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1.
J Psychiatr Res ; 173: 124-130, 2024 May.
Article in English | MEDLINE | ID: mdl-38522166

ABSTRACT

INTRODUCTION: We investigated the antidepressant effects of a novel oral prolonged-release formulation of racemic ketamine (KET01) in patients suffering from treatment-resistant depression (TRD) as add-on therapy. MATERIAL AND METHODS: Patients were randomized to an additional 160 mg/day or 240 mg/day KET01 or placebo for 14 days. The primary endpoint was change in Montgomery-Åsberg Depression Rating Scale (MADRS) scores from baseline to day 15. For treatment group comparisons, we used ANOVA with pairwise least squares mean difference tests in a mixed model repeated measures analysis. RESULTS: Twenty-seven patients completed the double-blind protocol before trial premature termination due to poor recruitment during the COVID-19 pandemic. Mean (SD) MADRS scores on day 15 were 23 (10.32) in placebo, 25 (8.28) with 160 mg/day and 17 (10.32) with 240 mg/day KET01. MADRS change was numerically larger but statistically non-significant in the 240 mg/day KET01 group vs placebo on day 7 (-5.67; p = 00.106) and day 15 was (difference: 4.99; p = 00.15). In exploratory analysis, baseline leukocyte count correlated with response to KET01 (p = 00.01). Distribution of adverse event rates were comparable between the treatment arms. Safety analysis did not identify increased risk of suicidality, dissociation, hear rate, systolic and diastolic blood pressure associated with trial treatment. DISCUSSION: Our results suggest that adjunctive oral administration of prolonged-release ketamine at a dose of 240 mg/day shows a positive, although statistically non-significant, trend towards antidepressant efficacy, however, the benefit could not be confirmed due to premature trial termination. Given its ease of use and low side effects, further trials are warranted to investigate this route of ketamine administration as a promising potential treatment of TRD.


Subject(s)
COVID-19 , Depressive Disorder, Treatment-Resistant , Ketamine , Humans , Ketamine/adverse effects , Depression , Pandemics , Antidepressive Agents/adverse effects , Double-Blind Method , Depressive Disorder, Treatment-Resistant/drug therapy , Treatment Outcome
2.
Ann Bot ; 129(5): 607-618, 2022 04 13.
Article in English | MEDLINE | ID: mdl-35136917

ABSTRACT

BACKGROUND AND AIMS: Drought limits maize production in many regions of the world, and this is likely to intensify in future. Elevated atmospheric CO2 (eCO2) can mitigate this by reducing stomatal conductance and water loss without reducing yield. The magnitude of this effect depends on the interaction of eCO2 and drought severity, but scarce data collected under severe drought conditions limit predictions of future maize production. METHODS: We compared the severe drought × eCO2 responses of six maize genotypes from semi-arid and sub-humid growing regions. KEY RESULTS: Genotypic differences were apparent in growth, gas exchange, water relations, grain quality, and biomass at maturity, but the response to eCO2 was consistent. Plants under drought and eCO2 had similar biomass and yield to irrigated plants at ambient CO2. Reduced stomatal conductance and water loss preserved soil moisture equivalent to 35 mm of rainfall and allowed sustained photosynthesis at higher rates for a longer period after watering stopped. Under irrigation, eCO2 improved maize growth but not grain yield. CONCLUSIONS: The results suggest that eCO2 may extend the future land area available to rainfed maize cultivation, but cannot circumvent the absence of seasonal rainfall that restricts maize growth. Elevated CO2 will reduce water requirements of irrigated maize when atmospheric conditions drive high evapotranspiration.


Subject(s)
Droughts , Zea mays , Carbon Dioxide/analysis , Photosynthesis/physiology , Soil , Water/physiology , Zea mays/genetics
3.
Nat Commun ; 12(1): 1239, 2021 Feb 23.
Article in English | MEDLINE | ID: mdl-33623010

ABSTRACT

One of the main challenges in ultrafast material science is to trigger phase transitions with short pulses of light. Here we show how strain waves, launched by electronic and structural precursor phenomena, determine a coherent macroscopic transformation pathway for the semiconducting-to-metal transition in bistable Ti3O5 nanocrystals. Employing femtosecond powder X-ray diffraction, we measure the lattice deformation in the phase transition as a function of time. We monitor the early intra-cell distortion around the light absorbing metal dimer and the long range deformations governed by acoustic waves propagating from the laser-exposed Ti3O5 surface. We developed a simplified elastic model demonstrating that picosecond switching in nanocrystals happens concomitantly with the propagating acoustic wavefront, several decades faster than thermal processes governed by heat diffusion.

4.
Arch Orthop Trauma Surg ; 141(4): 593-602, 2021 Apr.
Article in English | MEDLINE | ID: mdl-32519074

ABSTRACT

BACKGROUND: Navigational techniques in orthopaedic trauma surgery have developed over the last years leaving the question of really improving quality of treatment. Especially in marginal surgical indications, their benefit has to be evident. The aim of this study was to compare reduction and screw position following 3D-navigated and conventional percutaneous screw fixation of acetabular fractures. The study hypothesis postulated that better fracture reduction and better screw position are obtained with 3D navigation. MATERIALS AND METHODS: Preoperative and postoperative CT scans of 37 acetabular fractures treated by percutaneous screw fixation (24 3D-navigated, 13 conventional) were evaluated. Differences in pre- and postoperative fracture gaps and steps were compared in all reconstructions as well as the screw position relative to the joint and the fracture. RESULTS: The differences in fracture gaps and fracture steps with and without 3D navigation were not significantly different. Distance of the screw from the joint line, angle difference between screw and ideal angle relative to the fracture line, length of the possible corridor used and position of the screw thread did not show any significant differences. CONCLUSION: Comparison of 3D-navigated and conventional percutaneous surgery of acetabular fractures on the basis of pre- and postoperative CTs revealed no significant differences in terms of fracture reduction and screw position.


Subject(s)
Acetabulum , Bone Screws , Fracture Fixation/methods , Fractures, Bone , Surgery, Computer-Assisted/methods , Acetabulum/diagnostic imaging , Acetabulum/injuries , Acetabulum/surgery , Fluoroscopy , Fractures, Bone/diagnostic imaging , Fractures, Bone/surgery , Humans , Imaging, Three-Dimensional
5.
Sci Rep ; 10(1): 4530, 2020 03 11.
Article in English | MEDLINE | ID: mdl-32161337

ABSTRACT

Anatomic reconstruction of articular fractures is one of the critical factors in later achieving good functional outcome. Intraoperative 3D imaging has been shown to offer better evaluation and therefore can significantly improve the results. The purpose of this study was to assess the difference between intraoperative three-dimensional fluoroscopy (3D) and intraoperative computed tomography (iCT) imaging regarding fracture reduction, implant placement and articular impressions in a distal humeral fracture model. AO type 13-B2 fracture pattern were created in upper extremity cadaver specimens. Articular step-offs, intra-articular screw placement and intraarticular impressions of different degrees of severity were created. All specimens had imaging performed. For each articular pattern 3D fluoroscopy in standard (3Ds) and high quality (3Dh) were performed (Arcadis Orbic, Siemens, Germany) as well as an intraoperative CT scan (iCT, Airo, Brainlab, Germany). Three observers evaluated all imaging studies regarding subjective and objective parameters. iCT is more precise than 3D fluoroscopic imaging for detection of articular impressions. Articular step-offs and intraarticular screw placement are similar for iCT and 3D. Subjective imaging quality is the highest for iCT and lowest for 3Ds. Intraoperative CT may be particularly useful in assessing articular impressions and providing a good subjective image quality for the surgeon.


Subject(s)
Fractures, Bone/diagnostic imaging , Imaging, Three-Dimensional/methods , Tomography, X-Ray Computed/methods , Tomography, X-Ray Computed/standards , Cadaver , Humans
6.
Chirurg ; 90(10): 782-790, 2019 Oct.
Article in German | MEDLINE | ID: mdl-31463657

ABSTRACT

Studies have shown that the numbers of injuries of the cervical spine increase in elderly patients. An early clinical examination and adequate diagnostics are necessary to initiate the appropriate treatment. A computed tomography (CT) scan is recommended to exclude injuries of the cervical spine. Dynamic fluoroscopy and magnetic resonance imaging (MRI) can additionally be helpful to detect instabilities. The treatment of the injury depends on the extent of the fracture and includes conservative treatment options with soft or rigid ortheses for cervical spine immobilization, retention with a halo fixator or open/closed reduction and fixation. In the selection of treatment it should be taken into consideration that the use of rigid immobilization or a halo fixator is associated with a significant reduction of the quality of life. In the region of the upper cervical spine only unstable fractures of the atlas and of the axis should be operatively treated. In the region of the subaxial cervical spine fractures are prone to be unstable due to the lack of flexibility of the cervical spine in elderly patients. Therefore, fractures of types B and C according to AO Spine, for which operative treatment is recommended, are regularely seen. In addition, a pre-existing stenosis of the spinal cord may lead to neurological symptoms which negatively influence the clinical outcome.


Subject(s)
Cervical Vertebrae , Quality of Life , Spinal Fractures , Spinal Injuries/surgery , Aged , Fluoroscopy , Humans , Magnetic Resonance Imaging , Spinal Fractures/surgery , Tomography, X-Ray Computed , Treatment Outcome
7.
Epidemiol Infect ; 147: e219, 2019 01.
Article in English | MEDLINE | ID: mdl-31364561

ABSTRACT

In 2013, the national surveillance case definition for West Nile virus (WNV) disease was revised to remove fever as a criterion for neuroinvasive disease and require at most subjective fever for non-neuroinvasive disease. The aims of this project were to determine how often afebrile WNV disease occurs and assess differences among patients with and without fever. We included cases with laboratory evidence of WNV disease reported from four states in 2014. We compared demographics, clinical symptoms and laboratory evidence for patients with and without fever and stratified the analysis by neuroinvasive and non-neuroinvasive presentations. Among 956 included patients, 39 (4%) had no fever; this proportion was similar among patients with and without neuroinvasive disease symptoms. For neuroinvasive and non-neuroinvasive patients, there were no differences in age, sex, or laboratory evidence between febrile and afebrile patients, but hospitalisations were more common among patients with fever (P < 0.01). The only significant difference in symptoms was for ataxia, which was more common in neuroinvasive patients without fever (P = 0.04). Only 5% of non-neuroinvasive patients did not meet the WNV case definition due to lack of fever. The evidence presented here supports the changes made to the national case definition in 2013.


Subject(s)
Asymptomatic Diseases/epidemiology , Fever/epidemiology , West Nile Fever/diagnosis , West Nile Fever/epidemiology , West Nile virus/isolation & purification , California/epidemiology , Clinical Laboratory Techniques/methods , Female , Fever/diagnosis , Humans , Incidence , Louisiana/epidemiology , Male , Massachusetts/epidemiology , Minnesota/epidemiology , Population Surveillance , Retrospective Studies , Risk Assessment , Severity of Illness Index
8.
Sci Rep ; 9(1): 2738, 2019 02 25.
Article in English | MEDLINE | ID: mdl-30804494

ABSTRACT

Diseases of the gastrointestinal tract due to changes in the bacterial flora have been described with increasing incidence in the European brown hare. Despite extensive demographic and phylogeographic research, little is known about the composition of its gut microbiota and how it might vary based on potential environmental or host factors. We analysed the intestinal and faecal microbiota of 3 hare populations by Illumina MiSeq 16S rRNA gene amplicon sequencing. The phyla and OTU abundance composition differed significantly between intestinal and faecal samples (PERMANOVA: P = 0.002 and P = 0.031, respectively), but in both sample types Firmicutes and Bacteroidetes dominated the microbial community composition (45.51% and 19.30% relative abundance). Intestinal samples contained an enrichment of Proteobacteria compared with faecal samples (15.71-fold change, P < 0.001). At OTU level, a significant enrichment with best BLAST hits to the Escherichia-Shigella group, Eubacterium limosum, Sphingomonas kyeonggiensis, Flintibacter butyricus and Blautia faecis were detected in intestinal samples (P < 0.05). In our statistical model, geographic location and possibly associated environmental factors had a greater impact on the microbiota composition than host factors. Population had a significant effect on the composition of abundant intestinal and faecal OTUs, and on the abundance of potential pathogenic bacteria of the family Enterobacteriaceae, regularly associated with intestinal dysbiosis in hares, in faecal samples. Our study is the first to describe the microbiota in brown hares and provides a foundation to generate hypothesis aiming to test the role of gut health in population fluctuations of the species.


Subject(s)
Gastrointestinal Microbiome , Hares/microbiology , Animals , Bacteria/genetics , Bacteria/isolation & purification , Bacteroidetes/genetics , Bacteroidetes/isolation & purification , Feces/microbiology , Female , Firmicutes/genetics , Firmicutes/isolation & purification , Male , RNA, Ribosomal, 16S/genetics
9.
Environ Int ; 126: 207-215, 2019 05.
Article in English | MEDLINE | ID: mdl-30802638

ABSTRACT

Food production is a major driver of environmental change, and unhealthy diets are the leading cause of global disease burden. In high-income countries (HICs), modelling studies suggest that adoption of healthy diets could improve population health and reduce environmental footprints associated with food production. We assessed whether such benefits from dietary change could occur in India, where under-nutrition and overweight and obesity are simultaneously prevalent. We calculated the potential changes in greenhouse gas (GHG) emissions, blue and green water footprints (WFs), and land use (LU), that would result from shifting current national food consumption patterns in India to healthy diets (meeting dietary guidelines) and to "affluent diets" (those consumed by the wealthiest quartile of households, which may represent future purchasing power and nutritional trajectories). Dietary data were derived from the 2011-12 nationally-representative household expenditure survey, and we assessed dietary scenarios nationally and across six Indian sub-regions, by rural or urban location, and for those consuming above or below recommended dietary energy intakes. We modelled the changes in consumption of 34 food groups necessary to meet Indian dietary guidelines, as well as an affluent diet representative of those in the highest wealth quartile. These changes were combined with food-specific data on GHG emissions, calculated using the Cool Farm Tool, and WF and LU adapted from the Water Footprint Network and Food and Agriculture Organization, respectively. Shifting to healthy guidelines nationally required a minor increase in dietary energy (3%), with larger increases in fruit (18%) and vegetable (72%) intake, though baseline proportion of dietary energy from fat and protein was adequate and did not change significantly. Meeting healthy guidelines slightly increased environmental footprints by about 3-5% across GHG emissions, blue and green WFs, and LU. However, these national averages masked substantial variation within sub-populations. For example, shifting to healthy diets among those with dietary energy intake below recommended guidelines would result in increases of 28% in GHG emissions, 18 and 34% in blue and green WFs, respectively, and 41% in LU. Decreased environmental impacts were seen among those who currently consume above recommended dietary energy (-6 to -16% across footprints). Adoption of affluent diets by the whole population would result in increases of 19-36% across the environmental indicators. Specific food groups contributing to these shifts varied by scenario. Environmental impacts also varied markedly between six major Indian sub-regions. In India, where undernutrition is prevalent, widespread adoption of healthy diets may lead to small increases in the environmental footprints of the food system relative to the status quo, although much larger increases would occur if there was widespread adoption of diets currently consumed by the wealthiest quartile of the population. To achieve lower diet-related disease burdens and reduced environmental footprints of the food system, greater efficiency of food production and reductions in food waste are likely to be required alongside promotion of healthy diets.


Subject(s)
Air Pollutants/analysis , Diet , Environment , Models, Theoretical , Humans , India
10.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1093-1094: 113-118, 2018 Sep 01.
Article in English | MEDLINE | ID: mdl-30015308

ABSTRACT

Since the importance of the high affinity between avidin and biotin, Kd = 3 × 10-16 M, gained universal recognition, numerous chemical, biological and medical avidin-biotin based applications have been developed. However, in some cases the high affinity may be a disadvantage, as this interaction is irreversible under physiological conditions. The dye, 4'-hydroxyazobenzene-2-carboxylic acid (HABA), binds avidin, at the biotin binding site, as determined by X-ray, at a much lower affinity constant, Kd = 6 × 10-6 M. We prepared a HABA affinity column (amber colored). Avidin bound to the column at a pH between 4 and 8.5, causing a change of color to red, and it could be eluted at mild conditions with buffers containing biotin, HABA, 1.5 M potassium chloride or a pH lower than 4.0 or higher than 8.5. Avidin eluted with HABA, created a red avidin-HABA complex, which was visualized. HABA free avidin was obtained by dialysis, which was followed by the loss of red coloration. The novel and easy to use HABA-affinity column was employed in our lab to prepare pure, fully glycosylated avidin from egg white. Most importantly, it may serve as an ideal tool for educational purposes, illuminating concepts of molecular recognition, reversible molecular binding, structure-based molecular design and solid phase chemical synthesis, as it is a reliable and visible reagent.


Subject(s)
Avidin , Azo Compounds/chemistry , Chromatography, Affinity/methods , Avidin/analysis , Avidin/chemistry , Avidin/isolation & purification , Avidin/metabolism , Azo Compounds/metabolism , Binding Sites , Egg White/chemistry
11.
J Synchrotron Radiat ; 24(Pt 5): 963-974, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28862618

ABSTRACT

EIGER is a single-photon-counting hybrid pixel detector developed at the Paul Scherrer Institut, Switzerland. It is designed for applications at synchrotron light sources with photon energies above 5 keV. Features of EIGER include a small pixel size (75 µm × 75 µm), a high frame rate (up to 23 kHz), a small dead-time between frames (down to 3 µs) and a dynamic range up to 32-bit. In this article, the use of EIGER as a detector for electrons in low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) is reported. It is demonstrated that, with only a minimal modification to the sensitive part of the detector, EIGER is able to detect electrons emitted or reflected by the sample and accelerated to 8-20 keV. The imaging capabilities are shown to be superior to the standard microchannel plate detector for these types of applications. This is due to the much higher signal-to-noise ratio, better homogeneity and improved dynamic range. In addition, the operation of the EIGER detector is not affected by radiation damage from electrons in the present energy range and guarantees more stable performance over time. To benchmark the detector capabilities, LEEM experiments are performed on selected surfaces and the magnetic and electronic properties of individual iron nanoparticles with sizes ranging from 8 to 22 nm are detected using the PEEM endstation at the Surface/Interface Microscopy (SIM) beamline of the Swiss Light Source.

12.
Injury ; 48(10): 2068-2073, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28774707

ABSTRACT

PURPOSE: A new software application can be used without fixed reference markers or a registration process in wire placement. The aim was to compare placement of Kirschner wires (K-wires) into the proximal femur with the software application versus the conventional method without guiding. As study hypothesis, we assumed less placement attempts, shorter procedure time and shorter fluoroscopy time using the software. The same precision inside a proximal femur bone model using the software application was premised. METHODS: The software detects a K-wire within the 2D fluoroscopic image. By evaluating its direction and tip location, it superimposes a trajectory on the image, visualizing the intended direction of the K-wire. The K-wire was positioned in 20 artificial bones with the use of software by one surgeon; 20 bones served as conventional controls. A brass thumb tack was placed into the femoral head and its tip targeted with the wire. Number of placement attempts, duration of the procedure, duration of fluoroscopy time and distance to the target in a postoperative 3D scan were recorded. RESULTS: Compared with the conventional method, use of the application showed fewer attempts for optimal wire placement (p=0.026), shorter duration of surgery (p=0.004), shorter fluoroscopy time (p=0.024) and higher precision (p=0.018). Final wire position was achieved in the first attempt in 17 out of 20 cases with the software and in 9 out of 20 cases with the conventional method. CONCLUSIONS: The study hypothesis was confirmed. The new application optimised the process of K-wire placement in the proximal femur in an artificial bone model while also improving precision. Benefits lie especially in the reduction of placement attempts and reduction of fluoroscopy time under the aspect of radiation protection. The software runs on a conventional image intensifier and can therefore be easily integrated into the daily surgical routine.


Subject(s)
Femoral Fractures/diagnostic imaging , Femur/diagnostic imaging , Fracture Fixation, Internal , Surgery, Computer-Assisted/methods , Artificial Organs , Bone Wires , Bone and Bones/diagnostic imaging , Bone and Bones/surgery , Femoral Fractures/surgery , Femur/anatomy & histology , Femur/surgery , Fluoroscopy , Fracture Fixation, Internal/methods , Humans , Models, Anatomic , Operative Time , Reproducibility of Results , Software
13.
Compr Psychiatry ; 74: 224-230, 2017 04.
Article in English | MEDLINE | ID: mdl-28236772

ABSTRACT

BACKGROUND: It is unclear whether mental illness stigma affects individuals with subthreshold syndromes outside clinical settings. We therefore investigated the role of different stigma variables, including stigma-related stress and shame reactions, for avoidant stigma coping among members of the general population with elevated symptom levels. METHODS: Based on a representative population survey, general stress resilience, stigma variables, shame about having a mental illness as well as avoidant stigma coping (secrecy and social withdrawal) were assessed by self-report among 676 participants with elevated symptom levels. Stigma variables and resilience were examined as predictors of avoidant stigma coping in a path model. RESULTS: Increased stigma stress was predicted by lower general stress resilience as well as by higher levels of perceived stigma, group identification and perceived legitimacy of discrimination. More shame was associated with higher perceived legitimacy. Lower resilience as well as more perceived stigma, group identification and perceived legitimacy predicted avoidant coping. Stigma stress partly mediated effects of resilience, perceived stigma and group identification on avoidant coping; shame partly mediated effects of perceived legitimacy on coping. Stigma stress and shame were also directly and positively related to avoidant stigma coping. Analyses were adjusted for symptoms, neuroticism and sociodemographic variables. CONCLUSIONS: Stigma may affect a larger proportion of the population than previously thought because stigma variables predicted secrecy and withdrawal among members of the general population with elevated, but overall mild symptom levels. Avoidant stigma coping likely has harmful effects, potentially exacerbating pre-existing psychological distress and undermining social networks. This highlights the need to reduce public stigma as well as to support individuals with subthreshold syndromes in their coping with stigma stress and shame reactions.


Subject(s)
Adaptation, Psychological , Avoidance Learning , Mental Disorders/psychology , Shame , Social Stigma , Stress, Psychological/psychology , Adolescent , Adult , Cross-Sectional Studies , Female , Humans , Male , Mental Disorders/diagnosis , Middle Aged , Population Surveillance/methods , Self Concept , Self Report , Social Support , Stress, Psychological/diagnosis
14.
Unfallchirurg ; 119(10): 803-10, 2016 Oct.
Article in German | MEDLINE | ID: mdl-27599821

ABSTRACT

BACKGROUND: The results and immediate consequences of intraoperative three-dimensional (3D) imaging in the treatment of AO classification type C fractures of the distal radius, the tibial head and the tibial pilon were analyzed and compared with published results on general intraoperative revision rates following intraoperative 3D-imaging. METHODS: In this retrospective study 279 patients with AO type C fractures of the distal radius (n = 84), tibial head (n = 109) and tibial pilon (n = 86) who underwent intraoperative 3D-imaging were included. The findings of the 3D-imaging and the intraoperative revision rates were analyzed and compared with previously published results of our working group. RESULTS: In 70 out of 279 patients (25 %) an intraoperative revision was carried out following 3D-imaging. The revision rates were 15 % for fractures of the distal radius, 27 % for fractures of the tibial head and 32 % for fractures of the tibial pilon. The most common reason for immediate intraoperative revision was the necessity for improved repositioning due to a remaining step in the articular surface in 51 out of 279 patients (18%). CONCLUSION: Intraoperative revision rates following 3D-imaging increased with the severity of the injury pattern. Intraoperative 3D-imaging should be routinely used in the treatment of fractures of the tibial head, tibial pilon and even in comminuted distal radius fractures due to the high intraoperative revision rates found in the present study. Alternatively, a postoperative computed tomography (CT) control should be performed.


Subject(s)
Fracture Fixation, Internal/statistics & numerical data , Imaging, Three-Dimensional/statistics & numerical data , Radius Fractures/surgery , Reoperation/statistics & numerical data , Surgery, Computer-Assisted/statistics & numerical data , Tibial Fractures/surgery , Female , Germany/epidemiology , Humans , Imaging, Three-Dimensional/methods , Male , Middle Aged , Patient Safety , Postoperative Complications/epidemiology , Postoperative Complications/prevention & control , Prevalence , Radius Fractures/diagnostic imaging , Radius Fractures/epidemiology , Reproducibility of Results , Retrospective Studies , Risk Factors , Sensitivity and Specificity , Surgery, Computer-Assisted/methods , Tibial Fractures/diagnostic imaging , Tibial Fractures/epidemiology , Treatment Outcome
15.
Phys Rev Lett ; 116(25): 254801, 2016 Jun 24.
Article in English | MEDLINE | ID: mdl-27391728

ABSTRACT

In this Letter we report the experimental demonstration of a new temporal shaping technique for x-ray free-electron lasers (FELs). This technique is based on the use of a spectrally shaped infrared (IR) laser and allows optical control of the x-ray generation process. By accurately manipulating the spectral amplitude and phase of the IR laser, we can selectively modify the electron bunch longitudinal emittance thus controlling the duration of the resulting x-ray pulse down to the femtosecond time scale. Unlike other methods currently in use, optical shaping is directly applicable to the next generation of high-average power x-ray FELs such as the Linac Coherent Light Source-II or the European X-FEL, and it enables pulse shaping of FELs at the highest repetition rates. Furthermore, this laser-shaping technique paves the way for flexible tailoring of complex multicolor FEL pulse patterns required for nonlinear multidimensional x-ray spectroscopy as well as novel multicolor diffraction imaging schemes.

16.
Unfallchirurg ; 119(1): 36-42, 2016 Jan.
Article in German | MEDLINE | ID: mdl-25648870

ABSTRACT

BACKGROUND: Digital planning of implants is in most cases conducted prior to surgery. The virtual implant planning system (VIPS) is an application developed for mobile C-arms, which assists the virtual planning of screws close to the joint line during surgery for treatment of distal radius fractures with volar plate osteosynthesis. The aim of this prospective randomized study was to acquire initial clinical experiences and to compare the VIPS method with the conventional technique. METHOD: The study included 10 patients for primary testing and 30 patients with distal radius fractures of types A3, C1 and C2, divided in 2 groups. In the VIPS group, after placement of the plate and fracture reduction, a virtual 3D model of the plate was matched with the image of the plate from the fluoroscopic acquisition. Next, the length and position of the screws close to the joint line were planned on the virtual plate. The control group was treated with the same implant in the conventional way. Data were collected regarding screw replacement, fluoroscopy and operating room (OR) times. RESULTS: The VIPS group included six A3, one C1 and eight C2 fractures, while the control group consisted of six A3 and nine C2 fractures. Three screws were replaced in the VIPS group and two in the control group (p = 0.24). The mean intraoperative fluoroscopy time of the VIPS group amounted to 2.58 ± 1.38 min, whereas it was 2.12 ± 0.73 min in the control group (p = 0.26). The mean OR time in the VIPS group was 53.3 ± 34.5 minutes and 42.3 ± 8.8 min (p = 0.23) in the control group. CONCLUSION: The VIPS enables a precise positioning of screws close to joint line in the treatment of distal radius fractures; however, for routine use, further development of the system is necessary.


Subject(s)
Bone Plates , Fracture Fixation, Internal/methods , Prosthesis Fitting/methods , Radius Fractures/surgery , Surgery, Computer-Assisted/methods , User-Computer Interface , Adult , Aged , Aged, 80 and over , Fluoroscopy/methods , Fracture Fixation, Internal/instrumentation , Humans , Imaging, Three-Dimensional/methods , Intraoperative Care/methods , Male , Middle Aged , Radius Fractures/diagnostic imaging , Treatment Outcome , Wrist Injuries/diagnostic imaging , Wrist Injuries/surgery , Young Adult
17.
Ecology ; 96(8): 2170-80, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26405742

ABSTRACT

Large-mammal herbivore populations are subject to the interaction of internal density-dependent processes and external environmental stochasticity. We disentangle these processes by linking consumer population dynamics, in a highly stochastic environment, to the availability of their key forage resource via effects on body condition and subsequent fecundity and mortality rates. Body condition and demographic rate data were obtained by monitoring 500 tagged female goats in the Richtersveld National Park, South Africa, over a three-year period. Identifying the key resource and pathway to density dependence for a population allows environmental stochasticity to be partitioned into that which has strong feedbacks to population stability, and that which does not. Our data reveal a density- dependent seasonal decline in goat body condition in response to concomitant density-dependent depletion of the dry-season forage resource. The loss in body condition reduced density-dependent pregnancy rates, litter sizes, and pre-weaning survival. Survival was lowest following the most severe dry season and for juveniles. Adult survival in the late-dry season depended on body condition in the mid-dry season. Population growth was determined by the length of the dry season and the population size in the previous year. The RNP goat population is thereby dynamically coupled primarily to its dry-season forage resource. Extreme environmental variability thus does not decouple consumer resource dynamics, in contrast to the views of nonequilibrium protagonists.


Subject(s)
Animal Husbandry , Ecosystem , Goats/physiology , Animals , Body Composition , Conservation of Natural Resources , Environment , Female , Fertility , Humans , Male , Pregnancy , South Africa , Stochastic Processes
18.
Rev Sci Instrum ; 86(7): 073702, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26233391

ABSTRACT

Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

19.
Nat Commun ; 6: 6369, 2015 Mar 06.
Article in English | MEDLINE | ID: mdl-25744344

ABSTRACT

The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitude in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.

20.
Unfallchirurg ; 118(2): 177-80, 2015 Feb.
Article in German | MEDLINE | ID: mdl-25604677

ABSTRACT

A 12-year-old boy suffered a rare occurrence of a traumatic spondylolisthesis (L5/S1) without neurological alterations after being partially buried underneath a collapsing brick wall. Additionally he sustained a third degree open fracture of the left distal fibula and epiphysiolysis of the left distal tibia. A closed reduction and percutanous dorsal instrumentation L5/S1 as well as an open reduction and osteosynthesis of the tibia and fibula were performed. After 6 months the instrumentation was completely removed and an unrestrained range of motion of the lumbar spine and the upper ankle joint was regained.


Subject(s)
Lumbar Vertebrae/injuries , Spinal Fractures/etiology , Spinal Fractures/surgery , Spinal Fusion/methods , Spondylolisthesis/complications , Spondylolisthesis/surgery , Child , Humans , Lumbar Vertebrae/surgery , Male , Spinal Fusion/instrumentation , Treatment Outcome
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