealed that the mid-ventricular and apical segments were more affected by foreshortening, and endocardial measurements were more affected than midwall.

Conclusion

Optimal image geometry is crucial for accurate LV function assessment. Foreshorhening of apical views has a substantial impact on longitudinal strain measurements, predominantly in the apex and in the endocardial layer. Our data suggest that measuring midwall strain might therefore be the more robust approach for clinical routine use.

99mTc-Anti-Granulozyten-Antikörper (BW 250/183) zum Nachweis der Appendizitis

In der vorliegenden Studie wurde bei 50 Patienten mit Verdacht auf Appendizitis eine Immunszintigraphie mit 99mTc-markierten Anti-Granulozyten-Antikörpern (AGAk) durchgeführt. Es erfolgten Sequenzaufnahmen in der Perfusionsphase, statische Aufnahmen von Becken und Abdomen in ventraler und dorsaler Projektion 2 Stunden p.i. und eine ECT-Untersuchung. In allen Fällen wurde entweder durch Operation oder durch Langzeitbeobachtung die Diagnose gesichert. Bei 13 Patienten konnte histologisch eine akute Appendizitis gesichert werden. Von diesen Patienten hatten 11 Patienten in der Entzündungsszintigraphie einen eindeutig positiven Befund in Form einer Aktivitätsmehranreicherung an typischer Stelle gezeigt. Zwei Patienten hatten einen negativen Szintigraphiebefund. Bei den restlichen 37 untersuchten Patienten konnte eine akute Appendizitis ausgeschlossen werden. 29 dieser Patienten hatten auch ein negatives Szintigraphieergebnis, bei 3 Patienten war die Szintigraphie positiv. Bei 5 Patienten blieb die szintigraphische Diagnose unklar. Zwei dieser Patienten zeigten eine deutliche Aktivitätsanreicherung im linken Unter- und Mittelbauch. Hier konnte eine akute Divertikulitis und eine akute Peritonitis als Ursache diagnostiziert werden. Bei den restlichen drei Patienten mit unklarem Szintigraphiebefund konnte eine akute Appendizitis ebenfalls ausgeschlossen werden. Die Szintigraphie mit 99mTc-AGAk ist einfach und schnell durchführbar und den bisherigen Methoden mit Zellmarkierungen in der Diagnostik der akuten Appendizitis überlegen. Die Sensitivität für die Diagnostik der akuten Appendizitis betrug in unseren Untersuchungen 85%, die Spezifität 91%. Chronische oder vernarbte, nicht granulozytär infiltrierte Appendizitiden, bei denen jedoch meist auch keine eindeutige Operationsindikation besteht, konnten - ausgenommen zwei Fälle - mit dieser Methode nicht diagnostiziert werden.

Clinical Results of Immunoscintigraphy in a Variety of Malignant Tumors with Special Reference to Immunohistochemistry

Radioimmunoscintigraphy was performed in 52 patients with a variety of malignant tumors (colorectal, melanoma, lung, testicular, ovarian, bladder, carcinoid). Respective antibodies or their F(ab’)2 fragments against CEA (n = 23), melanoma antigen 225.28 S (n = 18), TPA (n = 4), ßHCG (n = 5) and HMFG2 (n = 2) were selected by immunohistochemistry of the primary tumor. Most patients were suspected of recurrence or of hitherto unknown distant or local metastases. Overall accuracy was 61 % (32/52). False negatives amounted to 33% (17/52). Useful additional clinical information – not available by CT, ultrasonics or serum levels of tumor markers – was obtained in 17 out of 52 patients (= 33%). From these results it seems obvious that antibodies used for radioimmunoscintigraphy should be selected on the basis of immunohistochemistry.

Predicted Rate of Secondary Malignancies Following Adjuvant Proton Versus Photon Radiation Therapy for Thymoma

PURPOSE

Thymic malignancies are the most common tumors of the anterior mediastinum. The benefit of adjuvant radiation therapy for stage II disease remains controversial, and patients treated with adjuvant radiation therapy are at risk of late complications, including radiation-induced secondary malignant neoplasms (SMNs), that may reduce the overall benefit of treatment. We assess the risk of predicted SMNs following adjuvant proton radiation therapy compared with photon radiation therapy after resection of stage II thymic malignancies to determine whether proton therapy improves the risk-benefit ratio.

METHODS AND MATERIALS

Ten consecutive patients treated with double-scattered proton beam radiation therapy (DS-PBT) were prospectively enrolled in an institutional review board-approved proton registry study. All patients were treated with DS-PBT. Intensity modulated radiation therapy (IMRT) plans for comparison were generated. SMN risk was calculated based on organ equivalent dose.

RESULTS

Patients had a median age of 65 years (range, 25-77 years), and 60% were men. All patients had stage II disease, and many had close or positive margins (60%). The median dose was 50.4 Gy (range, 50.4-54.0 Gy) in 1.8-Gy relative biological effectiveness daily fractions. No differences in target coverage were seen with DS-PBT compared with IMRT plans. Significant reductions were seen in mean and volumetric lung, heart, and esophageal doses with DS-PBT compared with IMRT plans (all P≤.01). Significant reductions in SMNs in the lung, breast, esophagus, skin, and stomach were seen with DS-PBT compared with IMRT. For patients with thymoma diagnosed at the median national age, 5 excess secondary malignancies per 100 patients would be avoided by treating them with protons instead of photons.

CONCLUSIONS

Treatment with proton therapy can achieve comparable target coverage but significantly reduced doses to critical normal structures, which can lead to fewer predicted SMNs compared with IMRT. By decreasing expected late complications, proton therapy may improve the therapeutic ratio of adjuvant radiation therapy for patients with stage II thymic malignancies.

The National Ignition Facility modular Kirkpatrick-Baez microscope

Current two-dimensional X-ray imaging at the National Ignition Facility (NIF) uses time resolved pinhole cameras with ∼10-25 μm pinholes. This method has limitations in the smallest resolvable features that can be imaged with reasonable photon statistics for inertial confinement fusion (ICF) applications. ICF sources have a broadband self-emission spectrum that causes the pinhole images obtained, through thin foil filters, to contain a similarly broadband spectrum complicating the interpretation of structure in the source. In order to study phenomena on the scale of ∼5 μm, such as dopant mix in the ICF capsule, a narrow energy band, higher spatial resolution microscope system with improved signal/noise has been developed using X-ray optics. Utilizing grazing incidence mirrors in a Kirkpatrick-Baez microscope (KBM) configuration [P. Kirkpatrick and A. V. Baez, J. Opt. Soc. Am. 38, 766-774 (1948)], an X-ray microscope has been designed and fielded on NIF with four imaging channels. The KBM has ∼12 × magnification, <8 μm resolution, and higher throughput in comparison to similar pinhole systems. The first KBM mirrors are coated with a multilayer mirror to allow a "narrow band" energy response at 10.2 keV with ΔE ∼ 3 keV. By adjusting the mirror coating only, the energy response can be matched to the future experimental requirements. Several mirror packs have been commissioned and are interchangeable in the diagnostic snout.

Post-ischaemic silencing of p66Shc reduces ischaemia/reperfusion brain injury and its expression correlates to clinical outcome in stroke

AIM

Constitutive genetic deletion of the adaptor protein p66(Shc) was shown to protect from ischaemia/reperfusion injury. Here, we aimed at understanding the molecular mechanisms underlying this effect in stroke and studied p66(Shc) gene regulation in human ischaemic stroke.

METHODS AND RESULTS

Ischaemia/reperfusion brain injury was induced by performing a transient middle cerebral artery occlusion surgery on wild-type mice. After the ischaemic episode and upon reperfusion, small interfering RNA targeting p66(Shc) was injected intravenously. We observed that post-ischaemic p66(Shc) knockdown preserved blood-brain barrier integrity that resulted in improved stroke outcome, as identified by smaller lesion volumes, decreased neurological deficits, and increased survival. Experiments on primary human brain microvascular endothelial cells demonstrated that silencing of the adaptor protein p66(Shc) preserves claudin-5 protein levels during hypoxia/reoxygenation by reducing nicotinamide adenine dinucleotide phosphate oxidase activity and reactive oxygen species production. Further, we found that in peripheral blood monocytes of acute ischaemic stroke patients p66(Shc) gene expression is transiently increased and that this increase correlates with short-term neurological outcome.

CONCLUSION

Post-ischaemic silencing of p66(Shc) upon reperfusion improves stroke outcome in mice while the expression of p66(Shc) gene correlates with short-term outcome in patients with ischaemic stroke.

An assistive decision-and-control architecture for force-sensitive hand–arm systems driven by human–machine interfaces

Fully autonomous applications of modern robotic systems are still constrained by limitations in sensory data processing, scene interpretation, and automated reasoning. However, their use as assistive devices for people with upper-limb disabilities has become possible with recent advances in “soft robotics”, that is, interaction control, physical human–robot interaction, and reflex planning. In this context, impedance and reflex-based control has generally been understood to be a promising approach to safe interaction robotics.

To create semi-autonomous assistive devices, we propose a decision-and-control architecture for hand–arm systems with “soft robotics” capabilities, which can then be used via human–machine interfaces (HMIs). We validated the functionality of our approach within the BrainGate2 clinical trial, in which an individual with tetraplegia used our architecture to control a robotic hand–arm system under neural control via a multi-electrode array implanted in the motor cortex. The neuroscience results of this research have previously been published by Hochberg et al.

In this paper we present our assistive decision-and-control architecture and demonstrate how the semi-autonomous assistive behavior can help the user. In our framework the robot is controlled through a multi-priority Cartesian impedance controller and its behavior is extended with collision detection and reflex reaction. Furthermore, virtual workspaces are added to ensure safety. On top of this we employ a decision-and-control architecture that uses sensory information available from the robotic system to evaluate the current state of task execution. Based on a set of available assistive skills, our architecture provides support in object interaction and manipulation and thereby enhances the usability of the robotic system for use with HMIs. The goal of our development is to provide an easy-to-use robotic system for people with physical disabilities and thereby enable them to perform simple tasks of daily living. In an exemplary real-world task, the participant was able to serve herself a beverage autonomously for the first time since her brainstem stroke, which she suffered approximately 14 years prior to this research.

[Optic neuropathy after retrobulbar neuritis in multiple sclerosis: are optical coherence tomography and magnetic resonance imaging useful and necessary follow-up parameters?]

BACKGROUND

This study evaluated whether progressive optic neuropathy (ON) is commonly found after retrobulbar neuritis and whether optical coherence tomography (OCT) is a useful tool for follow-up of patients with multiple sclerosis (MS).

METHODS

An observational study of 86 MS patients (currently treated with immunomodulation) with a past medical history of ON was carried out. Patients were assessed in 2010 and 2012 using the expanded disability status scale (EDSS), visual acuity, visual evoked potentials (VEP) and OCT but magnetic resonance imaging (MRI) was performed only in 2012.

RESULTS

In this study 16 men and 70 women with a mean age of 41.6 and 43.8 years, respectively, were evaluated (28 patients post bilateral and 58 patients post unilateral ON including 114 eyes post-ON and 58 eyes without previous ON). Visual acuity and VEPs improved or remained the same over the study period. Visual acuity, VEPs, retinal nerve fiber layer (RNFL) thickness and macular volume were significantly worse in eyes post-ON compared to eyes without previous ON. The RNFL significantly decreased over the study period in eyes post-ON from an average of 79.9 ± 13.3 μm to 77.0 ± 12.9 μm (p < 0.0001) and eyes without previous ON from 89.5 ± 12.9 μm to 86.0 ± 12.5 μm (p < 0.0001). The number of VEPs and RNFL thickness were significantly correlated with visual acuity in all eyes. In patients after unilateral ON the brain atrophy parameters corpus callosum index (CCI) and cella media index (CMI) were negatively correlated with the EDSS.

CONCLUSION

Initially MS often begins with an episode of ON which can be stabilized by immunomodulation. A mild progressive ON was generally detectable in this study but severe progressive ON was rarely observed. The OCT measurements showed no better correlation than the VEPs with visual acuity; however, OCT can be applied for confirmation of atypical ON. The corpus callosum index seems to be best associated with the degree of disability while, as already described in the literature, the number of T2 lesions is not well correlated with disability, probably due to the small-world network function of the brain and the position of the lesions in areas with no clinical relevance.

A Kirkpatrick-Baez microscope for the National Ignition Facility

Current pinhole x ray imaging at the National Ignition Facility (NIF) is limited in resolution and signal throughput to the detector for Inertial Confinement Fusion applications, due to the viable range of pinhole sizes (10-25 μm) that can be deployed. A higher resolution and throughput diagnostic is in development using a Kirkpatrick-Baez microscope system (KBM). The system will achieve <9 μm resolution over a 300 μm field of view with a multilayer coating operating at 10.2 keV. Presented here are the first images from the uncoated NIF KBM configuration demonstrating high resolution has been achieved across the full 300 μm field of view.

Crystallization of HfO2 in InAs/HfO2 core-shell nanowires

We report the impact of deposition parameters on the structure of HfO(2) covering InAs nanowires (NWs) being potential candidates for future field-effect transistors (FETs). Molecular beam epitaxial-grown Au-free InAs NWs were covered with HfO(2) deposited by atomic-layer deposition. The impact of the film thickness as well as the deposition temperature on the occurrence and amount of crystalline HfO(2) regions was investigated by high-resolution transmission electron microscopy (TEM) and x-ray diffraction. Compared to the deposition on planar Si substrates, the formation probability of crystalline HfO(2) on InAs NWs is significantly enhanced. Here, even 3 nm thick films deposited at 250 °C are partly crystalline. Similarly, a low deposition temperature of 125 °C does not result in completely amorphous 10 nm thick HfO(2) films, they contain monoclinic as well as orthorhombic HfO(2) nanocrystals. Combining HfO(2) and Al(2)O(3) into a laminate structure is capable of suppressing the formation of crystalline HfO2 grains.

Chirality-Induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures

The nucleation of reversed magnetic domains in Pt/Co/AlO(x) microstructures with perpendicular anisotropy was studied experimentally in the presence of an in-plane magnetic field. For large enough in-plane field, nucleation was observed preferentially at an edge of the sample normal to this field. The position at which nucleation takes place was observed to depend in a chiral way on the initial magnetization and applied field directions. A quantitative explanation of these results is proposed, based on the existence of a sizable Dzyaloshinskii-Moriya interaction in this sample. Another consequence of this interaction is that the energy of domain walls can become negative for in-plane fields smaller than the effective anisotropy field.

Endogenous α-calcitonin-gene-related peptide promotes exercise-induced, physiological heart hypertrophy in mice

AIM

It is unknown how the heart distinguishes various overloads, such as exercise or hypertension, causing either physiological or pathological hypertrophy. We hypothesize that alpha-calcitonin-gene-related peptide (αCGRP), known to be released from contracting skeletal muscles, is key at this remodelling.

METHODS

The hypertrophic effect of αCGRP was measured in vitro (cultured cardiac myocytes) and in vivo (magnetic resonance imaging) in mice. Exercise performance was assessed by determination of maximum oxygen consumption and time to exhaustion. Cardiac phenotype was defined by transcriptional analysis, cardiac histology and morphometry. Finally, we measured spontaneous activity, body fat content, blood volume, haemoglobin mass and skeletal muscle capillarization and fibre composition.

RESULTS

While αCGRP exposure yielded larger cultured cardiac myocytes, exercise-induced heart hypertrophy was completely abrogated by treatment with the peptide antagonist CGRP(8-37). Exercise performance was attenuated in αCGRP(-/-) mice or CGRP(8-37) treated wild-type mice but improved in animals with higher density of cardiac CGRP receptors (CLR-tg). Spontaneous activity, body fat content, blood volume, haemoglobin mass, muscle capillarization and fibre composition were unaffected, whereas heart index and ventricular myocyte volume were reduced in αCGRP(-/-) mice and elevated in CLR-tg. Transcriptional changes seen in αCGRP(-/-) (but not CLR-tg) hearts resembled maladaptive cardiac phenotype.

CONCLUSIONS

Alpha-calcitonin-gene-related peptide released by skeletal muscles during exercise is a hitherto unrecognized effector directing the strained heart into physiological instead of pathological adaptation. Thus, αCGRP agonists might be beneficial in heart failure patients.

Domain wall tilting in the presence of the Dzyaloshinskii-Moriya interaction in out-of-plane magnetized magnetic nanotracks

We show that the Dzyaloshinskii-Moriya interaction (DMI) can lead to a tilting of the domain wall (DW) surface in perpendicularly magnetized magnetic nanotracks when DW dynamics are driven by an easy axis magnetic field or a spin polarized current. The DW tilting affects the DW dynamics for large DMI, and the tilting relaxation time can be very large as it scales with the square of the track width. The results are well explained by an extended collective coordinate model where DMI and DW tilting are included. We propose a simple way to estimate the DMI in magnetic multilayers by measuring the dependence of the DW tilt angle on a transverse static magnetic field. These results shed light on the current induced DW tilting observed recently in Co/Ni multilayers with structural inversion asymmetry.

β-Lactam antibiotics promote bacterial mutagenesis via an RpoS-mediated reduction in replication fidelity

Regardless of their targets and modes of action, subinhibitory concentrations of antibiotics can have an impact on cell physiology and trigger a large variety of cellular responses in different bacterial species. Subinhibitory concentrations of β-lactam antibiotics cause reactive oxygen species production and induce PolIV-dependent mutagenesis in Escherichia coli. Here we show that subinhibitory concentrations of β-lactam antibiotics induce the RpoS regulon. RpoS-regulon induction is required for PolIV-dependent mutagenesis because it diminishes the control of DNA-replication fidelity by depleting MutS in E. coli, Vibrio cholerae and Pseudomonas aeruginosa. We also show that in E. coli, the reduction in mismatch-repair activity is mediated by SdsR, the RpoS-controlled small RNA. In summary, we show that mutagenesis induced by subinhibitory concentrations of antibiotics is a genetically controlled process. Because this mutagenesis can generate mutations conferring antibiotic resistance, it should be taken into consideration for the development of more efficient antimicrobial therapeutic strategies.

Sub-lethal concentrations of antibiotics are known to promote mutagenesis of bacterial DNA. Here the authors show that β-lactam antibiotics trigger mutagenesis by upregulating the stress-response protein RpoS, which downregulates mismatch-repair activity.

Maternal and perinatal outcomes among nulliparous adolescents in low- and middle-income countries: a multi-country study

OBJECTIVE

To investigate the risk of adverse pregnancy outcomes and caesarean section among adolescents in low- and middle-income countries.

DESIGN

Secondary analysis using facility-based cross-sectional data from the World Health Organization (WHO) Global Survey on Maternal and Perinatal Health.

SETTING

Twenty-three countries in Africa, Latin America, and Asia.

POPULATION

Women admitted for delivery in 363 health facilities during 2-3 months between 2004 and 2008.

METHODS

We constructed multilevel logistic regression models to estimate the effect of young maternal age on risks of adverse pregnancy outcomes.

MAIN OUTCOME MEASURES

Risk of adverse pregnancy outcomes among young mothers.

RESULTS

A total of 78 646 nulliparous mothers aged ≤24 years and their singleton infants were included in the analysis. Compared with mothers aged 20-24 years, adolescents aged 16-19 years had a significantly lower risk of caesarean section (adjusted OR 0.75, 95% CI 0.71-0.79). When the analysis was restricted to caesarean section indicated for presumed cephalopelvic disproportion, the risk of caesarean section was significantly higher among mothers aged ≤15 years (aOR 1.27, 95% CI 1.07-1.49) than among those aged 20-24 years. Higher risks of low birthweight and preterm birth were found among adolescents aged 16-19 years (aOR 1.10, 95% CI 1.03-1.17; aOR 1.16, 95% CI 1.09-1.23, respectively) and ≤15 years (aOR 1.33, 95% CI 1.14-1.54; aOR 1.56, 95% CI 1.35-1.80, respectively).

CONCLUSIONS

Adolescent girls experiencing pregnancy at a very young age (i.e. <16 years) have an increased risk of adverse pregnancy outcomes.