Methodology for the investigation of ignition near hot surfaces in a high-pressure shock tube

Autoignition of fuel/air mixtures is a determining process in internal combustion engines. Ignition can start either homogeneously in the gas phase after compression or in the vicinity of hot surfaces. While ignition properties of commercial fuels are conventionally described by a single quantity (octane number), it is known that some fuels have a varying propensity to the two processes. We present a new experimental concept that generates well-controlled temperature inhomogeneities in the shock-heated gases of a high-pressure shock tube. A shock-heated reactive mixture is brought into contact with a heated silicon nitride ceramic glow plug. The glow-plug temperature can be set up to 1200 K, higher than the post-reflected-shock gas temperatures (650-1050 K). High-repetition-rate chemiluminescence imaging is used to localize the onset of ignition in the vicinity of the hot surface. In experiments with ethanol, the results show that in most cases under shock-heated conditions, the ignition begins inhomogeneously in the vicinity of the glow plug and is favored because of the high wall temperature. Additionally, the interaction of geometry, external heating, and gas-dynamic effects was investigated by numerical simulations of the shock wave in a non-reactive flow.

Abstract P4-13-15: A retrospective head-to-head comparison between TiLoop Bra/TiMesh and seragyn in 320 cases of reconstructive breast surgery

Background: As an alternative option to ADMs (acellular dermal matrices) synthetic meshes are a cheaper and equally effective option in implanted breast reconstruction. However, clinical data concerning these synthetic meshes is limited. Also, direct comparisons between titanium-coated polypropylene mesh (TiLoop Bra/TiMesh) and partially absorbable polypropylene mesh (Seragyn) have not yet been reported. Therefore, this work will report clinical complication rate data on 320 cases of synthetic meshes TiLoop Bra/TiMesh and Seragyn.

Methods: This analysis represents a retrospective single surgeon multi-center study of 320 cases over 14 years (2003 until 2016) using either TiLoop Bra/TiMesh (n=192) or Seragyn (n=128) in breast reconstruction. Patient recruitment was consecutive. 124 cases of the TiLoop Bra /TiMesh cohort and 74 cases in the Seragyn cohort were oncological interventions. Results were correlated with ADM based reconstructions (Epiflex and SurgiMend) performed by the same surgeon.

Results: Major complication rates (i.e. revision surgery) occurred in 3.9 % (Seragyn) and 8.3 % (TiLoop Bra/TiMesh) of all cases. (not statistically significant). Minor complications (i.e. seroma requiring aspiration, infection requiring antibiotics, red breast syndrome/rash (RBS) and wound dehiscence occurred in 18 % (Seragyn) and 8.9 % (TiLoop Bra/TiMesh). Overall minor complication rates did also not differ statistically significant. However, subgroup analysis showed RBS to occur more often in the Seragyn group (3.9 % Seragyn vs. 0.5 % TiLoop Bra/TiMesh, p<0.05). A significant difference between SurgiMend and Epiflex compared to the synthetic meshes could also not been shown.

Conclusion: This retrospective analysis shows that titanium-coated polypropylene meshes like TiLoop Bra/TiMesh and partially absorbable meshes like Seragyn do not differ significantly in complication rates. Compared to the exponentially more expensive ADM alternatives complication rates did also not differ significantly. Synthetic meshes seem to be a cheaper and equally effective option.

Citation Format: Eichler C, Schulz C, Brunnert K, Mathias W. A retrospective head-to-head comparison between TiLoop Bra/TiMesh and seragyn in 320 cases of reconstructive breast surgery [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-13-15.

Shock-tube study of the decomposition of tetramethylsilane using gas chromatography and high-repetition-rate time-of-flight mass spectrometry

The decomposition of tetramethylsilane was studied in shock-tube experiments in a temperature range of 1270–1580 K and pressures ranging from 1.5 to 2.3 bar behind reflected shock waves combining GC/MS and HRR-TOF-MS.

Bluetongue virus serotype 27: Experimental infection of goats, sheep and cattle with three BTV-27 variants reveal atypical characteristics and likely direct contact transmission BTV-27 between goats

Bluetongue virus (BTV) hitherto consisted of 26 recognized serotypes, of which all except BTV-26 are primarily transmitted by certain species of Culicoides biting midges. Three variants of an additional 27th bluetongue virus serotype (BTV-27v01-v03) were recently detected in asymptomatic goats in Corsica, France, 2014-2015. Molecular characterization revealed genetic differences between the three variants. Therefore, in vivo characteristics were investigated by experimental infection of a total of 15 goats, 11 sheep and 4 cattle with any one of the three variants in separated animal trials. In goat trials, BTV-naïve animals of the same species were kept in a facility where direct contact was unhindered. Of the 15 inoculated goats, 13 and 14 animals were found positive for BTV-RNA and antibodies (Ab), respectively, until the end of the experiments. Surprisingly, BTV-Ab levels as measured with ELISA and neutralization test (SNT) were remarkably low in all seropositive goats. Virus isolation from whole-blood was possible at the peak of viremia until 49 dpi. Moreover, detection of BTV-27v02-RNA and Ab in one contact goat indicated that-similar to BTV-26-at least one of three BTV-27 variants may be transmitted by contact between goats. In the field, BTV-27 RNA can be detected up to 6 months in the whole-blood of BTV-27-infected Corsican goats. In contrast, BTV RNA was not detected in the blood of cattle or sheep. In addition, BTV-27 Abs were not detected in cattle and only a transient increase in Ab levels was observed in some sheep. None of the 30 animals showed obvious BT-like clinical signs. In summary, the phenotypes observed for BTV-27v01-v03 phenotypes correspond to a mixture of characteristics known for BTV-25 and 26.

An international study to revise the EORTC questionnaire for assessing quality of life in lung cancer patients

BACKGROUND

The European Organization for Research and Treatment of Cancer (EORTC) QLQ-LC13 was the first module to be used in conjunction with the core questionnaire, the QLQ-C30. Since the publication of the LC13 in 1994, major advances have occurred in the treatment of lung cancer. Given this, an update of the EORTC QLQ-LC13 was undertaken.

METHODS

The study followed phases I to III of the EORTC Module Development Guidelines. Phase I generated relevant quality-of-life issues using a mix of sources including the involvement of 108 lung cancer patients. Phase II transformed issues into questionnaire items. In an international multicenter study (phase III), patients completed both the EORTC QLQ-C30 and the 48-item provisional lung cancer module generated in phases I and II. Patients rated each of the items regarding relevance, comprehensibility, and acceptance. Patient ratings were assessed against a set of prespecified statistical criteria. Descriptive statistics and basic psychometric analyses were carried out.

RESULTS

The phase III study enrolled 200 patients with histologically confirmed lung cancer from 12 centers in nine countries (Cyprus, Germany, Italy, Israel, Spain, Norway, Poland, Taiwan, and the UK). Mean age was 64 years (39 - 91), 59% of the patients were male, 82% had non-small-cell lung cancer, and 56% were treated with palliative intent. Twenty-nine of the 48 questions met the criteria for inclusion.

CONCLUSIONS

The resulting module with 29 questions, thus currently named EORTC QLQ-LC29, retained 12 of the 13 original items, supplemented with 17 items that primarily assess treatment side-effects of traditional and newer therapies.

Reaction-time-resolved measurements of laser-induced fluorescence in a shock tube with a single laser pulse

Shock tubes allow for the study of ultra-fast gas-phase reactions on the microsecond time scale. Because the repetition rate of the experiments is low, it is crucial to gain as much information as possible from each individual measurement. While reaction-time-resolved species concentration and temperature measurements with fast absorption methods are established, conventional laser-induced fluorescence (LIF) measurements with pulsed lasers provide data only at a single reaction time. Therefore, fluorescence methods have rarely been used in shock-tube diagnostics. In this paper, a novel experimental concept is presented that allows reaction-time-resolved LIF measurements with one single laser pulse using a test section that is equipped with several optical ports. After the passage of the shock wave, the reactive mixture is excited along the center of the tube with a 266-nm laser beam directed through a window in the end wall of the shock tube. The emitted LIF signal is collected through elongated sidewall windows and focused onto the entrance slit of an imaging spectrometer coupled to an intensified CCD camera. The one-dimensional spatial resolution of the measurement translates into a reaction-time-resolved measurement while the species information can be gained from the spectral axis of the detected two-dimensional image. Anisole pyrolysis was selected as the benchmark reaction to demonstrate the new apparatus.

Use of LDH and autoimmune side effects to predict response to ipilimumab treatment

BACKGROUND

Ipilimumab is a cytotoxic T-lymphocyte antigen-4 antibody that enhances T-cell activity and proliferation.

METHODS

In a retrospective analysis of 86 patients the clinical benefits of ipilimumab treatment were correlated with laboratory and clinical data.

RESULTS

A lactate dehydrogenase (LDH) value within the normal range before the start of therapy was significantly correlated with better OS (p ≤ 0.009). An increase in LDH level after two cycles was indicative of a poor outcome, and was significantly negatively correlated with treatment response and overall survival and progression-free survival. 42% of all patients suffered from autoimmune toxicity (CTCAE grades 2-4). The occurrence of autoimmune toxicity clearly correlated with clinical benefit.

CONCLUSION

Changes in LDH level and side effects correlate with response to therapy and survival.

Uncertainty quantification and design-of-experiment in absorption-based aqueous film parameter measurements using Bayesian inference

Diode laser-based multi-wavelength near-infrared (NIR) absorption in aqueous films is a promising diagnostic for making temporally resolved, simultaneous measurements of film thickness, temperature, and concentration of a solute. Our previous work in aqueous urea solutions aimed at determining simultaneously two of these system parameters, while the third one must be fixed or specified by additional measurements. The current work presents a simultaneous NIR absorption-based multi-parameter measurement of thickness, temperature, and solute concentration coupled with the Bayesian methodology that is used to infer probability densities for the obtained data. The Bayesian analysis is based on a temperature- and concentration-dependent spectral database generated with a Fourier transform infrared spectrometer in the range 5500-8000  cm^-1 for water with variable temperature and urea concentration. The concept was first validated with measurements using a calibration cell. Probability densities in the measured parameters were quantified using a Markov chain Monte Carlo algorithm, which were used to derive credibility intervals. As a practical demonstration, the temporal variation of film thickness, urea concentration, and liquid temperature were recorded during evaporation of a liquid film deposited on a transparent heated quartz plate.

[Near-infrared spectroscopy for the detection of traumatic intracranial hemorrhage: Feasibility study in a German army field hospital in Afghanistan]

Traumatic brain injury (TBI) is one of the most common causes of death in ordinary accidents, natural disasters, or warfare. The gold standard for diagnosis of TBI is the CT scan; a delay of diagnostics or medical care is the strongest independent predictor of mortality of TBI patients--particularly in the case of a surgically treatable intracranial hematoma. The proper classification of these patients is of major importance in situations where a CT is not accessible. A portable screening device that uses near-infrared spectroscopy (NIRS) technology allows a preliminary estimate of an intracranial hematoma. This study assessing practicability shows that the use of the device in a military medical rescue center (Kunduz, Afghanistan) is easy to learn and can be repeatedly used even under emergency room conditions. The technique can be applied in penetrating and blunt TBIs in the absence of an immediately available CT scan in rural areas, preclinically, under mass casualty conditions (e.g., in disaster situations) as well as in humanitarian crises or war zones. Nevertheless, further studies to assess the validity of this device are necessary.

A single-pulse shock tube coupled with high-repetition-rate time-of-flight mass spectrometry and gas chromatography for high-temperature gas-phase kinetics studies

Shock tubes are frequently used to investigate the kinetics of chemical reactions in the gas phase at high temperatures. Conventionally, two complementary arrangements are used where either time-resolved intermediate species measurements are conducted after the initiation of the reaction or where the product composition is determined after rapid initiation and quenching of the reaction through gas-dynamic processes. This paper presents a facility that combines both approaches to determine comprehensive information. A single-pulse shock tube is combined with high-sensitivity gas chromatography/mass spectrometry for product composition and concentration measurement as well as high-repetition-rate time-of-flight mass spectrometry for time-dependent intermediate concentration determination with 10 μs time resolution. Both methods can be applied simultaneously. The arrangement is validated with investigations of the well-documented thermal unimolecular decomposition of cyclohexene towards ethylene and 1,3-butadiene at temperatures between 1000 and 1500 K and pressures ranging from 0.8 to 2.4 bars. The comparison shows that the experimental results for both detections are in very good agreement with each other and with literature data.

[Large Hibernoma of the Proximal Upper Arm and the Axilla - Literature Review and Case Description of a Very Rare Benign Soft Tissue Tumor]

Hibernomas are very rare benign soft tissue tumors arising from brown fat. Malignant transformation or metastases are unknown. Males seems to be affected more often. Most patients are aged 20 to 40, but patients with intraosseous hibernomas are older. In children, hibernomas are extremely rare. The tumors grow slowly and have usually been present for a few years on presentation. Hibernomas are typically located on the thigh, neck, axilla or in the peri- und interscapular region. Diagnostic work-up in symptomatic hibernomas usually includes conventional X-ray and magnetic resonance tomography (MRI) with contrast medium. Asymptomatic hibernomas are often found accidentally in the diagnostic work-up of other diseases. Important differential diagnoses are lipomas, well differentiated liposarcomas, rhabdomyomas, granular cell tumors and sebeceous adenomas. Incisional biopsy should be performed to allow definitive histological diagnosis before definitive therapy. According to the literature, histologically preserved hibernomas can be removed with curative intention and marginal resection. After complete tumor removal, local recurrence has not been described. The following article describes the case of a large hibernoma of the proximal arm, involving the axilla, and describes the epidemiology, clinical behavior, diagnostic work-up, therapy and prognosis of this very rare benign fatty soft tissue tumor, on the basis of a review of current literature.