Evolution of point defects in pulsed-laser-melted Ge1-xSnxprobed by positron annihilation lifetime spectroscopy

Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy grown Ge1-xSnxfilms treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening - variable energy positron annihilation spectroscopy and variable energy positron annihilation lifetime spectroscopy are used to investigate the defect nanostructure in the Ge1-xSnxfilms exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, the positron annihilation spectroscopy analysis provides information about dislocations and Ge vacancies decorated by Sn atoms. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters.

Band-gap and strain engineering in GeSn alloys using post-growth pulsed laser melting

The pseudomorphic growth of Ge_1-xSn_xon Ge causes in-plane compressive strain, which degrades the superior properties of the Ge_1-xSn_xalloys. Therefore, efficient strain engineering is required. In this article, we present strain and band-gap engineering in Ge_1-xSn_xalloys grown on Ge a virtual substrate using post-growth nanosecond pulsed laser melting (PLM). Micro-Raman and x-ray diffraction (XRD) show that the initial in-plane compressive strain is removed. Moreover, for PLM energy densities higher than 0.5 J cm^-2, the Ge_0.89Sn_0.11layer becomes tensile strained. Simultaneously, as revealed by Rutherford Backscattering spectrometry, cross-sectional transmission electron microscopy investigations and XRD the crystalline quality and Sn-distribution in PLM-treated Ge_0.89Sn_0.11layers are only slightly affected. Additionally, the change of the band structure after PLM is confirmed by low-temperature photoreflectance measurements. The presented results prove that post-growth ns-range PLM is an effective way for band-gap and strain engineering in highly-mismatched alloys.

Field-resolved THz-pump laser-probe measurements with CEP-unstable THz light sources

Radiation sources with a stable carrier-envelope phase (CEP) are highly demanded tools for field-resolved studies of light-matter interaction, providing access both to the amplitude and phase information of dynamical processes. At the same time, many coherent light sources, including those with outstanding power and spectral characteristics lack CEP stability, and so far could not be used for this type of research. In this work, we present a method enabling linear and non-linear phase-resolved terahertz (THz) -pump laser-probe experiments with CEP-unstable THz sources. THz CEP information for each pulse is extracted using a specially designed electro-optical detection scheme. The method correlates the extracted CEP value for each pulse with the THz-induced response in the parallel pump-probe experiment to obtain an absolute phase-resolved response after proper sorting and averaging. As a proof-of-concept, we demonstrate experimentally field-resolved THz time-domain spectroscopy with sub-cycle temporal resolution using the pulsed radiation of a CEP-unstable infrared free-electron laser (IR-FEL) operating at 13 MHz repetition rate. In spite of the long history of IR-FELs and their unique operational characteristics, no successful realization of CEP-stable operation has been demonstrated yet. Being CEP-unstable, IR-FEL radiation has so far only been used in non-coherent measurements without phase resolution. The technique demonstrated here is robust, operates easily at high-repetition rates and for short THz pulses, and enables common sequential field-resolved time-domain experiments. The implementation of such a technique at IR-FEL user end-stations will facilitate a new class of linear and non-linear experiments for studying coherent light-driven phenomena with increased signal-to-noise ratio.

MYT1L-associated neurodevelopmental disorder: description of 40 new cases and literature review of clinical and molecular aspects

Pathogenic variants of the myelin transcription factor-1 like (MYT1L) gene include heterozygous missense, truncating variants and 2p25.3 microdeletions and cause a syndromic neurodevelopmental disorder (OMIM#616,521). Despite enrichment in de novo mutations in several developmental disorders and autism studies, the data on clinical characteristics and genotype-phenotype correlations are scarce, with only 22 patients with single nucleotide pathogenic variants reported. We aimed to further characterize this disorder at both the clinical and molecular levels by gathering a large series of patients with MYT1L-associated neurodevelopmental disorder. We collected genetic information on 40 unreported patients with likely pathogenic/pathogenic MYT1L variants and performed a comprehensive review of published data (total = 62 patients). We confirm that the main phenotypic features of the MYT1L-related disorder are developmental delay with language delay (95%), intellectual disability (ID, 70%), overweight or obesity (58%), behavioral disorders (98%) and epilepsy (23%). We highlight novel clinical characteristics, such as learning disabilities without ID (30%) and feeding difficulties during infancy (18%). We further describe the varied dysmorphic features (67%) and present the changes in weight over time of 27 patients. We show that patients harboring highly clustered missense variants in the 2-3-ZNF domains are not clinically distinguishable from patients with truncating variants. We provide an updated overview of clinical and genetic data of the MYT1L-associated neurodevelopmental disorder, hence improving diagnosis and clinical management of these patients.

Vascular malformations of the female and male genitalia: type and distribution patterns revealed by magnetic resonance imaging

BACKGROUND

Vascular malformations of the genitalia often go undetected in clinical examination. These vascular malformations can cause a variety of clinical symptoms such as swelling, pain and bleeding.

AIM

To characterize the distribution patterns of genital vascular malformations using magnetic resonance imaging (MRI) and to correlate these patterns with clinical findings in order to guide diagnostic decisions.

METHODS

A retrospective analysis of MRIs of the pelvis and legs in 370 patients with vascular malformation was performed to determine the involvement of the internal and external genitalia.

RESULTS

In 71 patients (19%), genital involvement could be identified by MRI. Of these, 11.3% (8 of 71) presented with internal involvement, 36.6% (26 of 71) with external involvement and 52.1% (37 of 71) with both internal and external involvement. Over half (57.1%) of the 49 patients with visible external genital signs detected during a clinical examination had additional internal genital involvement.

CONCLUSIONS

Genital involvement is a common finding in patients with vascular malformation of the legs and/or pelvis. Based on our data, we recommend MRI of the legs and pelvic region in patients with externally visible signs of a vascular malformation of the external genitalia in order to exclude additional internal involvement.

Time Refraction of Spin Waves

We present an experimental study of time refraction of spin waves (SWs) propagating in microscopic waveguides under the influence of time-varying magnetic fields. Using space- and time-resolved Brillouin light scattering microscopy, we demonstrate that the broken translational symmetry along the time coordinate results in a loss of energy conservation for SWs and thus allows for a broadband and controllable shift of the SW frequency. With an integrated design of SW waveguide and microscopic current line for the generation of strong, nanosecond-long, magnetic field pulses, a conversion efficiency up to 39% of the carrier SW frequency is achieved, significantly larger compared to photonic systems. Given the strength of the magnetic field pulses and its strong impact on the SW dispersion relation, the effect of time refraction can be quantified on a length scale comparable to the SW wavelength. Furthermore, we utilize time refraction to excite SW bursts with pulse durations in the nanosecond range and a frequency shift depending on the pulse polarity.

[Prehospital application of tourniquets for life-threatening extremity hemorrhage : Systematic review of literature]

INTRODUCTION

The effectiveness of a tourniquet in the case of life-threatening hemorrhages of the extremities is well recognized and led to the recommendations on "Tourniquet" of the German Society of Anaesthesiology and Intensive Care (DGAI) in 2016. The aim of this systematic review was to re-evaluate the current medical literature in relation to the published DGAI recommendations.

MATERIAL AND METHODS

Based on the analysis of all studies published from January 2015 until January 2018 in the PubMed databases, the publicized recommendations for action on "Tourniquet" of the DGAI were critically re-evaluated. For this purpose, 17 questions on 6 subjects were formulated in advance. The systematic review followed the PRISMA recommendations and is registered in PROSPERO (International prospective register of systematic reviews, Reg.-ID: CRD42018091528).

RESULTS

Of the 284 studies identified with the keywords tourniquet and trauma in the period from January 2015 to January 2018 in PubMed, 50 original papers discussing the prehospital application of tourniquet for life-threatening hemorrhage of the extremities were included. The overall level of evidence is low. No article addressed any of the formulated questions with a prospective randomized interventional study. Scientific deductions could be found only in an indirect way in a descriptive manner.

CONCLUSION

The 50 original articles included in this qualitative, systematic review revealed that the recommendations "Tourniquet" of the DGAI published in 2016 are mostly still up to date despite an inhomogeneous study situation. A deviation occurred in the conversion of a tourniquet but due to the short prehospital treatment time in the civilian setting this is of little importance; however, in the future a strict distinction should be made between tourniquets which were placed for tactical reasons and those placed as a medical necessity.

In-vitro study of species-specific coagulation differences in animals and humans using rotational thromboelastometry (ROTEM)

Animal tests are conducted in all fields of trauma research, but transferability of these data to humans is limited. For example, it is still unclear which animal species is most similar to humans in terms of physiology of blood coagulation. To improve transferability and raise awareness of the existing differences, we compared human coagulation to coagulation of different animals. Rotational thromboelastometry was used to analyse the blood of pigs, sheep, rabbits and dogs. Animal data were compared with human coagulation based on the number of significant differences of the test parameters and on a descriptive comparison of the extent of relative deviation of the single values. All animal species showed significant differences in coagulation properties when compared with humans. Coagulation parameters of dogs and sheep were on average most similar to humans. However, there is no animal which is most similar to humans concerning all aspects of coagulation. Differences in coagulation between humans and animals are significant. This must be taken into account when transferring animal test data to humans.

Formation of n- and p-type regions in individual Si/SiO2 core/shell nanowires by ion beam doping

A method for cross-sectional doping of individual Si/SiO₂ core/shell nanowires (NWs) is presented. P and B atoms are laterally implanted at different depths in the Si core. The healing of the implantation-related damage together with the electrical activation of the dopants takes place via solid phase epitaxy driven by millisecond-range flash lamp annealing. Electrical measurements through a bevel formed along the NW enabled us to demonstrate the concurrent formation of n- and p-type regions in individual Si/SiO₂ core/shell NWs. These results might pave the way for ion beam doping of nanostructured semiconductors produced by using either top-down or bottom-up approaches.

Comparative study of equivalent circuit models for photoconductive antennas

Comparison of equivalent circuit models (ECM) for photoconductive antennas (PCA) represents a challenge due to the multiphysics phenomena involved during PCA operation and the absence of a standardized validation methodology. In this work, currently reported ECMs are compared using a unique set of simulation parameters and validation indicators (THz waveform, optical power saturation, and ECM voltages consistency). The ECM simulations are contrasted with measured THz pulses of an H-shaped 20μm gap PCA at different optical powers (20mW to 220mW). In addition, an alternative two-element ECM that accounts for both space-charge and radiation screening effects is presented and validated using the proposed methodology. The model shows an accurately reproduced THz pulse using a reduced number of circuital elements, which represents an advantage for PCA modeling.

Structured analysis, evaluation and report of the emergency response to a terrorist attack in Wuerzburg, Germany using a new template of standardised quality indicators

Background

Until now there has been a reported lack of systematic reports and scientific evaluations of rescue missions during terror attacks. This however is urgently required in order to improve the performance of emergency medical services and to be able to compare different missions with each other. Aim of the presented work was to report the systematic evaluation and the lessons learned from the response to a terror attack that happened in Wuerzburg, Germany in 2016.

Methods

A team of 14 experts developed a template of quality indicators and operational characteristics, which allow for the description, assessment and comparison of civil emergency rescue missions during mass killing incidents. The entire systematic evaluation process consisted of three main steps. The first step was the systematic data collection according to the quality indicators and operational characteristics. Second was the systematic stratification and assessment of the data. The last step was the prioritisation of the identified weaknesses and the definition of the lessons learned.

Results

Five important “lessons learned” have been defined. First of all, a comprehensive concept for rescue missions during terror attacks is essential. Furthermore, the establishment of a defined high priority communication infrastructure between the different dispatch centres (“red phone”) is vital. The goal is to secure the continuity of information between a few well-defined individuals. Thirdly, the organization of the incident scene needs to be commonly decided and communicated between police, medical services and fire services during the mission. A successful mission tactic requires continuous flux of reports to the on-site command post. Therefore, a predefined and common communication infrastructure for all operational forces is a crucial point. Finally, all strategies need to be extensively trained before the real life scenario hits.

Conclusion

According to a systematic evaluation, we defined the lessons learned from a terror attack in 2016. Further systematic reports and academic work surrounding life threatening rescue missions and mass killing incidents are needed in order to ultimately improve such mission outcomes. In the future, a close international collaboration might help to find the best database to report and evaluate major incidents but also mass killing events.

[Future of emergency medicine in Germany 2.0]

In 2003 an article on the future of prehospital emergency medicine in Germany was published in the journal Der Anaesthesist. Emergency medicine in Germany, which at that time was almost exclusively defined as prehospital emergency rescue, has evolved and now in-hospital domains have increasingly moved into the focus. At that time, the primary goal was to connect prehospital management with a smooth transition to hospital admission and further care in the hospital and to further optimize the rescue chain from the actual emergency through to causative treatment. Now after 15 years, the authors have critically assessed the development postulated in 2003 and reevaluated it. Which aspects could be developed further and become firmly established, what is still open and which questions in preclinical and clinical emergency treatment of the population will occupy us in the coming 15 years? With a critical eye to the past, the present contribution aims to capture the essential and new topics and open questions and provide a fresh perspective for the future of emergency medicine. Regulation at the state level or even lower levels of government often stand in contrast to more sweeping and economically effective approaches at the federal level. Prehospital emergency medicine in Germany is on the whole well-positioned with respect to facilities and personnel; however, as far as the economic situation and the utilization of available systems are concerned, there is still substantial room for improvement.

Monovacancy paramagnetism in neutron-irradiated graphite probed by 13C NMR

We report on the magnetic properties of monovacancy defects in neutron-irradiated graphite, probed by ¹³C nuclear magnetic resonance spectroscopy. The bulk paramagnetism of the defect moments is revealed by the temperature dependence of the NMR frequency shift and spectral linewidth, both of which follow a Curie behavior, in agreement with measurements of the macroscopic magnetization. Compared to pristine graphite, the fluctuating hyperfine fields generated by the defect moments lead to an enhancement of the ¹³C nuclear spin-lattice relaxation rate [Formula: see text] by about two orders of magnitude. With an applied magnetic field of 7.1 T, the temperature dependence of [Formula: see text] below about 10 K can well be described by a thermally activated form, [Formula: see text], yielding a singular Zeeman energy of ([Formula: see text]) meV, in excellent agreement with the sole presence of polarized, non-interacting defect moments.

A multilayered electrospun graft as vascular access for hemodialysis

Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access-an autogenous arteriovenous fistula-is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.

Doubly Dressed Bosons: Exciton Polaritons in a Strong Terahertz Field

We demonstrate the existence of a novel quasiparticle, an exciton in a semiconductor doubly dressed with two photons of different wavelengths: a near infrared cavity photon and terahertz (THz) photon, with the THz coupling strength approaching the ultrastrong coupling regime. This quasiparticle is composed of three different bosons, being a mixture of a matter-light quasiparticle. Our observations are confirmed by a detailed theoretical analysis, treating quantum mechanically all three bosonic fields. The doubly dressed quasiparticles retain the bosonic nature of their constituents, but their internal quantum structure strongly depends on the intensity of the applied terahertz field.

[Out-of-hospital airway management in trauma patients : Experiences with the C-MAC® video laryngoscope]

BACKGROUND

Securing the airway is the top priority in trauma resuscitation. The most important factor for successful endotracheal intubation (ETI) is good visualization of the vocal cords. The aim of this study was to summarize the practical experiences with the C-MAC® video laryngoscope as initial device in out-of-hospital airway management of trauma patients.

METHODS

The C-MAC® video laryngoscope uses standard Macintosh shaped laryngoscope blades. At the Helicopter Emergency Medical Service (HEMS) Christoph 22 it is used as the initial device for every out-of-hospital ETI. All prehospital data on ETI involving trauma patients were documented for a period of 17 months.

RESULTS

A total of 116 out-of-hospital ETIs were enrolled in this study (overall success rate 100 %). In 88.8 % the first attempt was successful, whereas in 10.3 % a second and in 0.9 % a third ETI attempt was necessary. No patient required alternative airway devices or surgical airway interventions. The results of a subgroup with an immobilized cervical spine (n = 17) did not show any increased difficulties.

CONCLUSION

The use of the C-MAC® video laryngoscope by experienced anesthesiologists in an out-of-hospital setting seems to be a safe method even in patients with an immobilized cervical spine. Adverse laryngoscopy results (C/L III and IV) were reduced compared to other studies.

[Civilian blast injuries: an underestimated problem? : Results of a retrospective analysis of the TraumaRegister DGU®]

BACKGROUND

Blast injuries are a rare cause of potentially life-threatening injuries in Germany. During the past 30 years such injuries were seldom the cause of mass casualties, therefore, knowledge and skills in dealing with this type of injury are not very extensive.

MATERIAL AND METHODS

A retrospective identification of all patients in the TraumaRegister DGU® of the German Trauma Society (TR-DGU) who sustained blast injuries between January 1993 and November 2012 was carried out. The study involved a descriptive characterization of the collective as well as three additional collectives. The arithmetic mean, standard deviation and 95 % confidence interval of the arithmetic mean for different demographic parameters and figures for prehospital and in-hospital settings were calculated. A computation of prognostic scores, such as the Revised Injury Severity Classification (RISC) and the updated version RISC II (TR-DGU-Project-ID 2012-035) was performed.

RESULTS

A total of 137 patients with blast injuries could be identified in the dataset of the TR-DGU. Of the patients 90 % were male and 43 % were transported by the helicopter emergency service (HEMS) to the various trauma centres. The severely injured collective with a mean injury severity scale (ISS) of 18.0 (ISS ≥ 16 = 52 %) had stable vital signs. In none of the cases was it necessary to perform on-site emergency surgery but a very high proportion of patients (59 %) had to be surgically treated before admittance to the intensive care unit (ICU). Of the patients 27 % had severe soft tissue injuries with an Abbreviated Injury Scale (AIS) ≥ 3 and 90 % of these injuries were burns. The 24 h in-hospital fatality was very low (3 %) but the stay in the ICU tended to be longer than for other types of injury (mean 5.5 ventilation days and 10.7 days in the intensive care unit). Organ failure occurred in 36 % of the cases, multiorgan failure in 29 % and septic events in 14 %. Of the patients 16 % were transferred to another hospital during the first 48 h. The RISC and the updated RISC II tended to underestimate the severity of injuries and mortality (10.2 % vs. 6.8 % and 10.7 % vs. 7.5 %, respectively) and the trauma associated severe hemorrhage (TASH) score underestimated the probability for transfusion of more than 10 units of packed red blood cells (5.0 % vs. 12.5 %).

CONCLUSION

This article generates several hypotheses, which should be confirmed with additional investigations. Until then it has to be concluded that patients who suffer from accidental blast injuries in the civilian setting (excluding military operations and terrorist attacks) show a combination of classical severe trauma with blunt and penetrating injuries and additionally a high proportion of severe burns (combined thermomechanical injury). They stay longer in the ICU than other trauma patients and suffer more complications, such as sepsis and multiorgan failure. Established scores, such as RISC, RISC II and TASH tend to underestimate the severity of the underlying trauma.

[Quality indicators for rescue operations in terrorist attacks or other threats : A pilot study after the Würzburg terrorist attack of July 2016]

BACKGROUND

Terrorist attacks have become reality in Germany. The aim of this work was, after the Würzburg terrorist attack, to define quality indicators and application characteristics for rescue missions in life-threatening situations. The results can be used to record data from future missions using this template in order to make them comparable with each other.

METHODS

After approval of the local ethic committee, the first step was to designate a group of experts in order to define the template in a consensus process. The next step was to perform the consensus process by defining the template. An independent expert for emergency medicine and disaster management reviewed and approved the results afterwards.

RESULTS

The expert group defined 13 categories and 158 parameters that will further serve the systematic evaluation of the rescue mission of the Würzburg terror attack. Preliminary results of this evaluation process are given in this paper; the full evaluation has not yet been completed.

DISCUSSION

In this study we first describe quality indicators and parameters suitable for the German rescue system in order to evaluate rescue operations for violence caused mass casualties. There is similar international documentation, but it does not specifically focus on life-threatening operations and are not adapted to the German context.

CONCLUSION

There is an important need to systematically evaluate rescue missions after mass killing incidents. In this study we report a template of parameters and quality indicators in order to systematically evaluate mass violence events. The presented template is the result of an expert consensus process and may serve as a basis for further development and research.

[Care for severely injured persons : Update of the 2016 S3 guideline for the treatment of polytrauma and the severely injured]

In 2011 the first interdisciplinary S3 guideline for the management of patients with serious injuries/trauma was published. After intensive revision and in consensus with 20 different medical societies, the updated version of the guideline was published online in September 2016. It is divided into three sections: prehospital care, emergency room management and the first operative phase. Many recommendations and explanations were updated, mostly in the prehospital care and emergency room management sections. These two sections are of special interest for anesthesiologists in field emergency physician roles or as team members or team leaders in the emergency room. The present work summarizes the changes to the current guideline and gives a brief overview of this very important work.

[Consideration of guidelines, recommendations and quality indicators for treatment of stroke in the dataset "Emergency Department" of DIVI]

BACKGROUND

The dataset "Emergency Department" of the German Interdisciplinary Association of Critical Care and Emergency Medicine (DIVI) has been developed during several expert meetings. Its goal is an all-encompassing documentation of the early clinical treatment of patients in emergency departments. Using the example of the index disease acute ischemic stroke (stroke), the aim was to analyze how far this approach has been fulfilled.

MATERIAL AND METHODS

In this study German, European and US American guidelines were used to analyze the extent of coverage of the datasets on current emergency department guidelines and recommendations from professional societies. In addition, it was examined whether the dataset includes recommended quality indicators (QI) for quality management (QM) and in a third step it was examined to what extent national provisions for billing are included. In each case a differentiation was made whether the respective rationale was primary, i.e. directly apparent or whether it was merely secondarily depicted by expertise. In the evaluation an additional differentiation was made between the level of recommendations and further quality relevant criteria.

RESULTS

The modular design of the emergency department dataset comprising 676 data fields is briefly described. A total of 401 individual fields, divided into basic documentation, monitoring and specific neurological documentation of the treatment of stroke patients were considered. For 247 data fields a rationale was found. Partially overlapping, 78.9 % of 214 medical recommendations in 3 guidelines and 85.8 % of the 106 identified quality indicators were primarily covered. Of the 67 requirements for billing of performance of services, 55.5 % are primarily part of the emergency department dataset. Through appropriate expertise and documentation by a board certified neurologist, the results can be improved to almost 100 %.

CONCLUSION

The index disease stroke illustrates that the emergency department dataset of the DIVI covers medical guidelines, especially 100 % of the German guidelines with a grade of recommendation. All necessary information to document the specialized stroke treatment procedure in the German diagnosis-related groups (DRG) system is also covered. The dataset is also suitable as a documentation tool of quality management, for example, to participate in the registry of the German Stroke Society (ADSR). Best results are obtained if the dataset is applied by a physician specialized in the treatment of patients with stroke (e.g. board certified neurologist). Finally the results show that changes in medical guidelines and recommendations for quality management as well as billing-relevant content should be implemented in the development of datasets for documentation to avoid duplicate documentation.

Slow Noncollinear Coulomb Scattering in the Vicinity of the Dirac Point in Graphene

The Coulomb scattering dynamics in graphene in energetic proximity to the Dirac point is investigated by polarization resolved pump-probe spectroscopy and microscopic theory. Collinear Coulomb scattering rapidly thermalizes the carrier distribution in k directions pointing radially away from the Dirac point. Our study reveals, however, that, in almost intrinsic graphene, full thermalization in all directions relying on noncollinear scattering is much slower. For low photon energies, carrier-optical-phonon processes are strongly suppressed and Coulomb mediated noncollinear scattering is remarkably slow, namely on a ps time scale. This effect is very promising for infrared and THz devices based on hot carrier effects.

Effectiveness of a rehabilitation programme in chronic bronchitis and emphysema

Thirty-nine patients with stable chronic bronchitis and emphysema were randomly allocated into two groups. Eight withdrew before the study and six during the study. One group received six weeks active outpatient rehabilitation, the other (control) group six weeks attendance without rehabilitation. Before entry, patients were examined to assess stability and measure arterial blood gases. On both entry and completion the following were recorded: smoking history; carboxyhaemoglobin; FEVI; six minute walking distance (6MD); the General Health Questionnaire (GHQ) and visual analogue scale (VAS) of breathlessness.

The treatment group showed a significant (p > 0.01) reduction in GHQ score after rehabilitation, suggesting a decrease in psychiatric symptoms. In the control group, the GHQ score reduction was not statistically significant. The control group, but not the treatment group, showed a significant (p > 0.05) increase in 6MD. No significant difference was found in FEV1, VAS score, or the number of patients smoking after rehabilitation. Our rehabilitation programme appeared to benefit patients' psychological wellbeing, but this may be due to attendance at the groups rather than the rehabilitation programme per se. Underlying disease severity or perception of disability did not change.

Initial assessment and treatment of refugees in the Mediterranean Sea (a secondary data analysis concerning the initial assessment and treatment of 2656 refugees rescued from distress at sea in support of the EUNAVFOR MED relief mission of the EU)

Background

As a part of the European Union Naval Force – Mediterranean Operation Sophia (EUNAVFOR Med), the Federal Republic of Germany is contributing to avoid further loss of lives at sea by supplying two naval vessels. In the study presented here we analyse the medical requirements of such rescue missions, as well as the potential benefits of various additional monitoring devices in identifying sick/injured refugees within the primary onboard medical assessment process.

Methods

Retrospective analysis of the data collected between May – September 2015 from a German Naval Force frigate. Initial data collection focused on the primary medical assessment and treatment process of refugees rescued from distress at sea. Descriptive statistics, uni- and multivariate analysis were performed. The study has received a positive vote from the Ethics Commission of the University of Ulm, Germany (request no. 284/15) and has been registered in the German Register of Clinical Studies (no. DRKS00009535).

Results

A total of 2656 refugees had been rescued. 16.9 % of them were classified as “medical treatment required” within the initial onboard medical assessment process. In addition to the clinical assessment by an emergency physician, pulse rate (PR), core body temperature (CBT) and oxygen saturation (SpO₂) were evaluated. Sick/injured refugees displayed a statistically significant higher PR (114/min vs. 107/min; p < .001) and CBT (37.1 °C vs. 36.7 °C; p < .001). There was no statistically significant difference in SpO₂-values. The same results were found for the subgroup of patients classified as “treatment at emergency hospital required”. However, a much larger difference of the mean PR and CBT (35/min resp. 1.8 °C) was found when examining the subgroups of the corresponding refugee boats. A cut-off value of clinical importance could not be found. Predominant diagnoses have been dermatological diseases (55.4), followed by internal diseases (27.7) and trauma (12.1 %). None of the refugees classified as “healthy” within the primary medical assessment process changed to “medical treatment required” during further observation.

Conclusions

The initial medical assessment by an emergency physician has proved successful. PR, CBT and SpO₂ didn’t have any clinical impact to improve the identification of sick/injured refugees within the primary onboard assessment process.

Electronic supplementary material

The online version of this article (doi:10.1186/s13049-016-0270-z) contains supplementary material, which is available to authorized users.

[Patients with Acute, Non-Traumatic Abdominal Pain in German Emergency Departments: A Prospective Monocentric Observation Study]

Background: Up to 11 % of patients in an Emergency Department (ED) present with non-traumatic acute abdominal pain. Based on this presenting symptom, this study aimed to analyse how residents (surgery, internal medicine, anaesthesiology and other fields) working in an ED during their second and third year of education treat these patients. Material and Methods: We performed a prospective, monocentric observation study in an ED in accordance with the STROBE recommendations, following the recommendations from the Ethics Committee of the University of Ulm (application no. 335/12) and the Declaration of Helsinki. The hospital's data protection officer approved the study. During a 12-month period (Dec. 2012 to Dec. 2013), a random sample of patients with non-traumatic abdominal pain was obtained in the ED of a major German acute care hospital by an independent observer, who was not part of the ED team. In addition to demographic data, the study focused on analysing processes and patient care (including medical history taking and physical examinations). In addition, subgroups were defined (clinical background of the treating physician, severity pursuant to the Manchester Triage Score [MTS]). Results: 143 patients met the inclusion criteria. The clinical background of the physician had no influence on the reviewed processes such as medical history taking, initial examinations, the request of consultative examinations or diagnostic procedures. Patients triaged as "urgent" were treated significantly earlier than patients triaged as "non-urgent" (time to first physician contact 26 ± 24 vs. 46 ± 34 min, p < 0.001). However, the overall time spent in the ED was equal (210 ± 79 vs. 220 ± 114 min, p = 0.555). Yet the initially estimated urgency was correlated with the need for hospitalisation (share: 57 %). Conclusion: The overall compliance with standards of care was high. The clinical background (surgery, internal medicine, anaesthesiology, other fields) of the physician in charge of initial treatment had no influence on the reviewed processes.

Biodegradable hyperbranched polyether-lipids with in-chain pH-sensitive linkages

Hyperbranched polyether-based lipids with cleavable acetal units were obtained via copolymerization of the epoxide inimer 1-(glycidyloxy)ethyl ethylene glycol ether (GEGE) and glycidol, using anionic ring-opening polymerization.

Single-pulse picking at kHz repetition rates using a Ge plasma switch at the free-electron laser FELBE

We demonstrate a system for picking of mid-infrared and terahertz (THz) radiation pulses from the free-electron laser (FEL) FELBE operating at a repetition rate of 13 MHz. Single pulses are reflected by a dense electron-hole plasma in a Ge slab that is photoexcited by amplified near-infrared (NIR) laser systems operating at repetition rates of 1 kHz and 100 kHz, respectively. The peak intensity of picked pulses is up to 400 times larger than the peak intensity of residual pulses. The required NIR fluence for picking pulses at wavelengths in the range from 5 μm to 30 μm is discussed. In addition, we show that the reflectivity of the plasma decays on a time scale from 100 ps to 1 ns dependent on the wavelengths of the FEL and the NIR laser. The plasma switch enables experiments with the FEL that require high peak power but lower average power. Furthermore, the system is well suited to investigate processes with decay times in the μs to ms regime, i.e., much longer than the 77 ns long pulse repetition period of FELBE.

Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy

Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping of chalcogen into the silicon matrix. However, this method encounters the problem of surface segregation. In this paper, we propose a solid phase processing by flash-lamp annealing in the millisecond range, which is in between the conventional rapid thermal annealing and pulsed laser annealing. Flash lamp annealed selenium-implanted silicon shows a substitutional fraction of ~ 70% with an implanted concentration up to 2.3%. The resistivity is lower and the carrier mobility is higher than those of nanosecond pulsed laser annealed samples. Our results show that flash-lamp annealing is superior to laser annealing in preventing surface segregation and in allowing scalability.

[National data set "emergency department": development, structure and approval by the Deutsche Interdisziplinäre Vereinigung für Intensivmedizin und Notfallmedizin]

BACKGROUND

The Deutsche Interdisziplinäre Vereinigung für Intensivmedizin und Notfallmedizin (DIVI) is divided into sections one of which is the "Sektion Notaufnahmeprotokoll" (emergency department protocol section) founded in 2007. The main task was to create a national data set for the documentation of patients in emergency departments (ED).

MATERIAL AND METHODS

In order to create such a data set a careful look was taken at the current state of documentation in many different hospitals throughout Germany. In addition, existing registries and international requirements were also taken into consideration. The content of the dataset "ED documentation" was developed in interdisciplinary and interprofessional expert rounds.

RESULTS

The dataset "ED documentation" forms the first basis for documentation in German EDs. The modular data set contains 676 fields and covers all relevant information of the whole clinical process in the ED. Legal issues as well as several aspects for internal and external quality management are also included. For this reason the data of several German quality registries (e.g. TraumaRegister DGU® of the German Society of Trauma Surgery) are part of the data set. Furthermore, the data set forms the basis for several financial and billing aspects. A set of six forms was created in accordance with the developed modular data set. In 2010 the data set was approved by the executive committee of the DIVI. Several German medical associations (e.g. German Association for Emergency Medicine/Deutsche Gesellschaft Interdisziplinäre Notfall- und Akutmedizin, DGINA) recommend its use. Currently 80 hospitals are using the data set.

CONCLUSION

Beside the ability to exchange information the presented data set is the basis for internal and external quality assessment in the ED even if most of the available scoring and benchmarking tools are not validated for the German medical system. Implementing an ED register in Germany which is planned in the future, could close this gap.

Microscopic description of intraband absorption in graphene: the occurrence of transient negative differential transmission

We present a microscopic explanation of the controversially discussed transient negative differential transmission observed in degenerate optical pump-probe measurements in graphene. Our approach is based on the density matrix formalism allowing a time- and momentum-resolved study of carrier-light, carrier-carrier, and carrier-phonon interaction on microscopic footing. We show that phonon-assisted optical intraband transitions give rise to transient absorption in the optically excited hot carrier system counteracting pure absorption bleaching of interband transitions. While interband transition bleaching is relevant in the first hundreds of fs after the excitation, intraband absorption sets in at later times. In particular, in the low excitation regime, these intraband absorption processes prevail over the absorption bleaching resulting in a zero crossing of the differential transmission. Our findings are in good qualitative agreement with recent experimental pump-probe studies.