Phase offset method of ptychographic contrast reversal correction

The contrast transfer function of direct ptychography methods such as the single side band (SSB) method are single signed, yet these methods still sometimes exhibit contrast reversals, most often where the projected potentials are strong. In thicker samples central focusing often provides the best ptychographic contrast as this leads to defocus variations within the sample canceling out. However focusing away from the entrance surface is often undesirable as this degrades the annular dark field (ADF) signal. Here we discuss how phase wrap asymptotes in the frequency response of SSB ptychography give rise to contrast reversals, without the need for dynamical scattering, and how these can be counteracted by manipulating the phases such that the asymptotes are either shifted to higher frequencies or damped via amplitude modulation. This is what enables post collection defocus correction of contrast reversals. However, the phase offset method of counteracting contrast reversals we introduce here is generally found to be superior to post collection application of defocus, with greater reliability and generally stronger contrast. Importantly, the phase offset method also works for thin and thick samples where central focusing does not. Finally, the independence of the method from focus is useful for optical sectioning involving ptychography, improving interpretability by better disentangling the effects of strong potentials and focus.

Reliable phase quantification in focused probe electron ptychography of thin materials

Electron ptychography provides highly sensitive, dose efficient phase images which can be corrected for aberrations after the data has been acquired. This is crucial when very precise quantification is required, such as with sensitivity to charge transfer due to bonding. Drift can now be essentially eliminated as a major impediment to focused probe ptychography, which benefits from the availability of easily interpretable simultaneous Z-contrast imaging. However challenges have remained when quantifying the ptychographic phases of atomic sites. The phase response of a single atom has a negative halo which can cause atoms to reduce in phase when brought closer together. When unaccounted for, as in integrating methods of quantification, this effect can completely obscure the effects of charge transfer. Here we provide a new method of quantification that overcomes this challenge, at least for 2D materials, and is robust to experimental parameters such as noise, sample tilt.

On central focusing for contrast optimization in direct electron ptychography of thick samples

Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples.

What sports activity levels can be achieved in the long-term after major lower extremity amputation for malignant tumors? - A minimum follow-up of twenty years

BACKGROUND

It is well-known that exercise through sports and physical activity has beneficial effects on health. After lower extremity amputation, low rates of participation in sports activities have been shown. So far, there is only limited scientific long-term information concerning sports activity and feasible types of sports in patients with lower extremity amputations due to malignant tumors. This study sought to provide very long-term information about the following questions: (1) What sports activity levels can be achieved after lower extremity amputation due to a malignant tumor? (2) What are feasible types of sports? (3) Is the University of California Los Angeles (UCLA) Activity Score influenced by patient's age, the age at the time of surgery and the amount of prosthesis sockets used to date?

HYPOTHESIS

Patients with lower extremity amputation due to a malignant tumor cannot regularly participate in moderate sports activities (UCLA Activity Score≥6) in the very long-term.

MATERIALS AND METHODS

In a retrospective questionnaire survey, 21 former patients (seven females, 14 males; median age: 60.5years [range: 33-74]) who underwent an amputation of the lower extremity (14 transfemoral, four knee disarticulations, three transtibial) from 1961 to 1993 due to a malignant tumor were interviewed. The median follow-up was 41.1years (range: 23-55). The patients were interviewed about types of sports, frequencies and durations of sports sessions at the time of the last follow-up, as well as retrospectively. Sports activity levels were then assessed based on the UCLA Activity Score. Demographic background, data on amputation level, histological results, prosthetic devices and revision surgeries were collected.

RESULTS

Seven patients (33%) were still regularly exercising at least moderate sports activities at the last follow-up, including one patient regularly participating in impact sports. The preoperative median UCLA Activity Score of 9 (range: 2-10) decreased to 5 (range: 2-10) at the last follow-up (p<0.001). Swimming (13 patients, seven on a regular basis), cycling (seven), downhill skiing (five) and hiking (four) were among the most common feasible types of sports. Increasing age had a negative influence on the UCLA Activity Score [95% CI (-0.034, -0.006); R_B=-0.020; SD=0.0074; p=0.007].

CONCLUSION

After a major amputation in the lower extremity due to a malignant tumor, high activity levels by practicing types of sports such as downhill skiing, are achievable. In the very long-term, a regular participation in at least moderate activities, such as swimming, is possible. Programs for physical and sports activities, based on recommendations drawn from long-term experience, are necessary and should be individually tailored to amputees and their limitations.

LEVEL OF EVIDENCE

IV.

Toward Exotic Layered Materials: 2D Cuprous Iodide

Heterostructures composed of 2D materials are already opening many new possibilities in such fields of technology as electronics and magnonics, but far more could be achieved if the number and diversity of 2D materials were increased. So far, only a few dozen 2D crystals have been extracted from materials that exhibit a layered phase in ambient conditions, omitting entirely the large number of layered materials that may exist at other temperatures and pressures. This work demonstrates how such structures can be stabilized in 2D van der Waals (vdw) stacks under room temperature via growing them directly in graphene encapsulation by using graphene oxide as the template material. Specifically, an ambient stable 2D structure of copper and iodine, a material that normally only occurs in layered form at elevated temperatures between 645 and 675 K, is produced. The results establish a simple route to the production of more exotic phases of materials that would otherwise be difficult or impossible to stabilize for experiments in ambient.

Event driven 4D STEM acquisition with a Timepix3 detector: Microsecond dwell time and faster scans for high precision and low dose applications

Four dimensional scanning transmission electron microscopy (4D STEM) records the scattering of electrons in a material in great detail. The benefits offered by 4D STEM are substantial, with the wealth of data it provides facilitating for instance high precision, high electron dose efficiency phase imaging via centre of mass or ptychography based analysis. However the requirement for a 2D image of the scattering to be recorded at each probe position has long placed a severe bottleneck on the speed at which 4D STEM can be performed. Recent advances in camera technology have greatly reduced this bottleneck, with the detection efficiency of direct electron detectors being especially well suited to the technique. However even the fastest frame driven pixelated detectors still significantly limit the scan speed which can be used in 4D STEM, making the resulting data susceptible to drift and hampering its use for low dose beam sensitive applications. Here we report the development of the use of an event driven Timepix3 direct electron camera that allows us to overcome this bottleneck and achieve 4D STEM dwell times down to 100 ns; orders of magnitude faster than what has been possible with frame based readout. We characterize the detector for different acceleration voltages and show that the method is especially well suited for low dose imaging and promises rich datasets without compromising dwell time when compared to conventional STEM imaging.

Aligned Stacking of Nanopatterned 2D Materials for High-Resolution 3D Device Fabrication

Two-dimensional materials can be combined by placing individual layers on top of each other, so that they are bound only by their van der Waals interaction. The sequence of layers can be chosen arbitrarily, enabling an essentially atomic-level control of the material and thereby a wide choice of properties along one dimension. However, simultaneous control over the structure in the in-plane directions is so far still rather limited. Here, we combine spatially controlled modifications of 2D materials, using focused electron irradiation or electron beam induced etching, with the layer-by-layer assembly of van der Waals heterostructures. The presented assembly process makes it possible to structure each layer with an arbitrary pattern prior to the assembly into the heterostructure. Moreover, it enables a stacking of the layers with accurate lateral alignment, with an accuracy of currently 10 nm, under observation in an electron microscope. Together, this enables the fabrication of almost arbitrary 3D structures with highest spatial resolution.

Enhanced intrapulse difference frequency generation in the mid-infrared by a spectrally dependent polarization state

We present a technique to optimize the intrapulse difference frequency generation efficiency for mid-infrared generation. The approach employs a multi-order wave plate that is designed to selectively rotate the polarization state of the incoming spectral components on the relevant orthogonal axes for subsequent nonlinear interaction. We demonstrate a significant increase of the mid-infrared average power generated, of a factor ≥2.5 compared with the conventional scheme, owing to an optimally distributed number of photons enrolled in the difference frequency generation process.

How Common Are Chronic Residual Limb Pain, Phantom Pain, and Back Pain More Than 20 Years After Lower Limb Amputation for Malignant Tumors?

BACKGROUND

After major lower limb amputation, persistent pain is common, with up to 85% of patients reporting recurring phantom or residual-limb pain. Although pain management is an important factor of quality of life in patients with lower limb amputations, there are few long-term data regarding the frequency of persistent pain and how it impacts prosthesis use.

QUESTIONS/PURPOSES

(1) How prevalent are different types of pain at long-term follow-up after amputation for malignant tumors? (2) What association do different pain types have with daily prosthesis use?

METHODS

Between 1961 and 1995, 124 major amputations for malignant tumors were performed at one center in Austria in patients (1) who spoke German and (2) whose surgical date resulted in the possibility of a minimum follow-up time of 20 years at the time of this survey; those patients were considered potentially eligible for this retrospective study. The indications for major amputation were to achieve local tumor control in limbs that the surgeon deemed unsalvageable without amputation. Of those 124 patients, 71% (88) had died, 9% (11) could not be reached, and 3% (4) declined to participate. Thus, 58% (21 of 36) of those living at the time of this study and who underwent lower limb amputation between 1961 and 1993 with a median (range) follow-up duration of 41 years (23 to 55) completed a standardized questionnaire, including an assessment of pain and daily prosthesis use during the year before the survey. Phantom pain, residual limb pain, and back pain were each further subclassified into pain frequency, intensity, and restrictions in activities of daily living (ADL) due to the specific pain form and rated on a 5- (pain frequency) and 10-point (pain intensity, restrictions in ADL) numerical rating scale. Before multivariate regression analysis, daily prosthesis use was correlated with pain parameters using Spearman correlation testing.

RESULTS

Seventeen of 21 patients reported phantom limb and back pain, and 15 patients reported residual limb pain in the past year. Median (range) phantom pain intensity was 7 (1 to 10) points, median residual limb pain intensity was 4 (1 to 9) points, and median back pain intensity was 5 (1 to 10) points. After controlling for relevant confounding variables such as age at amputation, age at survey, and stump length, we found that less intense residual limb pain (defined on a 10-point scale with 1 representing no pain at all and 10 representing extremely strong pain [95% CI 0.3 to 1.0]; r = 0.8; p = 0.003) was associated with greater daily prosthesis use. Higher amputation levels showed a decreased daily prosthesis use compared with patients with lower amputation levels (defined as transfemoral amputation versus knee disarticulation versus transtibial amputation [95% CI 0.3 to 5.1]; r = 0.5; p = 0.03).

CONCLUSION

Decades after surgery, many patients with lower limb amputations experience pain that restricts them in terms of ADLs and decreases their daily prosthesis use. This information supports the need for regular residual limb inspections and careful prosthesis fitting even at long-term follow-up, as effective prosthesis fitting is a modifiable cause of residual limb pain. Future studies evaluating long-term treatment effects of pain relief surgery and therapeutic alternatives to conservative pain treatments should be performed, as these approaches may help alleviate pain in patients with refractory postamputation pain.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Atom-by-atom chemical identification from scanning transmission electron microscopy images in presence of noise and residual aberrations

The simple dependence of the intensity in annular dark field scanning transmission electron microscopy images on the atomic number provides (to some extent) chemical information about the sample, and even allows an elemental identification in the case of light-element single-layer samples. However, the intensity of individual atoms and atomic columns is affected by residual aberrations and the confidence of an identification is limited by the available signal to noise. Here, we show that matching a simulation to an experimental image by iterative optimization provides a reliable analysis of atomic intensities even in presence of residual non-round aberrations. We compare our new method with other established approaches demonstrating its high reliability for images recorded at limited dose and with different aberrations. This is of particular relevance for analyzing moderately beam-sensitive materials, such as most 2D materials, where the limited sample stability often makes it difficult to obtain spectroscopic information at atomic resolution.

Cross-cultural adaption, translation and validation of the Toronto extremity salvage score (TESS) for patients in German-speaking countries

Objective

The preferred treatment for malignant bone and soft tissue tumors is limb salvage surgery; the Toronto extremity salvage score (TESS) is commonly used to measure physical functioning of the affected extremity. The aims of this study were to translate and culturally adapt the German version of the TESS, as well as to explore its convergent reliability, validity and re-test reliability.

Study design

Patients (n = 50) 32 lower extremity (LE) and 18 upper extremity (UE) were asked to fill out the German TESS two times (t1: clinical visit, t2: regular email) and the SF-36 once.

Methods

The TESS questionnaires were translated from English into German, back translated into English, and culturally adapted. The reliability was assessed with Cronbach’s alpha (α). The validity was measured with the SF-36 physical component score and TESS using the Spearman rank correlation coefficient (r). Furthermore, the test-retest reliability was calculated with the intraclass correlation coefficient (ICC).

Results

Internal consistency for both questionnaires was excellent (LE t1: α = 0.924, t2: α = 0.952; UE t1: α = 0.957, t2: α = 0.898). A statistically significant correlation was found between the SF-36 physical component scale and the German TESS (LE r = 0.741, UE r = 0.713). The ICC between baseline (t1) and re-test (t2) was 0.952 and 0.871 for the lower and upper extremities, respectively.

Conclusion

Initial evidence demonstrated that the German TESS is a valid and reliable instrument for use with patients after surgical treatment of malignant bone or soft tissue sarcoma.

Supplementary Information

The online version of this article (10.1007/s00508-021-01865-4) contains supplementary material, which is available to authorized users.

Tailoring Electronic and Magnetic Properties of Graphene by Phosphorus Doping

The electronic and magnetic properties of graphene can be modulated by doping it with other elements, especially those with a different number of valence electrons. In this article, we first provide a three-dimensional reconstruction of the atomic structure of a phosphorus substitution in graphene using aberration-corrected scanning transmission electron microscopy. Turning then to theoretical calculations based on the density functional theory (DFT), we show that doping phosphorus in various bonding configurations can induce magnetism in graphene. Our simulations reveal that the electronic and magnetic properties of P-doped (Gr-P) and/or phosphono-functionalized graphene (Gr-PO₃H₂) can be controlled by both the phosphorus concentration and configurations, ultimately leading to ferromagnetic (FM) and/or antiferromagnetic (AFM) features with the transition temperature up to room temperature. We also calculate core-level binding energies of variously bonded P to facilitate X-ray photoelectron spectroscopy-based identification of its chemical form present in P-doped graphene-based structures. These results may enable the design of graphene-based organic magnets with tailored properties for future magnetic or spintronic applications.

An empirical assessment of appearance descriptors applied to MRI for automated diagnosis of TLE and MCI

OBJECTIVE

Differential diagnosis of mild cognitive impairment MCI and temporal lobe epilepsy TLE is a debated issue, specifically because these conditions may coincide in the elderly population. We evaluate automated differential diagnosis based on characteristics derived from structural brain MRI of different brain regions.

METHODS

In 22 healthy controls, 19 patients with MCI, and 17 patients with TLE we used scale invariant feature transform (SIFT), local binary patterns (LBP), and wavelet-based features and investigate their predictive performance for MCI and TLE.

RESULTS

The classification based on SIFT features resulted in an accuracy of 81% of MCI vs. TLE and reasonable generalizability. Local binary patterns yielded satisfactory diagnostic performance with up to 94.74% sensitivity and 88.24% specificity in the right Thalamus for the distinction of MCI vs. TLE, but with limited generalizable. Wavelet features yielded similar results as LPB with 94.74% sensitivity and 82.35% specificity but generalize better.

SIGNIFICANCE

Features beyond volume analysis are a valid approach when applied to specific regions of the brain. Most significant information could be extracted from the thalamus, frontal gyri, and temporal regions, among others. These results suggest that analysis of changes of the central nervous system should not be limited to the most typical regions of interest such as the hippocampus and parahippocampal areas. Region-independent approaches can add considerable information for diagnosis. We emphasize the need to characterize generalizability in future studies, as our results demonstrate that not doing so can lead to overestimation of classification results.

LIMITATIONS

The data used within this study allows for separation of MCI and TLE subjects using a simple age threshold. While we present a strong indication that the presented method is age-invariant and therefore agnostic to this situation, new data would be needed for a rigorous empirical assessment of this findings.

Discontinuous Galerkin isogeometric analysis for segmentations generating overlapping regions

In the Isogeometric Analysis (IGA) framework, the computational domain has very often a multipatch representation. The multipatch domain can be obtained by a volume segmentation of a boundary represented domain, e.g. provided by a Computer Aided Design model. Typically, small gaps and overlapping regions can appear at the patch interfaces of such multipatch representations. In the current work, we consider multipatch representations having only small overlapping regions between the patches. We develop a Discontinuous Galerkin (DG)-IGA method that can be immediately applied to these representations. Our method appropriately connects the fluxes of the one face of the overlapping region with the flux of the opposite face. We provide a theoretical justification of our approach by splitting the whole error into two components: the first is related to the incorrect representation of the patches (consistency error) and the second to the approximation properties of the IGA space. We show bounds for both components of the error. We verify the theoretical error estimates in a series of numerical examples.

High-resolution remote thermometry and thermography using luminescent low-dimensional tin-halide perovskites

Although metal-halide perovskites have recently revolutionized research in optoelectronics through a unique combination of performance and synthetic simplicity, their low-dimensional counterparts can further expand the field with hitherto unknown and practically useful optical functionalities. In this context, we present the strong temperature dependence of the photoluminescence lifetime of low-dimensional, perovskite-like tin-halides and apply this property to thermal imaging. The photoluminescence lifetimes are governed by the heat-assisted de-trapping of self-trapped excitons, and their values can be varied over several orders of magnitude by adjusting the temperature (up to 20 ns °C^-1). Typically, this sensitive range spans up to 100 °C, and it is both compound-specific and shown to be compositionally and structurally tunable from -100 to 110 °C going from [C(NH₂)₃]₂SnBr₄ to Cs₄SnBr₆ and (C₄N₂H₁₄I)₄SnI₆. Finally, through the implementation of cost-effective hardware for fluorescence lifetime imaging, based on time-of-flight technology, these thermoluminophores have been used to record thermographic videos with high spatial and thermal resolution.

Long-term implant of intramuscular sensors and nerve transfers for wireless control of robotic arms in above-elbow amputees

Targeted muscle reinnervation (TMR) amplifies the electrical activity of nerves at the stump of amputees by redirecting them in remnant muscles above the amputation. The electrical activity of the reinnervated muscles can be used to extract natural control signals. Nonetheless, current control systems, mainly based on noninvasive muscle recordings, fail to provide accurate and reliable control over time. This is one of the major reasons for prosthetic abandonment. This prospective interventional study includes three unilateral above-elbow amputees and reports the long-term (2.5 years) implant of wireless myoelectric sensors in the reinnervation sites after TMR and their use for control of robotic arms in daily life. It therefore demonstrates the clinical viability of chronically implanted myoelectric interfaces that amplify nerve activity through TMR. The patients showed substantial functional improvements using the implanted system compared with control based on surface electrodes. The combination of TMR and chronically implanted sensors may drastically improve robotic limb replacement in above-elbow amputees.

Engineering single-atom dynamics with electron irradiation

Atomic engineering is envisioned to involve selectively inducing the desired dynamics of single atoms and combining these steps for larger-scale assemblies. Here, we focus on the first part by surveying the single-step dynamics of graphene dopants, primarily phosphorus, caused by electron irradiation both in experiment and simulation, and develop a theory for describing the probabilities of competing configurational outcomes depending on the postcollision momentum vector of the primary knock-on atom. The predicted branching ratio of configurational transformations agrees well with our atomically resolved experiments. This suggests a way for biasing the dynamics toward desired outcomes, paving the road for designing and further upscaling atomic engineering using electron irradiation.

Watt-scale 50-MHz source of single-cycle waveform-stable pulses in the molecular fingerprint region

We report a coherent mid-infrared (MIR) source with a combination of broad spectral coverage (6-18 μm), high repetition rate (50 MHz), and high average power (0.5 W). The waveform-stable pulses emerge via intrapulse difference-frequency generation (IPDFG) in a GaSe crystal, driven by a 30-W-average-power train of 32-fs pulses spectrally centered at 2 μm, delivered by a fiber-laser system. Electro-optic sampling (EOS) of the waveform-stable MIR waveforms reveals their single-cycle nature, confirming the excellent phase matching both of IPDFG and of EOS with 2-μm pulses in GaSe.

Use of failure-to-rescue to identify international variation in postoperative care in low-, middle- and high-income countries: a 7-day cohort study of elective surgery

Background

The incidence and impact of postoperative complications are poorly described. Failure-to-rescue, the rate of death following complications, is an important quality measure for perioperative care but has not been investigated across multiple health care systems.

Methods

We analysed data collected during the International Surgical Outcomes Study, an international 7-day cohort study of adults undergoing elective inpatient surgery. Hospitals were ranked by quintiles according to surgical procedural volume (Q1 lowest to Q5 highest). For each quintile we assessed in-hospital complications rates, mortality, and failure-to-rescue. We repeated this analysis ranking hospitals by risk-adjusted complication rates (Q1 lowest to Q5 highest).

Results

A total of 44 814 patients from 474 hospitals in 27 low-, middle-, and high-income countries were available for analysis. Of these, 7508 (17%) developed one or more postoperative complication, with 207 deaths in hospital (0.5%), giving an overall failure-to-rescue rate of 2.8%. When hospitals were ranked in quintiles by procedural volume, we identified a three-fold variation in mortality (Q1: 0.6% vs Q5: 0.2%) and a two-fold variation in failure-to-rescue (Q1: 3.6% vs Q5: 1.7%). Ranking hospitals in quintiles by risk-adjusted complication rate further confirmed the presence of important variations in failure-to-rescue, indicating differences between hospitals in the risk of death among patients after they develop complications.

Conclusions

Comparison of failure-to-rescue rates across health care systems suggests the presence of preventable postoperative deaths. Using such metrics, developing nations could benefit from a data-driven approach to quality improvement, which has proved effective in high-income countries.

Atomic-Scale Deformations at the Interface of a Mixed-Dimensional van der Waals Heterostructure

Molecular self-assembly due to chemical interactions is the basis of bottom-up nanofabrication, whereas weaker intermolecular forces dominate on the scale of macromolecules. Recent advances in synthesis and characterization have brought increasing attention to two- and mixed-dimensional heterostructures, and it has been recognized that van der Waals (vdW) forces within the structure may have a significant impact on their morphology. Here, we suspend single-walled carbon nanotubes (SWCNTs) on graphene to create a model system for the study of a 1D-2D molecular interface through atomic-resolution scanning transmission electron microscopy observations. When brought into contact, the radial deformation of SWCNTs and the emergence of long-range linear grooves in graphene revealed by the three-dimensional reconstruction of the heterostructure are observed. These topographic features are strain-correlated but show no sensitivity to carbon nanotube helicity, electronic structure, or stacking order. Finally, despite the random deposition of the nanotubes, we show that the competition between strain and vdW forces results in aligned carbon-carbon interfaces spanning hundreds of nanometers.

Factors Affecting Volume Changes of the Somatosensory Cortex in Patients with Spinal Cord Injury: To Be Considered for Future Neuroprosthetic Design

Spinal cord injury (SCI) leads to severe chronic disability, but also to secondary adaptive changes upstream to the injury in the brain which are most likely induced due to the lack of afferent information. These neuroplastic changes are a potential target for innovative therapies such as neuroprostheses, e.g., by stimulation in order to evoke sensation or in order to suppress phantom limb pain. Diverging results on gray matter atrophy have been reported in patients with SCI. Detectability of atrophy seems to depend on the selection of the regions of interest, while whole-brain approaches are not sensitive enough. In this study, we discussed previous research approaches and analyzed differential atrophic changes in incomplete SCI using manual segmentation of the somatosensory cortex. Patients with incomplete SCI (ASIA C-D), with cervical (N = 5) and thoracic (N = 6) injury were included. Time since injury was ≤12 months in 7 patients, and 144, 152, 216, and 312 months in the other patients. Age at the injury was ≤26 years in 4 patients and ≥50 years in 7 patients. A sample of 12 healthy controls was included in the study. In contrast to all previous studies that used voxel-based morphometry, we performed manual segmentation of the somatosensory cortex in the postcentral gyrus from structural magnetic resonance images and normalized the calculated volumes against the sum of volumes of an automated whole-head segmentation. Volumes were smaller in patients than in controls (p = 0.011), and as a tendency, female patients had smaller volumes than male patients (p = 0.017, uncorrected). No effects of duration (subacute vs. chronic), level of lesion (cervical vs. thoracic), region (left vs. right S1), and age at onset (≤26 vs. ≥50 years) was found. Our results demonstrate volume loss of S1 in incomplete SCI and encourage further research with larger sample sizes on volumetric changes in the acute and chronic stage of SCI, in order to document the moderating effect of type and location of injury on neuroplastic changes. A better understanding of neuroplastic changes in the sensorimotor cortex after SCI and its interaction with sex is needed in order to develop efficient rehabilitative interventions and neuroprosthetic technologies.

Automated Image Acquisition for Low-Dose STEM at Atomic Resolution

Beam damage is a major limitation in electron microscopy that becomes increasingly severe at higher resolution. One possible route to circumvent radiation damage, which forms the basis for single-particle electron microscopy and related techniques, is to distribute the dose over many identical copies of an object. For the acquisition of low-dose data, ideally no dose should be applied to the region of interest before the acquisition of data. We present an automated approach that can collect large amounts of data efficiently by acquiring images in a user-defined area-of-interest with atomic resolution. We demonstrate that the stage mechanics of the Nion UltraSTEM, combined with an intelligent algorithm to move the sample, allow the automated acquisition of atomically resolved images from micron-sized areas of a graphene substrate. Moving the sample stage automatically in a regular pattern over the area-of-interest enables the collection of data from pristine sample regions without exposing them to the electron beam before recording an image. Therefore, it is possible to obtain data with minimal dose (no prior exposure during focusing), which is only limited by the minimum signal needed for data processing. This enables us to minimize beam-induced damage in the sample and to acquire large data sets within a reasonable amount of time.

A novel mechanotronic orthosis enables symmetrical gait kinematics in a patient with a femoral nerve palsy - a case study

The usage of stance- and swing-phase control orthoses (SSCOs) is a good option in patients with neuromuscular insufficiency of the quadriceps muscle in a broad range of musculo-skeletal disorders. The subjective sensation of improved mobility in daily life and walking comfort could be objectively confirmed by the ability to walk without crutches and by harmonization of the gait patterns in hip and knee. They could also be a considered mobility device after limb salvage surgery, which may even have an impact on preoperative decision making. IMPLICATIONS FOR REHABILITATION Symmetric gate in spite of femoral nerve palsy. Early gate improvements even after hours. High patient?s motivation to use the device.

Enhancement cavities for few-cycle pulses

We address the challenge of increasing the bandwidth of high-finesse femtosecond enhancement cavities and demonstrate a broad spectrum spanning 1800  cm^-1 (195 nm) at -10  dB around a central wavelength of 1050 nm in an EC with an average finesse exceeding 300. This will benefit a host of spectroscopic applications, including transient absorption spectroscopy, direct frequency comb spectroscopy, and Raman spectroscopy. The pulse circulating in the EC is composed of only 5.4 optical cycles, at a kilowatt-level average power. Together with a suitable gating technique, this paves the way to the efficient generation of multi-megahertz-repetition-rate isolated extreme ultraviolet attosecond pulses via intracavity high-order harmonic generation.

Fluid challenges in intensive care: the FENICE study: A global inception cohort study

Background

Fluid challenges (FCs) are one of the most commonly used therapies in critically ill patients and represent the cornerstone of hemodynamic management in intensive care units. There are clear benefits and harms from fluid therapy. Limited data on the indication, type, amount and rate of an FC in critically ill patients exist in the literature. The primary aim was to evaluate how physicians conduct FCs in terms of type, volume, and rate of given fluid; the secondary aim was to evaluate variables used to trigger an FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC.

Methods

This was an observational study conducted in ICUs around the world. Each participating unit entered a maximum of 20 patients with one FC.

Results

2213 patients were enrolled and analyzed in the study. The median [interquartile range] amount of fluid given during an FC was 500 ml (500–1000). The median time was 24 min (40–60 min), and the median rate of FC was 1000 [500–1333] ml/h. The main indication for FC was hypotension in 1211 (59 %, CI 57–61 %). In 43 % (CI 41–45 %) of the cases no hemodynamic variable was used. Static markers of preload were used in 785 of 2213 cases (36 %, CI 34–37 %). Dynamic indices of preload responsiveness were used in 483 of 2213 cases (22 %, CI 20–24 %). No safety variable for the FC was used in 72 % (CI 70–74 %) of the cases. There was no statistically significant difference in the proportion of patients who received further fluids after the FC between those with a positive, with an uncertain or with a negatively judged response.

Conclusions

The current practice and evaluation of FC in critically ill patients are highly variable. Prediction of fluid responsiveness is not used routinely, safety limits are rarely used, and information from previous failed FCs is not always taken into account.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-015-3850-x) contains supplementary material, which is available to authorized users.

Consensus on circulatory shock and hemodynamic monitoring. Task force of the European Society of Intensive Care Medicine

OBJECTIVE

Circulatory shock is a life-threatening syndrome resulting in multiorgan failure and a high mortality rate. The aim of this consensus is to provide support to the bedside clinician regarding the diagnosis, management and monitoring of shock.

METHODS

The European Society of Intensive Care Medicine invited 12 experts to form a Task Force to update a previous consensus (Antonelli et al.: Intensive Care Med 33:575-590, 2007). The same five questions addressed in the earlier consensus were used as the outline for the literature search and review, with the aim of the Task Force to produce statements based on the available literature and evidence. These questions were: (1) What are the epidemiologic and pathophysiologic features of shock in the intensive care unit? (2) Should we monitor preload and fluid responsiveness in shock? (3) How and when should we monitor stroke volume or cardiac output in shock? (4) What markers of the regional and microcirculation can be monitored, and how can cellular function be assessed in shock? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock? Four types of statements were used: definition, recommendation, best practice and statement of fact.

RESULTS

Forty-four statements were made. The main new statements include: (1) statements on individualizing blood pressure targets; (2) statements on the assessment and prediction of fluid responsiveness; (3) statements on the use of echocardiography and hemodynamic monitoring.

CONCLUSIONS

This consensus provides 44 statements that can be used at the bedside to diagnose, treat and monitor patients with shock.

Mitral valve surgery in severe congenital factor VII deficiency

The estimated incidence of congenital factor VII deficiency is 1:500 000. Severe FVII deficiency is associated with spontaneous bleeding such as intraarticular or intracranial haemorrhage. The risk of perioperative bleeding is high during cardiac surgery as a result of the exposure to extracorporeal circulation, systemic anticoagulation, loss of coagulation factors, and postoperative platelet malfunction. Effective treatment of pre-existing coagulopathy is crucial, as increased morbidity and mortality are associated with allogenic blood transfusions. We report a 67-year-old Caucasian male patient with severe congenital FVII deficiency, undergoing successful and uneventful elective mitral valve repair surgery, radiofrequency epicardial atrial fibrillation ablation, and exclusion of the left atrial appendage. He presented with severe symptomatic mitral valve regurgitation, moderate pulmonary artery hypertension, and paroxysmal atrial fibrillation; his left ventricular ejection fraction was 67%. Three years before surgery, during a routine assessment of a grade I renal failure, a spontaneous International Normalised Ratio of 4.1 was observed. He had no history of previous spontaneous bleeding. The diagnosis of a severe FVII deficiency, with an FVII activity below 2% (normal references values in City Hospital Triemli Zurich: 55-170%) was made.

[Lichen sclerosus in the genitourinary region]

Lichen sclerosus (LS) is a chronic inflammatory disorder of the skin and mucosa, presenting to genitourinary physicians, pediatricians, and dermatologists. It affects both sexes with a lower incidence in men than in women. Autoimmune factors, infections, and genetic disposition are implicated in its pathogenesis. The classic clinical picture is of atrophic white plaques in the anogenital region. Pruritus, soreness, difficulty retracting the foreskin, and obstructive urinary symptoms are frequent complaints. Early histological confirmation by biopsy is recommended. The disorder is usually highly responsive to ultrapotent topical steroids. This may help arrest or delay the progressive nature of this disorder. Surgical treatment may be needed in cases of disease progression despite medical therapy. Circumcision is a successful treatment, if LS is limited to the glans and foreskin. In cases of meatal stenosis meatoplasty and in cases of urethral involvement one- or two-stage oral graft urethroplasty is necessary.

Stable muscle atrophy in long-term paraplegics with complete upper motor neuron lesion from 3- to 20-year SCI

STUDY DESIGN

Unrandomized trial.

OBJECTIVES

To investigate the structural and functional relationships and the progression of muscle atrophy up to 20 years of spastic paraplegia.

SETTING

Clinical follow-up in Vienna, Austria; muscle biopsies analyzed by light microscopy in Padova and by electron microscopy (EM) in Chieti, Italy.

METHODS

Force was measured as knee extension torque; trophism by computer tomography scan; tissue composition and fiber morphology by histopathology and EM.

RESULTS

In the long-term group of patients (17.0+/-2.6 years), force and size of thigh muscles were only slightly different from those of mid-term subjects (2.2+/-0.5 years). Histology and ultrastructure confirm that the difference in average size of muscle fibers between long-term and mid-term paralyzed leg muscles is actually very small. In addition, muscle fibers maintain the striated appearance characteristic of normal skeletal fibers even after 14-20 years of paralysis. Ultrastructural alterations of the activating and metabolic machineries, and the presence of fibers with lower motor neuron denervation features, may explain the low-force output and the reduced endurance of paretic muscles.

CONCLUSION

The stable muscle atrophy that characterizes long-lasting spastic paraplegia suggests that there are no upper-time limits to begin a training program based on functional electrical stimulation.

Adrenergic Receptor Genotype but Not Perioperative Bisoprolol Therapy May Determine Cardiovascular Outcome in At-risk Patients Undergoing Surgery with Spinal Block

Background:

Neuraxial blockade is used as primary anesthetic technique in one third of surgical procedures. The authors tested whether bisoprolol would protect patients at risk for cardiovascular complications undergoing surgery with spinal block.

Methods:

The authors performed a double-blinded, placebo-controlled, multicenter trial to compare the effect of bisoprolol with that of placebo on 1-yr composite outcome including cardiovascular mortality, nonfatal myocardial infarction, unstable angina, congestive heart failure, and cerebrovascular insult. Bisoprolol was given orally before and after surgery for a maximum of 10 days. Adrenergic receptor polymorphisms and safety outcome measures of bisoprolol therapy were also determined.

Results:

A total of 224 patients were enrolled. Spinal block could not be established in 5 patients. One hundred ten patients were assigned to the bisoprolol group, and 109 patients were assigned to the placebo group. The mean duration of treatment was 4.9 days in the bisoprolol group and 5.1 days in the placebo group. Bisoprolol therapy reduced mean heart rate by 10 beats/min. The primary outcome was identical between treatment groups and occurred in 25 patients (22.7%) in the bisoprolol group and 24 patients (22.0%) in the placebo group during the 1-yr follow-up (hazard ratio, 0.97; 95% confidence interval, 0.55–1.69; P = 0.90). However, carriers of at least one Gly allele of the β1-adrenergic receptor polymorphism Arg389Gly showed a higher number of adverse events than Arg homozygous (32.4% vs. 18.7%; hazard ratio, 1.87; 95% confidence interval, 1.04–3.35; P = 0.04).

Conclusions:

Perioperative bisoprolol therapy did not affect cardiovascular outcome in these elderly at-risk patients undergoing surgery with spinal block.

Gene Regulatory Control of Myocardial Energy Metabolism Predicts Postoperative Cardiac Function in Patients Undergoing Off-pump Coronary Artery Bypass Graft Surgery

Background

Anesthetic gases modulate gene expression and provide organ protection. This study aimed at identifying myocardial transcriptional phenotypes to predict cardiovascular biomarkers and function in patients undergoing off-pump coronary artery bypass graft surgery.

Methods

In a prospective randomized trial, patients undergoing elective off-pump coronary artery bypass graft surgery were allocated to receive either the anesthetic gas sevoflurane (n = 10) or the intravenous anesthetic propofol (n = 10). Blood samples were collected perioperatively to determine cardiac troponin T, N-terminal pro-brain natriuretic peptide, and pregnancy-associated plasma protein A. Cardiac function was measured with transesophageal echocardiography and pulmonary artery thermodilution. Atrial biopsies were collected at the beginning and end of bypass surgery to determine gene expression profiles.

Results

N-terminal pro-brain natriuretic peptide and pregnancy-associated plasma protein A blood levels were decreased with sevoflurane treatment. Echocardiography showed preserved postoperative cardiac function in sevoflurane patients, which paralleled higher cardiac index measurements. N-terminal pro-brain natriuretic peptide release was predicted by sevoflurane-induced transcriptional reduction in fatty acid oxidation, whereas changes in cardiac index were predicted by preoperative gene activity of the peroxisome proliferator-activated receptor gamma coactivator-1alpha pathway. Sevoflurane-mediated attenuation of transcripts involved in DNA-damage signaling and activation of the granulocyte colony-stimulating factor survival pathway predicted improved postoperative cardiac index and diastolic heart function, respectively.

Conclusions

Anesthetic-induced and constitutive gene regulatory control of myocardial substrate metabolism predicts postoperative cardiac function in patients undergoing off-pump coronary artery bypass graft surgery. The authors' analysis further points to novel cardiac survival pathways as potential therapeutic targets in perioperative cardioprotection.

Off-Pump Coronary Artery Bypass Grafting: The Zurich Experience

Coronary artery bypass grafting (CABG) is the surgical procedure of choice for treatment of multi-vessel coronary artery disease. The rising risk profile of the patients requiring isolated CABG and the economic pressure have prompted us to devise new operative strategies to treat these patients. Elimination of the cardiopulmonary bypass is one possible answer to the dilemma of maintaining the quality of care and reducing the exploding costs of our health system. Therefore, we developed the off-pump coronary artery bypass grafting (OPCAB) for patients requiring isolated CABG. In our experience the key to successful OPCAB relies on the order of revascularization of the myocardial walls (anterior, inferior, lateral), use of intracoronary shunt, no-touch technique for the proximal aortic anastomosis with heart string â (Guidant, IN, USA), close collaboration with the anesthesiologists, early and aggressive administration of anti-platelet therapy, endoscopic vein harvest by perfusionists, and improved body temperature control. Following these concepts, we have been able to offer the OPCAB procedure to over 90% of our patients and to reduce perioperative morbidity and global costs.

Defaulting from anti-tuberculosis treatment in a teaching hospital in Rio de Janeiro, Brazil

SETTING

Few studies have investigated factors associated with defaulting from anti-tuberculosis (TB) therapy in hospital settings.

OBJECTIVE

To identify the factors associated with defaulting from treatment among TB in-patients in Rio de Janeiro city, Brazil.

DESIGN

Case-control study.

METHODS

All study participants initiated anti-tuberculosis treatment in a teaching hospital. A defaulting case was defined as a person who did not return for anti-tuberculosis medications after 60 days. Cases and controls were interviewed by a trained health care worker using a standardized form.

RESULTS

From 1 January to 31 December 1997, 228 TB cases were registered. After a review of the medical records, 39 were excluded. Household visits were performed in 189 patients; 46 subjects were identified as cases and 117 as controls. Defaulting from anti-tuberculosis treatment was observed in 66 cases (28.9%) before and in 46 (20.2%) after a home visit. After multivariate analysis, the strongest predictors of defaulting from treatment were: 1) returning card not provided (OR 0.099; 95%CI 0.008-1.2; P = 0.07), 2) not feeling comfortable with a doctor (OR 0.16; 95%CI 0.33-0.015; P = 0.001), and 3) blood pressure not measured (OR 0.072; 95%CI 0.036-0.79; P = 0.024).

CONCLUSIONS

In this hospital, the factors associated with defaulting from anti-tuberculosis treatment highlight the necessity for a structured TB Control Program. It is expected that the implementation of such a program, pursuing specific approaches, should enhance completion of anti-tuberculosis treatment and cure.