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Plenty of publications have highlighted differences in individual physical or chemical properties of emitted diesel particulate matter (PM) and have correlated them to soot reactivity. An overview is given in the first part of the paper. Our study presented in the second part includes the determination of physical and of chemical properties of the emitted PM, which was generated at different boost and injection pressures on a modern light-duty diesel engine. The individual properties have been opposed to the reactivity of the PM. Afterwards, these correlations are discussed. The experiments show wide-ranging distinctions in soot reactivity (up to 162 °C). The determined differences in soot structures as well as in primary particle sizes are small and do not correlate clearly to soot reactivity. Hence, there has to be a further property which influences soot reactivity to a high extent. PM composition (oxygen, ash content) is identified as a further property impacting soot reactivity. The various ash contents show good correlations to the soot oxidation behavior. The distinctions in ash contents can be explained by the different sampling durations because of large changes in emitted particulate mass, due to the high differences in particle size and number emissions. The source of the ash (Ca, Zn, Al) is attributed to inorganic elements from fuel, lubricating oil and engine wear. In addition, the oxygen content in soot is a further chemical property impacting soot reactivity.

Since the EU demands the use of renewable energy sources, also in the transport sector, the usage of biodiesel fuels increases continuously. As the physicochemical properties of soot are important for the oxidation behavior during the regeneration of diesel particle filters (DPF) and literature provides contradictory information about the reactivity and the structure of biodiesel soot, the aim of this work was to investigate the reactivity of soot produced by a diesel engine operated with fuels of different biodiesel content at varying engine operating parameters. By temperature-programmed oxidation (TPO) an increasing reactivity with increasing biofuel ratio, except for the conditions with lowest injection pressure was determined. This implies that soot generated with 100% biofuel (consisting of rapeseed oil methyl ester) is more reactive than soot generated with commercial gasoline station fuel containing up to 7% biodiesel, while soot from fossil fuel is even less reactive. In addition, reactivity increases with increasing injection and boost pressure. Raman microspectroscopy (RM) analysis gave very similar spectra for the received soot samples, i.e. all generated soot samples possess a similar graphitic nanostructure. Additionally, a trend in reactivity with the particle size as well as the content of Fe, Zn, and Cu in the soot, which was determined by inductively coupled plasma mass spectrometry (ICP-MS), could be revealed. The soot reactivity is therefore not only determined by one parameter but a product of many soot properties like nanostructure, particle size and/or inorganic components as impurities. When following the structural change in the DPF during regeneration, a decreased structural order was observed in the beginning. After a certain time (ca. 40 s) a homogeneous oxidation of the soot takes place, which does not change the structure of the soot inside the DPF. This coincides with findings of a constant oxidation rate after a certain time. Overall, it can be ascertained that no graphitization of the soot takes place inside the DPF during regeneration.

Das Verstaendnis der Russreaktivitaet stellt eine wichtige Basis fuer die effiziente Regeneration des eingelagerten Russes im Dieselpartikelfilter (DPF) im Betrieb mit unterschiedlichen biogenen Kraftstoffen dar. In einem FVV-FNR-Forschungsvorhaben wurde mit unterschiedlichen Analyseverfahren der Zusammenhang zwischen der Reaktivitaet und den physikochemischen Eigenschaften unterschiedlicher Dieselrusse untersucht sowie deren Abbrandverhalten im DPF modelliert. Es zeigte sich, dass die Russreaktivitaet mit steigendem Biodieselanteil bei der aktiven Regeneration zunimmt, waehrend die Mikrostruktur der Russe nahezu identisch ist. Die unterschiedliche Russreaktivitaet laesst sich bei den untersuchten Proben nicht ueber die Russmikrostruktur erklaeren. Jedoch konnte festgestellt werden, dass die Reaktivitaet mit dem Gehalt an Cu, Fe und Zn im Russ eine gewisse Uebereinstimmung zeigt. Daraus kann geschlossen werden, dass die Russreaktivitaet nicht nur von einem Parameter, sondern von der Summe vieler Russeigenschaften wie Mikrostruktur, Partikelgroesse sowie Ascheanteil bestimmt wird. Zudem deuten die Ergebnisse darauf hin, dass der Anteil der einzelnen Aschekomponenten unterschiedlichen Einfluss auf die Reaktivitaet der Russe hat. Ausserdem wurde mithilfe von isothermen Messungen festgestellt, dass der Reaktivitaetsvorteil des Biodiesels fuer passive Regenerationsbedingungen nicht auftritt. Bei der aktiven Regeneration nimmt dieser zudem mit steigender Temperatur ab. Bei allen untersuchten Russarten ist die Reaktivitaet zu Beginn der Regeneration deutlich erhoeht. (A)

Leaner burning and downsizing are two concepts pursued by engine developers to reduce fuel consumption and emissions. Both approaches lead to increasing challenges concerning ignition, as these concepts are typically associated with an increase in flow velocity and degree of turbulence as well as raised pressure at the moment of ignition. In this context, the use of miniaturized passively Q-switched laser spark plugs with pulse train ignition is considered as a promising alternative to conventional spark plugs. However, the application of these passively Q-switched laser spark plugs inevitably leads to the question of optimum pulse train parameters. For a better understanding, this study deals with improved flame formation by passively Q-switched laser pulse train ignition under engine-like conditions. The entire ignition process is investigated with a special focus on interactions of consecutive pulses. Therefore, three methods are combined: energy transfer measurements from laser pulse to plasma with high temporal and spatial resolution show the breakdown process depending on different pressures and fluid mixtures. The temperature decrease in the induced plasma is analyzed with measurement strategies for temporal high-resolved plasma spectroscopy especially adapted to passively Q-switched lasers. In combination with high-speed schlieren measurements, the changing local ignition conditions during pulse train ignition are demonstrated. The experiments show how consecutive pulses interact and contribute to the ignition in case of a gas flow. The used prototypes of laser spark plugs are provided by Robert Bosch GmbH.

Heinrich von Pfalzpaint (circa 1415-1465) was a Bavarian military surgeon of the Teutonic Order who treated more than 4000 casualties during the siege of Marienberg Fortress (1454-1457). In 1460, he reported "How to create a new nose if it has been chopped off and the dogs have eaten it" in his treatise on wound care Bundt-Ertznei. He used opium-soaked sponges for anesthesia, described the surgical extraction of bullets and cleft lip repair. Pfalzpaint would have been the first author to describe nasal reconstruction in Europe if his treatise had not been lost. Only 5 copies of his manuscript existed. One was rediscovered and printed in 1868. Pfalzpaint's technique for nasal reconstruction was performed in 2 stages using an undelayed skin flap from the upper arm, which was sutured to the nasal defect and the arm was bandaged to the head. After 8 to 10 days, he divided the pedicle; inset the flap; and fashioned the nasal dorsum, alae, and columella. Tagliacozzi described arm flap nasal reconstruction more than a century later in 1597. He used delayed skin flaps, with at least 6 operative stages over 4 months. Pfalzpaint was ahead of his time regarding his knowledge of wounds, insistence on surgical cleanliness, and his technically easier arm flap rhinoplasty, compared with Tagliacozzi. Pfalzpaint, who is rarely referenced in the literature, should be remembered as a great pioneer of reconstructive surgery in Europe.

OBJECTIVEAlthough rare, frontoethmoidal meningoencephaloceles continue to pose a challenge to neurosurgeons and plastic reconstructive surgeons. Especially when faced with limited infrastructure and resources, establishing reliable and safe surgical techniques is of paramount importance. The authors present a case series in order to evaluate a previously proposed concise approach for meningoencephalocele repair, with a focus on sustainability of internationally driven surgical efforts.METHODSBetween 2001 and 2016, a total of 246 patients with frontoethmoidal meningoencephaloceles were treated using a 1-stage extracranial approach by a single surgeon in the Department of Neurosurgery of the Yangon General Hospital in Yangon, Myanmar, initially assisted by European surgeons. Outcomes and complications were evaluated.RESULTSA total of 246 patients (138 male and 108 female) were treated. Their ages ranged from 75 days to 32 years (median 8 years). The duration of follow-up ranged between 4 weeks and 16 years (median 4 months). Eighteen patients (7.3%) showed signs of increased intracranial pressure postoperatively, and early CSF rhinorrhea was observed in 27 patients (11%), with 5 (2%) of them requiring operative dural repair. In 8 patients, a decompressive lumbar puncture was performed. There were 8 postoperative deaths (3.3%) due to meningitis. In 15 patients (6.1%), recurrent herniation of brain tissue was observed; this herniation led to blindness in 1 case. The remaining patients all showed good to very good aesthetic and functional results.CONCLUSIONSA minimally invasive, purely extracranial approach to frontoethmoidal meningoencephalocele repair may serve well, especially in middle- and low-income countries. This case series points out how the frequently critiqued lack of sustainability in the field of humanitarian surgical missions, as well as the often-cited missing aftercare and dependence on foreign supporters, can be circumvented by meticulous training of local surgeons.

Arhinia, or absence of the nose, is a rare malformation of unknown etiology that is often accompanied by ocular and reproductive defects. Sequencing of 40 people with arhinia revealed that 84% of probands harbor a missense mutation localized to a constrained region of SMCHD1 encompassing the ATPase domain. SMCHD1 mutations cause facioscapulohumeral muscular dystrophy type 2 (FSHD2) via a trans-acting loss-of-function epigenetic mechanism. We discovered shared mutations and comparable DNA hypomethylation patterning between these distinct disorders. CRISPR/Cas9-mediated alteration of smchd1 in zebrafish yielded arhinia-relevant phenotypes. Transcriptome and protein analyses in arhinia probands and controls showed no differences in SMCHD1 mRNA or protein abundance but revealed regulatory changes in genes and pathways associated with craniofacial patterning. Mutations in SMCHD1 thus contribute to distinct phenotypic spectra, from craniofacial malformation and reproductive disorders to muscular dystrophy, which we speculate to be consistent with oligogenic mechanisms resulting in pleiotropic outcomes.

International audience; Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD.

Lean combustion and downsizing are two concepts to increase fuel efficiency and to reduce emissions of engines. However, the requirements on the ignition system increase consequently due to increased flow velocity and pressure at the time of ignition. In this context, the application of miniaturized passively q-switched laser spark plugs with pulse train operation provides an alternative to the conventional spark plug. To exploit the full potential of the pulse trains, ignition and combustion processes induced by passively q-switched laser spark plugs are investigated in this study.

Multimedia streaming applications are traditionally delivered over UDP. Recent measurements show that more and more multimedia streaming data are over TCP as web-based TV, P2P streaming, video sharing websites are getting increasingly popular. To improve the quality of experience (QoE) for users and to cope with variability in TCP throughput, streaming applications typically implement buffers. Yet, for improving the QoE and the streaming quality, e.g., playback continuity and timeliness, it is critical to dimension buffers and the initial buffering delay appropriately. In this paper, we first develop a model for TCP streaming systems and an analytical framework to assess the QoE. Our emphasis is on buffer occupancy, which depends on the TCP arriving rate and the playout rate (the coding rate). We observe that TCP window “bounds”, namely congestion window sizes immediately before a triple duplicate or timeout event, allow to distinguish the minimum and maximum buffer occupancy for TCP streaming systems. As confirmed by experiments, the proposed analytical framework allows to estimate the frequency of buffer overflow or underflow events if buffer sizes and the initial buffering delays are known parameters, or conversely, to dimension the buffer and delay appropriately. We further extend our model and analysis for P2P multicast streaming systems. Simulations and experiments in real networks validate our proposed analytical framework in terms of underflow/overflow probabilities and delay.

Autonomous system (AS) business relationships and their inference have been widely studied by network researchers in the past. An important application of inferred AS relationships can be the prediction of AS paths between a source and destination AS within a model. However, besides knowing the topology and inferred AS relationships, AS path prediction within a model needs to be understood in order for us to know how we can derive border gateway protocol (BGP) policies from AS relationships. In this paper, we shed light onto the predictive capabilities of AS relationships by investigating whether they can be translated into BGP policies such that inferred AS paths are consistent with real AS paths, e.g., paths observed from BGP routing tables. Our findings indicate that enforcing constraints such as the well-known valley-free property and the widely assumed preference of customer routes always results in a very low consistency for AS path inference. In addition, this is true irrespective of whether customer, peer, or provider routes are preferred. Apparently, applying such constraints eliminates many “correct” paths that are observed in BGP routing tables and that are propagated in a simple shortest path model where AS relationships are ignored. According to our findings, deriving BGP routing policies for predicting with high accuracy AS paths in a model directly from AS relationships is still difficult.

Physical and chemical properties of emitted soot particles are influenced by diesel engine operating parameters. In order to find correlations between the in-cylinder processes of combustion and the engine-out properties of soot particles, parameter studies were carried out on a modern light duty production diesel engine (turbo direct injection, TDI) and an optically accessed single cylinder diesel engine (single cylinder). Several techniques have been combined to analyze the combustion process as well as the emitted particles. The size of emitted soot particles of the TDI engine has been determined by a scanning mobility particle sizer (SMPS), and soot samples have been analyzed by a high-resolution transmission electron microscope (HR-TEM) and by thermogravimetry (TG). In addition, the internal combustion in an optically accessed single cylinder engine has been observed by time resolved spectroscopy as well as OH*- and C2-imaging. It turns out that in both cases, increasing injection pressure leads to a...

Internet disruptions such as the Northeast Blackout (2003) and the Taiwan earthquake (2006) highlight the fragility of today’s Internet. Our goal in this paper is to investigate the robustness of inter-domain communication at the level of autonomous systems (ASes), taking into account both topological connectivity and compliance to routing policies. To this end, we introduce the concept of k-fault tolerance for Type-of-Relationship (ToR) graphs, which requires that any two nodes (ASes) remain reachable from each other even after removing arbitrary k nodes from the AS graph. Our main contribution is theoretical and concerns the complexity of the k-fault tolerance decision problem. Drawing on strong evidence about the hierarchical structure of the Internet AS graph, we derive sufficient and necessary conditions for determining whether the graph is k-fault tolerant or not in polynomial time. We then apply this theoretical result to study the network-wide resilience properties of AS-level topology instances, as inferred from large-scale experimental data sets. We find that even single-node failures can disconnect up to hundred of ASes and that approximately 1500 ASes do not avail any real redundancy for their global reachability despite having two or more upstream links. Augmenting AS-level graphs for 1-fault tolerance improves overall resilience to failures, but requires a considerable number of AS-level edges (>7000) to be added. Interestingly, such additional upstream links are mainly needed at stub networks rather than at transit ASes, pointing out the need for multi-homing at stub networks.

Internet routing table size growth and BGP update churn are two prominent Internet scaling issues. There is widespread belief in a high and fast growing number of ASs that deaggregate prefixes, e.g., due to multi-homing and for the purpose of traffic engineering. Moreover, researchers often blame specific classes of ASs for generating a disproportionate amount of BGP updates. Our primary objective is to challenge such widespread assumptions (“myths”) and not solely to confirm previous findings. Surprisingly, we find severe discrepancies between existing myths and reality. According to our results, there is no trend towards more aggressive prefix deaggregation or traffic engineering over time. With respect to update dynamics, we observe that deaggregated prefixes generally do not generate a disproportionate number of BGP updates, with respect to their share of the BGP routing table. On the other side, we observe much more widespread traffic engineering in the form of AS path prepending and scoped advertisements compared to previous studies. Overall, our work gives a far more positive picture compared to the alarming discourses typically heard: The impact of “bad guys” on routing table size growth and BGP churn has not changed for the worse in recent years. Rather, it increases at the same pace as the Internet itself.

Years after the initial development of the current routing protocols we still lack an understanding of the impact of various parameters on the routes chosen in today's Internet. Network operators are struggling to optimize their routing, but the effectiveness of those efforts is limited. In this article, we study sensitivity of routing stretch and diversity metrics to factors such as policies, topology, IGP weights, etc. using statistical techniques. We confirm previous findings that routing policies and AS size (in number of routers) are the dominating factors. Surprisingly, we find that intra-domain factors only have marginal impact on global path properties. Moreover, we study path inflation by comparing against the paths that are shortest in terms of AS-level/router-level hops or geographic distances. Overall, the majority of routes incur reasonable stretch. From the experience with our Internet-scale simulations, we find it hard to globally optimize path selection with respect to the geographic length of the routes, as long as inter-domain routing protocols do not include an explicit notion of geographic distance in the routing information.

The ignition process of different prototypes of passively Q-switched laser spark plugs was investigated. Energy transfer, plasma temperature, shock wave and flame kernel formation were analyzed considering the effect of laser pulse trains and fluid flow.

Background: Ever since Charles Baxter's recommendations the standard regime for burn shock resuscitation remains crystalloid infusion at a rate of 4 ml/kg/% burn in the first 24 h following the thermal injury. A growing number of studies on invasive monitoring in burn shock, however, have raised a debate regarding the adequacy of this regime. The purpose of this prospective, randomised study was to compare goal-directed therapy guided by invasive monitoring with standard care (Baxter formula) in patients with burn shock. Patients and methods: Fifty consecutive patients with burns involving more than 20% body surface area were randomly assigned to one of two treatment groups. The control group was resuscitated according to the Baxter formula (4 ml/kg BW/% BSA burn), the thermodilution (TDD) group was treated according to a volumetric preload endpoint (intrathoracic blood volume) obtained by invasive haemodynamic monitoring. Results: The baseline characteristics of the two treatment groups were similar. Fluid administration in the initial 24 h after burn was significantly higher in the TDD treatment group than in the control group ( P = 0.0001). The results of haemodynamic monitoring showed no significant difference in preload or cardiac output parameters. Signs of significant intravasal hypovolemia as indicated by subnormal values of intrathoracic and total blood volumes were present in both treatment groups. Mortality and morbidity were independent on randomisation. Conclusion: Burn shock resuscitation due to the Baxter formula leads to significant hypovolemia during the first 48 h following burn. Haemodynamic monitoring results in more aggressive therapeutic strategies and is associated with a significant increase in fluid administration. Increased crystalloid infusion does not improve preload or cardiac output parameters. This may be due to the fact that a pure crystalloid resuscitation is incapable of restoring cardiac preload during the period of burn shock.

Abdominoplasty procedures involve a high risk of early complications, including hematomas, seromas, necrosis, and wound-healing problems. Their rationale is evident from the vascular anatomy of the abdominal wall, as traditional abdominoplasty includes a division of the main perforating vessels. No studies exist to quantitatively assess the consequences of abdominoplasty on the perfusion of the random pattern abdominal flap. To address this issue and quantify the influence of classic abdominoplasty on the perfusion of the abdominal skin, the authors performed a prospective clinical trial including 15 low-risk patients undergoing abdominoplasty for aesthetic purposes. Perfusion of the abdominal flap was measured intraoperatively using the technique of dynamic laser-fluorescence-videoangiography. In the region between the umbilicus and the transverse scar (zone 1), the increment of fluorescence (the slope of the intensity curve during inflow of the indocyanine green) was recorded and compared with the intensity curve of normal tissue that was not involved in surgery (thoracic wall). The results of the intraoperative indocyanine green perfusography showed a significant impairment of the vascular supply of zone 1 in all patients. The mean perfusion index in this region was 17.2 percent (range, 5 to 32 percent) of the perfusion of the surrounding skin that was not involved in surgery. The complication rate was 33 percent (five patients) and included two cases of hematoma and three cases of scar dehiscence with skin and/or fat necrosis. These data indicate that conventional abdominoplasty including extended undermining and division of the superficial and the deep arterial systems causes profound devascularization of the abdominal flap. This might explain the high incidence of complications following this procedure.

Hyperglycaemia and insulin resistance are common in severely burned patients, even if they have not previously had diabetes. Conventionally, hyperglycaemia is considered a part of the hypermetabolic stress response and blood glucose levels up to 215 mg/dl are tolerated before insulin therapy is initiated. Recent studies suggest that hyperglycaemia and insulin resistance are harmful and that correcting blood glucose to normal levels with insulin might improve the prognosis significantly.The purpose of this clinical study was to evaluate blood glucose levels in severely burned patients with conventional management and to analyse the association between early hyperglycaemia and clinical outcome.Clinical, prospective, descriptive study.Thirty seven severely burned adults (25% total body surface area).Hyperglycaemia was treated according to conventional clinical practice. This included the infusion of insulin based on a blood glucose level215 mg/dl and the maintenance of the glucose level between 180 and 200 mg/dl.Measurements of whole-blood glucose were performed at 8, 16, 24, 36 and 48 h after the thermal injury. Additional measurements were performed if indicated. A total of 185 measurements were obtained and significant elevations of blood glucose levels (140 mg/dl) were found in 108 (64%) of the measurements. Peak blood glucose values exceeded 140 mg/dl in all but three of the patients; however, only 17 patients received insulin treatment during the shock period. The inadequacy of the insulin treatment is shown by the mean glucose values, which exceeded 200 mg/dl in 27% of the patients. Despite a non-significant difference in the extent of burn (P=0.055), patients who died showed significantly higher maximum glucose values than patients who survived the thermal injury (P0.05). Even though not statistically significant, blood glucose control was poorer in patients who later developed sepsis or acute renal failure (P0.05). No correlation was found between burned surface area (TBSA) and mean plasma glucose levels during the first 48 h of resuscitation (r=0.12).Hyperglycaemia is very frequent during the resuscitation period of thermal injury and current guidelines for insulin therapy are inadequate to correct plasma glucose to normal levels. As an association between early hyperglycaemia and subsequent mortality seems to exist, more aggressive manoeuvres to reduce blood glucose may be warranted in this group of patients.

The objective assessment of tissue perfusion is of utmost importance to plastic surgeons. Nevertheless, clinical observation remains the accepted gold standard for assessment of microcirculation. Dynamic laser fluo- rescence videography is a new technique for objective assessment of blood flow. We describe our clinical expe- rience using this technique in plastic surgical patients. Possible implementations include evaluation of pedicle (random and axial pattern) flaps, monitoring of free tis- sue transfer and replants, and the objective determination of burn depth. Compared with standard clinical assess- ment techniques indocyanine green imaging provides significant additional information which allows a ratio- nal and evidence-based planning of surgery.

Study objective Arterial thermal dilution with an integrated fiberoptic monitoring system (COLD Z-021; Pulsion Medical Systems; Munich, Germany) allows measurement of extravascular lung water (EVLW) and pulmonary permeability index (PPI). The aim of this study was to evaluate the widespread clinical assumption that early respiratory failure following burn and inhalation injury is due to interstitial fluid accumulation in the lung. Design Clinical, prospective study. Setting ICU of a university referral center of burn care. Patients Thirty-five severely burned adults (> 20% of body surface area). Interventions Resuscitation therapy was guided by the results of hemodynamic monitoring using the intrathoracic blood volume (ITBV) as a cardiac preload indicator. The resuscitation goals included a normalization of preload (ITBV > 850 mL/m 2 ) and cardiac index (> 3.5 L/min/m 2 ) within 24 h after ICU admission. Fluid loading was implemented to reach these goals. Measurements and results One hundred forty lung water measurements were performed at 0 h, 12 h, 24 h, and 48 h after admission to the ICU. Significant elevation of EVLW and PPI was found in three measurements (2%) at 48 h after ICU admission, and was in one patient associated with inhalation injury. EVLW and PPI were not significantly different between patients with and without inhalation injury. No correlation was found between resuscitation volume and EVLW ( r 2 = 0.02) or between the alveolar-arterial oxygen pressure difference and EVLW ( r 2 = 0.017). Chest radiograph abnormalities were found in 2 of 22 patients with inhalation injury; these were not associated with increased values of EVLW. Conclusion Early fluid accumulation in the lung in burned patients is very uncommon, even in the presence of inhalation injury. There is no evidence that thermal injury causes an increase in pulmonary capillary membrane permeability.

In a prospective, clinical study, the clinical utility of indocyanine green for intraoperative monitoring of free tissue transfer was evaluated. The study comprised 20 surgical patients undergoing elective microsurgical procedures. Indocyanine green angiography was performed intraoperatively, immediately after flap inset, and the operating team was blind to the fluoremetric findings. Thereafter, postoperative monitoring was done exclusively by clinical examination (color, temperature, time for recapillarization, and bleeding after puncture). Final outcome was compared with results of perioperative indocyanine (ICG)-imaging, and classified either as total flap loss, partial flap loss, or successful tissue transplantation. A total of 2 (10%) complications was recorded, and included one partial and one total flap loss. Both complications were detected by intraoperative ICG imaging. Another case of intraoperative subclinical arterial spasm at the place of microvascular anastomosis was revealed by dynamic ICG-videography. This flap did not develop postoperative complications. In conclusion, evaluation of perfusion by ICG imaging is feasible in all kinds of microsurgical flaps, irrespective of the type of tissue. Even though not meeting all the criteria of an ideal monitoring device, significant additional information can be obtained. In this study, cases with arterial spasm, venous congestion, and regional hypoperfusion were revealed by intraoperative ICG-videography. There was a strong correlation between intraoperative findings and clinical outcome.

proach for Hemodynamic Monitoring of Burn Shock. The pathophysiologic changes following thermal injury exceed those of any other trauma we know. Myocardial depression, capillary leakage and extravascular edema lead to hemodynamic collapse and organ failure, if not adequately treated. Being able to objectively measure these extreme fluid shifts would allow an individually based fluid treatment instead of the traditional, formula based shock therapy. The transpulmonary thermodilution (TPID) allows an individually based burn resuscitation, which uses measurements of intravascular volume deficits as guide for fluid therapy. This technique utilizes a computerized analysis of double-indicator (temperature and dye) dilution, and has been successfully used to manage the therapy of critically ill patients, especially following cardiac surgery. The technique requires only a central venous catheter and an arterial fiber optic thermistor catheter inserted into the femoral artery. TPID determines the intrathoracic blood volume that has been shown to reflect circulatory filling and volume status more precisely than CVP and PCWP. Additionally extravascular lung water can be determined, which may offer a precise estimation of the interstitial water in the lung. This allows a rational substitution of fluid during burn shock; restoring intravascular volumes while being able to monitor the interstitial fluid of the lung to avoid pulmonary edema. The aim of this article is to provide an introduction to the basic principles of TPID and an evaluation of our experience with this technique for guidance of shock therapy of severely burned patients.

Study objective: To study the agreement between cardiac output measurements with the pulmonary artery catheter and with the transpulmonary thermodilution technique in patients with burns. Design: Prospective, clinical study. Patients: 23 patients with serious burns and an abbreviated burn severity index score (ABSI)>6. Setting: intensive care unit for severely burned in a burn center in Germany. Results: A total number of 218 cardiac output measurements obtained during the first 72 h postburn were analysed. In the pulmonary artery group, mean cardiac index was 3.93 l/min/m2 and ranged from 0.96 to 9.58. In the transpulmonary group the cardiac index measurements ranged from 0.96 to 9.61 with a mean of 4.0 l/min/m2. During the entire observation period cardiac index was consistently higher in the transpulmonary group than in the pulmonary artery group with a bias of 0.32 l/min/m2 and a standard deviation (S.D.) of 0.29 l/min/m2. Linear regression analysis revealed CIarterial=0.98×CIpulm+0.22l/min/m2 (r=0.9678, P

PURPOSE: To assess the viability of cultured epithelium and preserved by freezing for periods varying from one month to one year. METHODS: Samples of cultured epithelium were incubated in cryoprotectant medium (Group A), packed in aluminum envelopes and packed in polystyrene boxes. The boxes were subjected to a temperature of-70oC. After freezing for a period of time ranging from one to 12 months, cultured epithelial samples were assessed for their viability by vital staining (Trypan blue) and metabolic analysis based on glucose consumption and lactate production. Samples of not frozen cultured epithelium (Group B) were also tested for viability and the results obtained were used as comparison parameter for the variation of viability. RESULTS: Statistical analysis between the group A and B indicate that the mean age of the donors (p=0.51) and the culture time (p=1.18) showed no statistical difference. In 30 days we obtained 37% of the original viability of cultured epithelium, 25% at six months and one year, less than 15%. This trend was confirmed statistically with a reduction of approximately 1.8% of the original viability epithelium cultured every 30 days of storage. In the analysis by lactate production, similar results were observed. In the analysis by the glucose consumption results were not significant. The viability indices show statistically significant difference between the group A and B (p

A retrieval study was performed on implants placed extraorally in the craniofacial region. The study included 19 implants retrieved from 16 patients. The implants were all stable at the time of removal. For various reasons, 5 of the implants were never loaded, whereas 14 of the implants had a known loading period of 3 months to 7 years 7 months. The reasons for removal varied but included the following: death in 1 case; poor results of the bone-anchored hearing aid in 7 cases; host-related reasons, varying from soft tissue irritation to infection or pain, in 6 cases; change of treatment plan in 1 case; and scheduled direct removal at the time of insertion in 1 case. The results of the histologic evaluation were similar to those reported in retrieval studies of a corresponding design used intraorally.

Acute renal failure (ARF) is a well known complication of severe burns and is an important factor leading to an increase in mortality. In order to analyze possible pathogenetic and prognostic factors associated with ARF in burned patients we reviewed in a retrospective study the files of 328 patients with burns > 10% body surface area (BSA), admitted to our burn unit between 01.01.94 and 01.05.98. We found 48 patients with acute renal failure corresponding with an incidence of 14.6%. Patients with ARF had a mean burned surface area of 48% (13-95) and an abbreviated burn severity index score (ABSI) of 9.8 (4-15). Thirty eight (79%) of these patients had an inhalation injury diagnosed. Renal insufficiency was divided in a late and an early form depending on its time of onset and we found 15 (31%) patients with ARF occurring within the first 5 days of the hospital stay and 33 (69%) patients with ARF developing >5 days following the thermal injury. The incidence of myoglobinuria and hypotension during the resuscitation phase was significantly higher in the group with early ARF, whereas patients with late ARF presented sepsis more frequently than patients with early occurring renal failure. Accordingly, potential nephrotoxic antibiotics were administered more often in patients with late ARF. Patients with ARF were treated by continuous arteriovenous hemofiltration (CAVH) for a mean period of 10.5 days (1-47) and CAVH was associated with a complication rate of 10%. Most of the complications were associated with the vascular access in the femoral artery. The mortality rate in patients with ARF was 85% and death was due to multiple organ failure in 83% of the cases. Only burned BSA and inhalation injury proved to be significantly correlated with the development of ARF, whereas age, third degree burn or electric injury were not significantly different between the two groups. Neither age, TBSA, day of onset of ARF nor duration of the renal replacement therapy proved to be significantly different comparing survivors with non-survivors, and thus predictive for the survival rate.

Ocassionally a patient asks for correction of his asymmetric eyelids. In many instances, however, a careful analysis reveals that the actual cause is an asymmetry of the eyebrows. Generally, asymmetric eyebrows are due to excessive muscle dynamics (i.e., a hyperkinesia of the frontalis or the depressor supercilii muscles). Therefore, the asymmetry will not be corrected by an asymmetric blepharoplasty, which will instead disclose the preexisting asymmetry, much to the concern of the patient. Management of the asymmetric brow is demanding and requires a preoperative problem-oriented and detailed analysis of the individual patient to achieve satisfactory results. We present 10-years' experience using a problem-specific approach. This included intramuscular botulinum toxin A injection, superselective neurotomy, endoscopic browlift and traditional procedures such as the coronal and direct browlift. Indication, patient selection, results, and complications are discussed.