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.

Stability of Sodium Nitroprusside in 5% Dextrose Stored at 4°C in Polypropylene Syringes Protected from Light

Sodium nitroprusside is a potent vasodilator employed intraoperatively and within critical care areas. The photolabile pharmaceutical agent has been used for decades and various stability studies have been executed. Due to potential shortages and the desire to batch compound sodium nitroprusside at a concentration of 1 mg/mL in polypropylene syringes, a new stability study was performed. Chromatographic analysis was conducted on a C18 column, with elution via an aqueous phase of 0.01 M sodium phosphate monobasic, adjusted to pH 6.5 with sodium hydroxide, and methanol (97.5:2.5) at a rate of 1 mL/min, and subsequent ultraviolet detection at 210 nm. Triplicate determinations of four samples, stored under refrigeration at 4°C, were obtained initially and on days 2, 5, and 9. Turbidity and pH measurements were performed in conjunction with visual observation on days of chromatographic analysis. Results demonstrate that sodium nitroprusside compounded in 5% dextrose at a concentration of 1 mg/mL, stored at 4°C protected from light in polypropylene syringes, is physically and chemically stable for at least 9 days.

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.