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The Roll-Out Solar Array (ROSA) is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors while still packaging efficiently. The ROSA flight experiment was launched to the International Space Station (ISS) on June 3rd, 2017 as a part of the eleventh SpaceX commercial resupply mission. After two weeks of storage, ROSA was extracted from the Dragon spacecraft, deployed, and put through a week of tests to verify its structural characteristics as well as the performance of photovoltaics. The structural dynamics experiments included active excitation of out-of-plane bending modes, and a study of the thermal-structural interaction of the structure during day-night transitions. Data was gathered from a small number of accelerometers located at key points on the solar array and from cameras observing numerous photogrammetry targets spread out over the structure and the photovoltaic blanket. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays. Of particular interest are the first few system modes and mode shapes of the array, the amount of structural damping present, and degree of structural-thermal interaction seen during eclipse exit.

Die pharmakologische Behandlung von Schwangeren und Stillenden ruft nicht selten Angst und Verunsicherung hervor, die zu einer Nichtgabe eines notwendigen sicheren Praparats, einer insuffizienten Therapie oder zum Ausweichen auf vermeintlich schonendere, frei verkaufliche, aber oftmals ungeprufte Praparate fuhren kann. Es wurde der Frage nachgegangen, welche Praparate in welcher Indikation und in welcher Phase der Schwangerschaft und Stillzeit sichere therapeutische Optionen darstellen. Anhand einer Literaturrecherche in MEDLINE, Fachbuchern und -zeitschriften, einer Stichwortsuche in der Suchmaschine Google, sowie einer Sichtung der Onlineplattformen entsprechender Forschungs- und Beratungsstellen wurden die aktuellen Empfehlungen zur Pharmakotherapie bei Schwangeren und Stillenden herausgearbeitet. Es besteht eine solide Datenbasis fur eine effiziente und sichere Pharmakotherapie in der Schwangerschaft und Stillzeit im MKG-chirurgischen Bereich. Alle in der Praxis bewahrten und gewohnten Substanzen konnen (mit Ausnahme von nichtsteroidalen Antirheumatika im 3. Trimenon) eingesetzt werden. Leitsubstanzen sind bei der Lokalanasthesie Articain und Lidocain, bei den Analgetika Paracetamol, bei den Antibiotika Penicilline, Cephalosporine und Makrolide und bei den Mundspulungen Chlorhexidin und Hexetidin. Die zur Entscheidung der Substanzwahl notwendigen Informationen sind jederzeit online oder als App verfugbar. Somit gibt es keinen Grund, einer Schwangeren oder Stillenden eine medizinisch notwendige Pharmakotherapie vorzuenthalten. Die Nichtgabe eines der empfohlenen Medikamente kann durch den schmerz- und/oder infektbedingten Stress ein hoheres Risiko fur das Kind darstellen als dessen Gabe.

Der von Nietzsche ausgerufene Tod Gottes zeitigt im Werk Carl Einsteins mehrere Reaktionen. In den Dilettanten des Wunders und in G.F.R.G. uberwiegt die Skepsis hinsichtlich eines Ersatzmythos, den er gleichzeitig mit Nachdruck fordert. Der Begriff der Gemeinschaft spielt dabei eine zentrale Rolle, erst in kommunistischer, dann anarchistisch-syndikalistischer Gestalt. Unter dem Einfluss der Negerplastik sucht Einstein aber auch eine asthetische Losung des transzendentalen Problems, die um 1930 in der direkten Forderung nach einem neuen Mythos gipfelt. Wahrend er die fremdkulturelle Primitive „ethnologisiert“, glaubt Einstein nun uber surrealistische Verfahren das kollektive Unbewusste erreichen zu konnen. 1933 wird diese Hoffnung durch einen anderen Mythos, den des Dritten Reiches, zerschmettert – „jude ohne gott“, erwacht Einstein aus seinen utopischen Traumen im Exil: In der Fabrikation der Fiktionen wendet er nunmehr seine „Ethnologie du Blanc“ zur radikalen Ideologiekritik, in die er sich selber mit einschliest. Ideell und auch wirtschaftlich ruiniert, engagiert er sich in Spanien im antifaschistischen Kampf und erlebt wiederum Gemeinschaft auf Seiten des legendaren Buonaventura Durutti.

The Roll-Out Solar Array (ROSA) flight experiment was launched to the International Space Station (ISS) on June 3rd, 2017. ROSA is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors. This paper discusses the effort to model the structural dynamics of ROSA using finite element modeling. Two distinct and agnostic approaches were used by separate teams to assess the structural dynamics of the solar array prior to ground vibrational testing and flight testing. Results from each approach are compared to measured dynamics from accelerometers and photogrammetry data gathered on orbit. Advantages and disadvantages of each approach are discussed as are preliminary efforts to calibrate the models to the empirical data for the benefit of future modeling efforts on similar space structures.

The Roll-Out Solar Array (ROSA) flight experiment was launched to the International Space Station (ISS) on June 3rd, 2017. ROSA is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors. This paper will discuss the results of various structural dynamics experiments conducted on the ISS during the weeks following launch. Data gathered from instrumentation on the solar array wing during the experiments was previously compared with pre-flight predictions from two different Finite Element Modeling (FEM) efforts. In this paper, data generated from photogrammetry is compared with accelerometer data and used to extend previous conclusions. Whereas previous analyses were only able to track the accelerations of six discrete points on the structure and photovoltaic (PV) blanket of ROSA, the photogrammetry analysis makes available displacements for dozens of points distributed throughout the array. This larger data set makes it possible to compare higher-order PV blanket modes with FEM predictions, in addition to verifying conclusions reached using accelerometer data. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays.

This paper presents a static analysis of three-dimensional sandwich beam structures. Several higher-order, displacements-based theories as well as classical Euler–Bernoulli’s and Timoshenko’s models are derived by approximating the displacement field over the cross-section in a compact, unified form. The governing differential equations and the boundary conditions are derived in a nuclear form which is representative of a generic term in the displacement field approximation. This approach yields a problem formulation that does not depend upon the kinematic approximation order. The resulting boundary value problem is analytically solved by a Navier-type solution. The analysis is carried out in terms of displacement and stress field due to bending and torsional loads in slender and short sandwich beams. The effect of the skin/core anisotropy ratio is investigated. Results are assessed towards reference three-dimensional finite element solutions showing that the sandwich problems can be accurately yet efficiently solved.

The Roll-Out Solar Array (ROSA) flight experiment was launched to the International Space Station (ISS) on June 3rd, 2017. ROSA is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors. This paper will discuss the results of various structural dynamics experiments conducted on the ISS during the weeks following launch. Data gathered from instrumentation on the solar array wing during the experiments are compared with pre-flight predictions from two different finite element modeling efforts. Two distinct methods were used to reconstruct the modal characteristics of ROSA from the data collected on orbit. Of particular interest in this effort are the first few system modes and mode shapes of the array, the amount of structural damping present, and degree of structural thermal interaction seen during eclipse exit. Discrepancies between the behavior predicted by the models and that observed on orbit are identified and discussed. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays.

GANGNAM STYLE ist ein ironisches Kunstmärchen, das von dem Wunsch des armen Helden (alias Psy) seinen Anfang nimmt, das sagenhafte ›Gangnam‹ (konkret: ein superreicher Stadtteil von Seoul) zu erobern. Da der Märchen-held kein Pferd besitzt, erfindet er einen Pferde- bzw. Reitertanz, er wird ge-wissermaßen zum ›Kentaur‹. Dennoch sind seine Errungenschaften blamabel. Selbst in dem von ihm erfundenen Tanz wird er von einem authentischen Gangnam-Jüngling übertrumpft, der mehr noch als ein Pferd einen Merce-des-SLK mit 184 Pferdestärken sein eigen nennt. Der ›Hans im Unglück‹ findet jedoch sein ›Königreich‹ in Gestalt einer U-Bahn-Prinzessin. Seine Traumfrau, deren Tugenden er von Anfang an propagiert, entspricht freilich einem auch in (Süd-) Korea recht konventionellen Rollenbild, dem er selber verpflichtet ist: Tagsüber wird anständig gearbeitet, zur Nacht hin erfolgt ein ›switching‹ des Verhaltenscodes zur ausgelassenen Sinnesfreude hin. Der Held gibt sich mit dieser erotischen Erfüllung zufrieden, ohne je ganz nach ›Gangnam‹ ge-langt zu sein, also z.B. eine Millionärstochter als Braut erworben zu haben. »Oppan Gangnam Style« fungiert eingangs als imperativer Impuls des Hel-den, zugleich als das leitende Prinzip des gesellschaftlichen Erfolgs, quasi als mythischer ›Big Brother‹, von dem der Held schließlich zu profitieren sucht, indem er gegenüber der umworbenen jungen Frau selber in die Rolle des ›Oppan‹, des kompetenten ›älteren Bruders‹ schlüpft., GANGNAM STYLE is an ironic arts-fairy story originating from the desire of a needy hero (alias Psy) to conquer the famous ›Gangnam‹ (an extremely afflu-ent district in Seoul). Since the hero of the fairy story cannot afford a horse as opposed to the rich Gangnam people, he creates a horse-, or rather a horse rider-dance and thereby turns into a ›centaur‹. Despite this, his achievements are mediocre. He is even beaten at the execution of the dance he developed by a young, authentic Gangnam citizen who owns more than one horse in the shape of a Mercedes SLK with 184 ›horse‹ power. However, ›Unlucky Hans‹ finds his ›Empire‹ in the guise of a ›Subway Princess‹. His dream lady, whose virtues he propagates from the very beginning, corresponds to an everyday, common girl even by (South-)Korean standards and is in accordance with his own commitments: thorough work during the day and a ›switching‹ at night of the code of behavior to hedonism. The hero is satisfied with this romantic accomplishment without himself having become a genuine ›Gangnam‹ insid-er, that is for example, by securing as a bride the daughter of a millionaire. »Oppan Gangnam Style« initially functions as an imperative impulse of the hero. At the same time it is the leading principle of success in that society, in other words the mythical ›Big Brother‹, whom the hero tries to take advantage of by himself transforming into the role of ›Oppan‹, the competent ›older (big) brother‹, in order to court the young lady.

The decomposition of propargyl iodide, C 3 H 3 I → C 3 H 3 + I, and the following combination of propargyl radical, C 3 H 3 + C 3 H 3 → C 6 H 6, have been observed in the incident shock in mixtures of 1%, 2%, and 5% C 3 H 3 I in Kr, over 800–2000 K, for nominal post-shock pressures of 20 and 130 Torr. The iodide dissociates readily, the endothermic reaction producing an easily resolved positive density gradient whose kinetic modeling allows extraction of precise rates showing strong falloff. A simple Gorin-model RRKM treatment of the measurements results in a k ∞ = 3.35 × 10 18 T −0.9 exp (−22192/ T ) s −1 . The initial positive gradient is immediately followed by a strong negative, showing exothermic reaction from propargyl combination. Modeling of this gradient with an assumed theoretical product distribution, provided by J.A. Miller, results in propargyl combination rates in excellent agreement with current theory and having a strong negative temperature dependence, the rate dropping near a factor of forty over 800–2000 K. Possible errors associated with the need to assume a product distribution are discussed and it is suggested that this should not result in rate uncertainties for the C 3 H 3 combination reaction greater than ±50%.

The dissociation of 1, 2 and 4% 1,4-dioxane dilute in krypton was studied in a shock tube using laser schlieren densitometry, LS, for 1550-2100 K with 56 ± 4 and 123 ± 3 Torr. Products were identified by time-of-flight mass spectrometry, TOF-MS. 1,4-dioxane was found to initially dissociate via C-O bond fission followed by nearly equal contributions from pathways involving 2,6 H-atom transfers to either the O or C atom at the scission site. The 'linear' species thus formed (ethylene glycol vinyl ether and 2-ethoxyacetaldehyde) then dissociate by central fission at rates too fast to resolve. The radicals produced in this fission break down further to generate H, CH(3) and OH, driving a chain decomposition and subsequent exothermic recombination. High-level ab initio calculations were used to develop a potential energy surface for the dissociation. These results were incorporated into an 83 reaction mechanism used to simulate the LS profiles with excellent agreement. Simulations of the TOF-MS experiments were also performed with good agreement for consumption of 1,4-dioxane. Rate coefficients for the overall initial dissociation yielded k(123Torr) = (1.58 ± 0.50) × 10(59) × T(-13.63) × exp(-43970/T) s(-1) and k(58Torr) = (3.16 ± 1.10) × 10(79) × T(-19.13) × exp(-51326/T) s(-1) for 1600T2100 K.

A combination of experiment and theory is applied to the self-reaction kinetics of phenyl radicals. The dissociation of phenyl iodide is observed with both time-of-flight mass spectrometry, TOF-MS, and laser schlieren, LS, diagnostics coupled to a diaphragmless shock tube for temperatures ranging from 1276 to 1853 K. The LS experiments were performed at pressures of 22 +/- 2, 54 +/- 7, and 122 +/- 6 Torr, and the TOF-MS experiments were performed at pressures in the range 500-700 Torr. These observations are sensitive to both the dissociation of phenyl iodide and to the subsequent self-reaction of the phenyl radicals. The experimental observations indicate that both these reactions are more complicated than previously assumed. The phenyl iodide dissociation yields approximately 6% C(6)H(4) + HI in addition to the major and commonly assumed C(6)H(5) + I channel. The self-reaction of phenyl radicals does not proceed solely by recombination, but also through disproportionation to benzene + o-/m-/p-benzynes, with comparable rate coefficients for both. The various channels in the self-reaction of phenyl radicals are studied with ab initio transition state theory based master equation calculations. These calculations elucidate the complex nature of the C(6)H(5) self-reaction and are consistent with the experimental observations. The theoretical predictions are used as a guide in the development of a model for the phenyl iodide pyrolysis that accurately reproduces the observed laser schlieren profiles over the full range of the observations.

The three-body dissociation of 1,3,5-triazine (s-triazine, s-C3H3N3 3HCN) has been observed in incident shock waves with the laser-schlieren technique. The experiments use 5% triazine/Kr and cover 1630–2350 K for 100–600 Torr. These experiments show dissociation rates with strong falloff and a slight but fully expected pressure dependence. The dissociation is without secondary reaction save for a possible, but rather unlikely, contribution from the isomerization HCN HNC. Electronic structure calculations of the transition-state properties (G3B3, HL1, Eo = 84.6 kcal/mol) are used to construct a Rice–Ramsperger–Kassel–Marcus (RRKM) model whose fit to the rate measurements suggests a 〈ΔE〉down of 1200 cm−1. However, a seemingly better fit is achieved using the barrier of 81 kcal/mol proposed by Dyakov et al. (J. Phys. Chem. A 2007, 111, 9591–9599). With this barrier k∞ (s−1) = 5.3 × 1016 exp(−86.6(kcal/mol)/RT), and the fit now accepts the more routine 〈ΔE〉down = 126(T/298)0.9. It seems the dissociation most likely occurs by a direct, one-step, “triple” dissociation to 3HCN, although the present experiments cannot rule out a multistep process. Vibrational relaxation of the triazine was also examined in 5% and 20% mixtures with Kr over 770–1500 K for pressures between 6 and 14 Torr. Relaxation is very fast, with a slight inverse temperature dependence, Pτ rising from 100 to 200 ns-atm over the full temperature range. Integrated gradients are in good accord with calculated total changes in density, indicating a single exponential relaxation. A separate investigation of relaxation in the related molecule pyrazine (500–1300 K, in 1% and 5% in Kr, between 13 and 66 Torr) is included. Again relaxation is rapid, but here the temperature dependence seems more normal, the relaxation times decreasing slightly with temperature. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 211–220, 2010

Bankfull stage and flow are considered important thresholds in geomorphology. Bankfull indicators were collected at 17 gaged and 28 ungaged relatively undisturbed peninsular Florida streams, ranging in drainage area from 0.52 to 805 km2 (0.2 to 311 square miles) with valley slopes from 0.02 to 2.27 percent. Based on prevalence among sites, comparisons of indicator slopes with water slopes, and correspondence of hydrologic data with morphologic data, the elevation of the flat floodplain was determined to be the most reliable bankfull indicator at sites with a wetland floodplain, while the elevation of the inflection on the bank was the most reliable indicator at sites with an upland floodplain. Small streams and rivers in peninsular Florida achieve bankfull stage relatively frequently compared to the modal values elsewhere, with flow durations of about 25 percent. Results have implications to river restoration projects, and regional differences in relations between hydrology and channel dimensions. Abstract: La etapa en la que el cauce esta lleno y su flujo se consideran importantes en los umbrales de la geomorfologia. Indicadores de tal etapa se recolectaron en los 17 calibrados y 28 no calibrados cauces peninsulares relativamente poc alterados de la Florida, fluctuando en area de drenaje de 0.52 a 805 km2 (0.2 a 311 millas cuadradas) con una pendiente en el valle de 0.02 a 2.27 por ciento. Basado en la prevalencia entre las localidades, las comparaciones de los indicadores de inclinacion con vertientes de agua, y correspondencia de datos hidrologicos con datos morfologicos, la elevacion del llano de inundacion fue determinada para ser el indicador mas confiable de la etapa de cauce lleno en lugares con humedales en los llanos de inundacion, mientras que la elevacion de la inflexion en el banco fue el indicador mas fiable en lugares con llanos de inundacion en tierras altas. Los rios y riachuelos de la peninsula de la Florida alcanzaron la etapa de cauce lleno con relativa frecuencia en comparacion con los valores modales en otros lugares, con duraciones de flujo de alrededor de 25 por ciento. Los resultados tienen implicaciones para proyectos de restauracion de rios, y diferencias regionales en relaciones entre la hidrologia y las dimensiones del canal.

The decomposition of cyclohexane (c-C(6)H(12)) was studied in a shock tube using the laser-schlieren technique over the temperature range 1300-2000 K and for 25-200 Torr in mixtures of 2%, 4%, 10%, and 20% cyclohexane in Kr. Vibrational relaxation of the cyclohexane was also examined in 10 experiments covering 1100-1600 K for pressures below 20 Torr, and relaxation was found to be too fast to allow resolution of incubation times. The dissociation of 1-hexene (1- C(6)H(12)), apparently the sole initial product of cyclohexane decomposition, was also studied over 1220-1700 K for 50 and 200 Torr using 2% and 3% 1-hexene in Kr. On heating, cyclohexane simply isomerizes to 1-hexene, and this then dissociates almost entirely by a more rapid C-C scission to allyl and n-propyl radicals. This two-step reaction results in an initial small density gradient from the slight endothermicity of the isomerization. The gradient then rises strongly as the product 1-hexene dissociates. For the lower temperatures, this behavior is fully resolved here. For the higher pressures, 1-hexene decomposition generates negative gradients (exothermic reaction) as the radicals formed begin to recombine. Cyclohexane also generates such gradients, but these are now much smaller because the radical pool is depleted by abstraction from the reactant. A complete mechanism for the 1-hexene decomposition and for that of cyclohexane involving 79 reactions and 30 species is used in the final modeling of the gradients. Rate constants and RRKM fit parameters for the initial reactions are provided for the entire range of conditions. The possibility of direct reaction to allyl and n-propyl radicals, without stabilization of the intermediate 1-hexene, is examined down to pressures as low as 25 Torr, without a clear resolution of the issue. High-pressure limit rate constants from RRKM extrapolation are k(infinity)(c-C(6)H(12) --1-C(6)H(12)) = (8.76 x 10(17)) exp((-91.94 kcal/mol)/RT) s(-1) (T = 1300-2000 K) and k(infinity)(1-C(6)H(12) --(*)C(3)H(7) + (*)C(3)H(5)) = (1.46 x 10(16)) exp((-69.12 kcal/mol)/RT) s(-1) (T = 1200-1700 K). This high-pressure rate for cyclohexane is entirely consistent with the notion that the isomerization involves initial C-C fission to a diradical. These extrapolated high-pressure rates are in good agreement with much of the literature.

The dissociation of diacetyl dilute in krypton has been studied in a shock tube using laser schlieren densitometry at 1200-1800 K and reaction pressures of 55 +/- 2, 120 +/- 3, and 225 +/- 5 Torr. The experimentally determined rate coefficients show falloff and an ab initio/Master Equation/VRC-TST analysis was used to determine pressure-dependent rate coefficient expressions that are in good agreement with the experimental data. From the theoretical calculations k(infinity)(T) = 5.029 x 10(19) (T/298 K)(-3.40) exp(-37665/T) s(-1) for 300T2000 K. The laser schlieren profiles were simulated using a model for methyl recombination with appropriate additions for diacetyl. From the simulations rate coefficients were determined for CH(3) + CH(3) = C(2)H(6) and CH(3) + C(4)H(6)O(2) = CH(3)CO + CH(2)CO + CH(4) (k(T) = 2.818T(4.00) exp(-5737/T) cm(3) mol(-1) s(-1)). Excellent agreement is found between the simulations and experimental profiles, and Troe type parameters have been calculated for the dissociation of diacetyl and the recombination of methyl radicals.

The dissociation of acetone: CH 3 C OCH 3 → CH 3 C O + CH 3 , quickly followed by CH 3 CO → CH 3 + CO, has been examined with Laser-Schlieren measurements in incident shock waves over 32–717 Torr and 1429–1936 K using 5% acetone dilute in krypton. A few very low pressure experiments (∼10 Torr) were used in a marginal effort to resolve the extremely fast vibrational relaxation of this molecule. This effort was partly motivated as a test for molecular, “roaming methyl” reactions, and also as a source of methyl radicals to test the application of a recent high-temperature mechanism for ethane decomposition [J.H. Kiefer, S. Santhanam, N.K. Srinivasan, R.S. Tranter, S.J. Klippenstein, M.A. Oehlschlaeger, Proc. Combust. Inst. 30 (2005) 1129–1135] on the reverse methyl combination. The gradient profiles show strong initial positive gradients and following negative values fully consistent with methyl radical formation and its following recombination. Thus C–C fission is certainly a large part of the process and molecular channels cannot be responsible for more than 30% of the dissociation. Rates obtained for the C–C fission show strong falloff well fit by variable reaction coordinate transition state theory when combined with a master equation. The calculated barrier is 82.8 kcal/mol, the fitted 〈Δ E 〉 down = 400 (T/298) cm −1 , similar to what was found in a recent study of C–C fission in acetaldehyde, and the extrapolated k ∞ = 10 25.86 T −2.72 exp(−87.7 (kcal/mol)/ RT ), which agrees with the literature rate for CH 3 + CH 3 CO. Large negative (exothermic) gradients appearing late from methyl combination are accurately fit in both time of onset and magnitude by the earlier ethane dissociation mechanism. The measured dissociation rates are in close accord with one earlier shock-tube study [K. Sato, Y. Hidaka, Combust. Flame 122 (2000) 291–311], but show much less falloff than the high pressure experiments of Ernst et al. [J. Ernst, K. Spindler, H.Gg. Wagner, Ber. Bunsenges. Phys. Chem. 80 (1976) 645–650].

Recent years have seen rapid advances in ultrasound techniques, increasing the chances of early diagnosis of changes in the female breast, irrespective of the presence of signs or symptoms. Sonography is excellent for the observation of breast tissue changes. However in common with other medical imaging techniques, it does not provide qualitative data--it is only a diagnostic guide. The article, therefore, includes a list of criteria which are useful in differential diagnosis of benign and malignant tissue changes.

The dissociation and relaxation of CO 2 has been reexamined in the incident shock wave with the laser-schlieren technique. These new experiments covered 1377-6478 K, and 42-750 Torr, and improvements partly described herein have permitted accurate determination of both rate and incubation time. In general the steady rate measurements are in agreement with other recent determinations. The one anomaly is that the new rates are not fully second order; they vary about 50% over 70-600 Torr. This unexpected feature is actually quite consistent with the recent literature, which shows a similar trend. However, attempts to produce this result with RRKM calculations were unsuccessful. Relaxation times are in agreement with available literature, and incubation time to relaxation time ratios lie between 1.5 and 3 over 4000-6600 K, consistent with findings for other molecules. These ratios are much smaller than those recently derived from reflected-shock experiments by Oehlschlaeger et al. (Z. Phys. Chem. 2005, 219, 555). A simple argument suggests such large values are indeed anomalous, although why they are too large is not clear.

The classic pyrolytic decomposition of acetaldehyde has been examined to the higher temperatures used in combustion and also lower pressures with 85 laser-schlieren, shock-tube measurements of density gradient covering 40–500 torr and 1550–2400 K. This work is supplemented and modeled with a CASPT2 based variable reaction coordinate RRKM prediction of the dissociation kinetics. These RRKM predictions are then incorporated in good two-dimensional master equation fits of the strong falloff seen in the laser-schlieren experiments, and also that shown in some previous shock-tube results using UV absorption of the acetaldehyde as diagnostic. The laser-schlieren data provide not only unambiguous dissociation rates but also solid indications of the secondary chemistry. Modeling of the full density gradient profiles offers good estimates of rates for H-atom abstraction from both the acetaldehyde and the HCO radical, again at high temperatures.

The thermal dissociation of ethane has been examined in two complementary sets of shock-tube experiments that together cover 1400–2200 K and a pressure range of 70–5700 torr. These experiments used both laser-schlieren and UV absorption of CH3 as diagnostics. In addition, that ethane exhibits a double vibrational relaxation has been confirmed for high temperatures, demonstrating slow IVR in this molecule, and both relaxation times have been determined for 1000–1500 K. Some estimates of dissociation incubation times were possible over about 1900–2100 K. An RRKM model calculation using the earlier Klippenstein–Harding theoretical model provides a remarkably accurate description of the complete range of data with 〈ΔE〉down = 120 (T/300)0.9 cm−1. Over 1400–2200 K, the k∞ from this model is 8.03 × 1028 T−3.52 exp (−95346 cal/mol/RT) s−1. It is suggested that the success of this model shows that there is no non-RRKM behavior in this reaction.

We report a shock-tube, laser-schlieren investigation of the molecular dissociation of the title trifluoroethane, CF 3 CH 3 → CH 2 CF 2 + HF, over very high temperatures, 1600-2400 K, and a wide range of sub-atmospheric pressures, 15-550 Torr. The density gradients are well fit by a simple two-reaction mechanism and accurate dissociation rates obtained. The results are compared with a k ∞ calculated from a G3 TS for this molecular elimination, which is a superb fit to the available lower-T data and a reliable extrapolation of k ∞ to high temperatures. The derived rate constants show a very deep falloff from this extrapolation but surprisingly little variation with pressure. This peculiarity is so severe that RRKM calculations dramatically fail to account for the behavior. The dissociation seems to be a clear example of an intrinsic non-RRKM process (nonstatistical dissociation). This conclusion is strongly supported by the observation of double vibrational relaxation at both dissociating and nondissociating temperatures, an unambiguous demonstration of slow IVR. Using a simple model with division into two groups of states, the deep falloff is found to be consistent with a rate-controlling slow IVR, not with low collision efficiency. The model suggests an IVR rate of ∼10 8 s - 1 for dissociation energies.

This article reports the results of investigations into the process of cell death induced in the Chinese hamster ovary cell K1 subclone (CHO K1) by okadaic acid (OA), a hydrophobic polyether produced by marine dinoflagellates. The IC50 was about 13 nM OA after 24 h of treatment, as determined using neutral red. With the MTT assay, the IC50 was 25 nM, although in this case 25% of the initial staining was still observed at 100 nM. Hoechst staining showed that mitotic figures accumulated at 12 nM OA after a 24- or 48-h treatment. In experiments limited to a 3-day treatment without changing the medium, CHO K1 cells were engaged in the death process at 50 nM OA after about 20 h and at 10 nM OA after 48 h. In many cells nuclear fragmentation that resulted in the apparent appearance of vesicles correlated with increasing cellular volume. But additional cell fragmentation was not observed with any treatment, and the chromatin material seemed to progressively disappear inside the cells. DNA fragmentation was analyzed by electrophoresis and with the TUNEL technique. With both techniques, the DNA was fragmented by 48 h in both 25 and 50 nM OA. Electrophoresis showed that both adherent and nonadherent cells were affected. Annexin-positive/ propidium iodide (PI)–negative cells were rarely observed after OA treatment. Some were seen under the scanning cytometer after 20 h at 50 nM OA or after 48 h at 10 nM OA, but they were never detected by flow cytometry. Most of the time scanning cytometry showed either unstained cells or PI-positive (annexin-positive or -negative) cells (48 h, 50 nM, or 72 h, 10 nM). Flow cytometry cytograms showed two cell subpopulations: one composed of a majority of smaller cells, the other of larger cells. The larger cells markedly decreased with time and OA treatment (50 and 100 nM). Stained-cell counting showed that all cells that stained were both annexin- and PI positive and that most PI-positive cells were smaller. Ki67 antigen labeling showed the proliferative activity of CHO K1 cultures but also demonstrated the loss of this activity in smaller cells treated with 50 nM OA for 48 h. We concluded that in our culture conditions the main OA target within CHO K1 cultures was dividing cells. Our results suggest that cells with disturbed metaphase–anaphase enter apoptosis, leading to necrotic daughter cells. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 383–394, 2003

Dissociation, vibrational relaxation, and unimolecular incubation have all been observed in shock waves in isobutene with the laser-schlieren technique. Experiments covered a wide range of high-temperature conditions: 900–2300 K, and post-incident shock pressures from 7 to 400 torr in 2, 5, and 10% mixtures with krypton. The surprising observation is that of vibrational relaxation, well resolved over the full temperature range. The resolved process is completely exponential, with relaxation times in the range 20–120 ns atm. Relaxation and dissociation are clearly separated for T > 1850 K, with estimated incubation times near 200 ns atm. Incubation is essential for modeling of the very low-pressure decomposition. Modeling of gradients with a chain mechanism initiated by CH fission produces an excellent fit and accurate dissociation rates that show severe falloff. A restricted-rotor, Gorin-model RRKM analysis fits these rates quite well with the known bond-energy as barrier and 〈ΔE〉down = 680 cm−1. The extrapolated k∞ is log k∞(s−1) = 19.187–0.865 log T −87.337 (kcal/mol)/RT, in good agreement with previous work. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 381–390, 2003

Objective: To investigate whether a bronchial blocker (BB) placed through a routinely used single-lumen tube (SLT) to achieve 1-lung ventilation is appropriate in patients undergoing a minimally invasive direct coronary artery bypass (MIDCAB) operation. Design: Clinical trial. Setting: University hospital. Participants: Patients scheduled for elective MIDCAB operation (n = 159). Interventions: Group A was treated with a left-sided double-lumen tube (DLT) and served as the control group. Group B was intubated with a routinely used SLT in combination with a BB. Measurements and Main Results: The following data were collected: (1) time required for placement of each tube, (2) ventilation pressures, (3) lung compliance, (4) dislocations of the DLT or BB, (5) effectiveness of lung collapse, and (6) PaO2 and fraction of inspired oxygen. In 4 patients (4%) of group B, the BB could not be placed within an acceptable time so that 155 patients (50 patients in group A, 105 patients in group B) were statistically analyzed. Statistically significant differences during 1-lung ventilation were found for peak and mean inspiratory pressure (p 0.05) and PaO2 and fraction of inspired oxygen (p > 0.05). Lung collapse was insufficient in 1 patient of group A (2%) and in 2 patients of group B (2%). Conclusion: To achieve 1-lung ventilation during a MIDCAB procedure, the use of a BB combined with an SLT is an appropriate technique as an alternative to the commonly used DLT. Copyright 2002, Elsevier Science (USA). All rights reserved.

We model recent experiments on the vibrational relaxation of oxirane in a shock tube. A master equation is developed which includes self-collisions of the oxirane, leading to a nonlinear master equation. This master equation is also applied to a more limited study of vibrational relaxation for cyclopropane in a shock tube. The time variation of the temperature dependence of the bath is also included in the calculations. Good agreement between the modeling and experiments are obtained through a fit to the energy transfer parameters. These fits demonstrate that self-collisions are dominant in promoting the relaxation even for mixtures of Kr and oxirane where the oxirane is 2% and 4% dilute. This dominance comes from two sources: (1) much larger energy transfer per collision for oxirane-oxirane collisions and (2) resonant energy transfer effects. For cyclopropane, some of the good fits show smaller energy transfer characteristics for self-collisions than buffer gas collisions. Even in these cases self-collisions are an important part of the energy transfer process through resonant energy transfer effects.