bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas phase kinetic study of the thermal reactions of t‐butoxy radicals with germane, phosphine, and trimethylsilane
Authors: Lee Yong‐Eun , Choo Kwang Yul 
Published: January 2005

AbstractThe hydrogen abstraction reactions of tert‐butoxyl with germane, phosphine, and trimethylsilane were studied by pyrolyzing di‐t‐butyl peroxide in the temperature range of 403 to 458 K. From the reported rate constant for the tert‐butoxy radical decomposition in the literature, the absolute rate constants were determined from the study of competitive reaction between t‐butoxy radical decomposition

and hydrogen abstraction reaction. (t‐BuO + RH → t‐BuOH + R, where RH = GeH4, PH3, and HSiMe3)The Arrhenius parameters are found to be as follows:

Ea(kcal mol−1)
Log A(1.mol−1s−1)

t‐BuO + SiHMe3
2.1
8.5

t‐BuO + GeH4
1.9
9.1

t‐BuO + PH3
1.4
9.0
Effects of olefins on the thermal decomposition of propane part V. Effect of butene‐2‐Cis
Authors: Dombi A. , Huhn P. 
Published: January 2005

AbstractThe thermal decomposition of butene‐2‐cis at low conversion and its effect on the pyrolysis of propane have been studied in the temperature range 779‐812 K.It was established that 2‐butene decomposes in a long‐chain process, with the chain cycle

(Besides the radical path, the molecular reaction
equation image
can also play a role in the formation of the products.)The thermal decomposition of propane is considerably inhibited by 2‐butene, which can be explained by the fact that the less reactive radicals formed in the reactions between the olefin and the chain‐carrying radicals regenerate the chain cycle more slowly than the original radicals in the above chain cycle or in the reactions

The reactions of the 2‐propyl radical

are further initiation steps. The ratios of the rate coefficients of the elementary steps of the decomposition (Table III) have been determined via the ratios of the products.Estimation of the radical concentrations indicated that only the methyl, 2‐propyl and methylallyl radicals are of importance in the chain termination.On the basis of the inhibition‐influenced curves, the role of the bimolecular initiation steps.

could be clarified in the presence of 2‐butene.
Rate constants and kinetic isotope effects for hydrogen/deuterium abstraction by chlorine atoms from the chloromethyl group in CH2ClCH2Cl, CD2ClCD2Cl, CH2ClCHCl2, and CH2ClCDCl2
Authors: Tschuikow‐Roux E. , Faraji F. , Niedzielski Jan 
Published: January 2005

AbstractThe abstraction of hydrogen and deuterium from 1,2‐dichloroethane, 1,1,2‐trichloroethane, and two of their deuterated analogs by photochemically generated ground state chlorine atoms has been investigatedin the temperature range 0–95°C using methane as a competitor. Rate constants and their temperature coefficients are reported for the following reactions
equation image
Over the temperature range of this investigation an Arrhenius law temperature dependence was observed in all cases. Based on the adopted rate coefficient for the chlorination of methane [L.F. Keyser, J. Chem. Phys., 69, 214 (1978)]

which is commensurate with the present temperature range, the following rate constant values (cm3 s−1) are obtained:

The observed pure primary, and mixed primary plus α‐ and β3‐secondary kinetic isotope effects at 298 K are k3/k6 = 2.73 ± 0.08, and k1/k2 = 4.26 ± 0.12, respectively. Both show a normal temperature dependence decreasing to k3/k6 = 2.39 ± 0.06 and k1/k2 = 3.56 ± 0.09 at 370 K. Contrary to some simple theoretical expectations, the kinetic isotope effect for H/D abstraction decreases with increasing number of chlorine substituents in the geminal group in a parallel manner to the trend established previously for C1‐substitution in the adjacent group. The occurrence of a β‐secondary isotope effect, k4/k5, is established; this effect suggests a slight inverse temperature dependence.
Gas phase kinetic and thermochemical data for endo‐ and exo‐5‐monosubstituted bicyclo[2.2.2]Oct‐2‐Enes
Authors: Van Mele B. , Boon G. , Huybrechts G. 
Published: January 2005

AbstractThe thermal reactions of endo‐ and exo‐5‐Y bicyclo[2.2.2]oct‐2‐enes (NYBO and XYBO) where Y = methyl, ethyl, and isopropyl have been studied in the gas phase between 567 and 695 K. For both isomers they are parallel first‐order retro‐Diels‐Alder reactions with elimination of ethene (E) and monosubstituted ethene (YE).The observed Arrhenius parameters are used to discuss the mechanism and to estimate the heats of formation and the entropies of NYBO and XYBO. Group values are proposed for estimation of these thermochemical data for compounds of the same type by means of the methods of Benson.
Estimations of OH radical rate constants from H‐atom abstraction from CH and OH bonds over the temperature range 250‐1000 K
Authors: Atkinson Roger 
Published: January 2005

AbstractRate constants for overall H‐atom abstraction by hydroxyl radicals from CH and OH bonds are estimated for alkanes, haloalkanes, aldehydes, ketones, ethers, alcohols, nitriles, and nitrates over thetemperature range 250–1000 K. These estimated rate constants utilize the modified Arrhenius expression K = A'T2e−E'/T in combination with the recommendations given in the recent review and evaluation of OH radical kinetics of Atkinson [1]. This estimation procedure gives good agreement, generally to within better than a factor of 2, of the estimated rate constants with theserecommendations.
High temperature kinetics of the thermal decomposition of the lower alkanoic acids
Authors: Doolan K. R. , Mackie J. C. , Reid C. R. 
Published: January 2005

AbstractThe thermal decomposition of propanoic acid dilute in argon has beenstudied in a single‐pulse shock tube over the temperature range of 1100‐1500 K and over the pressure range of 14‐18 atm. The decomposition kinetics have been satisfactorily computer modelled by means of afree radical mechanism involving H and OH chains.Recent single‐pulse shock tube product analyses of acetic acid decomposition have been computer modelled using a free radical mechanism for decarboxylation coupled to a unimolecular dehydration reaction.A comparison between the thermal decomposition kinetics of the C1C3 alkanoic acids is made. The present studies do notprovide evidence for the participation of transition states involving a pentavalent carbon atom in the pyrolyses of the lower alkanoic acids.
The photooxidation of allyl chloride
Authors: Edney Edward O. , Shepson Paul B. , Kleindienst Tadeusz E. , Corse Eric W. 
Published: January 2005

AbstractThe photooxidation of allyl chloride was studied by irradiation either in 100‐L Teflon bags or in a 22.7‐m3 Teflon smog chamber in the presence of added NOx. In the absence of added hydrocarbons, the reaction involves a Cl atom chain, which leads to a highly reactive system. A reaction mechanism is presented to account for the following photooxidation products: chloroacetaldehyde, formaldehyde, 1,3‐dichloroacetone, 3‐chloroacrolein, acrolein, glyoxal, chloroperoxyacetyl nitrate, and peroxypropenyl nitrate. The rate constant for OH reaction with allyl chloride at 298 K was measured by a relative rate method under conditions where the Cl atom chain length was small and was found to be kOH = 1.7 × 10−11 cm3 molecule−1 s−1. The rate constant for O3 reaction with allylchloride at 298 K was found to be kO3 = 1.5 × 10−18 cm3 molecule−1 s−1.
Reaction of the NO3 radical with CO: Determination of an upper limit for the rate constant using FTIR spectroscopy
Authors: Hjorth J. , Ottobrini G. , Restelli G. 
Published: January 2005

AbstractAn upper limit for the reaction rate of CO with the nitrate radical NO3 has been determined equal to 4 × 10−19 cm+3 molec−1 s−1 at 295 ± 2 K. In the experiment the isotopic species C13O16 and C13O18 mixed at 1–2 ppmv level in synthetic air have been reacted with NO3 and the reaction followed using long path infrared absorption FT spectroscopy. The result is of interest in the studies on the role played by NO3 in nighttime tropospheric chemistry.
Kinetics and mechanism of the OH + CIO2reaction
Authors: Poulet G. , Zagogianni H. , Bras G. Le 
Published: January 2005

AbstractThe rate constant k1 for the reaction of OH radicals with CIO2 molecules was measured in a discharge flow system over the temperature range 293 ≤ T ≤ 473 K and at low pressures, 0.5 ≤ P ≤ 1.4 torr, using electron paramagnetic resonance or laser‐induced fluorescence to monitor the pseudo first‐order decay of OH concentrations. At 293 K, the value obtained for k1 was (7.2 ± 0.5) × 10−12 cm3 molecule−1 s−1. Within the temperature range of this study, a negative temperature dependence was observed: k1 = (4.50 ± 0.75) × 10−13 exp[(804 ± 114)/T] cm3 molecule−1 s−1. HOCl was detected by mass spectrometry as a product of the reaction and was titrated using OH + Cl2 as a source in the calibration experiments. A simulation of the mechanism of the OH + ClO2 reaction indicated that HOCl was mainly produced in the first reaction step. Both this result and the observed T dependence of k1 suggest that this reaction proceeds via an intermediate adduct with a cyclic geometry.
Time‐resolved vibrational chemiluminescence: Rate constants for the reactions of F atoms with H2O and HCN, and for the relaxation of HF (v = 1) by H2O and HCN
Authors: Frost Robert J. , Green David S. , Osborn Martin K. , Smith Ian W. M. 
Published: January 2005

AbstractRate constants have been determined at (298 ± 4) K for the reactions:
equation image
and the relaxation processes:
equation image
Time‐resolved HF(1,0) emission was observed following the photolysis of F2 with pulses from an excimer laser operating on XeCl (λ = 308 nm). Analysis of the emission traces gave first‐order constants for reaction and relaxation, and their dependence on [H2O] and [HCN] yielded:
The kinetics and the mechanism of the thermal gas‐phase reaction between NO2 and 1,1‐dichlorodifluoroethylene, CF2CCl2
Authors: Czarnowski J. , Schumacher H. J. 
Published: January 2005

AbstractThe kinetics of the gas phase reaction between NO2 and CF2CCl2 has been investigated in the temperature range from 50 to 80°C. The reaction is homogeneous. Three products are formed: O2NCF2CCl2NO2 and equimolecular amounts of CINO and of O2NCF2C(O)Cl. The rate of consumption of the reactants is independent of the total pressure, the reaction products, and added inert gases and can be represented by a second‐order reaction:

However, the distribution of the products is influenced by the pressure of the present gases, which favor the formation of the dinitro‐compound in a specific way. The effect of CF2CCl2 is the greatest. In the absence of added gases, the ratio of O2NCF2CCl2NO2 to that of O2NCF2C(O)Cl is proportional to (CF2CCl2 + γP products).The experimental results can be explaned by the following mechanism:
equation image
P and X represent the products and the added gases:
Temperature‐Induced Unfolding of Ribonuclease A Embedded in Spherical Polyelectrolyte Brushes
Authors: Wittemann Alexander , Ballauff Matthias 
Published: January 2005

AbstractSummary: We use Fourier Transform infrared spectroscopy (FT‐IR) spectroscopy to study the thermal unfolding and refolding behavior of ribonuclease (RNase A) adsorbed to spherical polyelectrolyte brushes (SPB). The SPB consist of a solid poly(styrene) core of ca. 100 nm diameter onto which long chains of poly(styrene sulfonic acid), PSS have been densely attached. The particles bearing the adsorbed protein are dispersed in aqueous buffer solution at a pH close to the isoelectric point (9.6) of the protein. The secondary structure of the protein was analyzed by FT‐IR spectroscopy and compared to the structure of the native protein before adsorption. The unfolding of the free RNase A in solution was found to be fully reversible with an unfolding temperature of 65 °C, in accordance to previous studies. However, after adsorption to the SPB, the unfolding temperature of the protein molecule is lowered by 10 °C and the Van't Hoff enthalpy of the unfolding process is significantly reduced. Moreover the unfolding of the adsorbed protein is irreversible. The phenomenon may be explained by an increase in binding sites due to unfolding of the globular structure.Protein adsorption to a spherical polyelectrolyte brush.imageProtein adsorption to a spherical polyelectrolyte brush.
Studies on the Synthesis of 2,3‐O‐Hydroxyalkyl Ethers of Cellulose
Authors: Schaller Jens , Heinze Thomas 
Published: January 2005

AbstractSummary: Novel 2,3‐O‐hydroxyethyl‐ and 2,3‐O‐hydroxypropyl cellulose products were synthesized by heterogeneous etherification of 6‐O‐(4‐monomethoxytrityl) cellulose (MMTC). Due to the very hydrophobic character of MMTC, the reaction was successful in the presence of anionic and non‐ionic detergent in the reaction mixture yielding the 2,3‐O‐cellulose ethers with a molar degree of substitution (MS) varying between 0.25 and 2.00 after detritylation. The products were characterized by means of 1H and 13C NMR spectroscopy including two‐dimensional methods. The 2,3‐O‐hydroxypropyl cellulose samples are soluble in water at a MS as low as 0.8. The spectroscopic studies showed that the unusual solubility results from a preferred substitution of hydroxy groups of the anhydroglucose unit while the newly formed hydroxy moieties are included in the reaction to a minor extent only. In contrast, conventionally synthesized hydroxypropyl cellulose is soluble in water starting at a MS of about 4.0 because of the formation of oxyethylene side chains.13C DEPT 135 NMR spectrum of 2,3‐O‐hydroxypropyl cellulose.image13C DEPT 135 NMR spectrum of 2,3‐O‐hydroxypropyl cellulose.
Evolving anticancer drug valproic acid: Insights into the mechanism and clinical studies
Authors: Blaheta Roman A. , Michaelis Martin , Driever Pablo Hernáiz , Cinatl Jindrich 
Published: January 2005

AbstractThe short chain fatty acid valproic acid (VPA) and VPA‐analogs modulate the biology of diverse tumor cell entities by inducing differentiation, inhibiting proliferation, increasing apoptosis, and immunogenicity and by decreasing metastatic and angiogenetic potential. This review updates an earlier one in 2002, reflecting the interest in VPA as a potent anticancer drug. A number of in vitro studies show that the types of known tumor cells susceptible to VPA is steadily increasing. Of special note is the strong antineoplastic activity of VPA in chemoresistant cancer cells. A novel and promising approach is combining VPA with other drugs to achieve a broad therapeutic index. Clinical studies are underway and the preliminary results indicate that VPA alone or in combination offers a promising avenue of treatment, both in solid and hematopoetic malignancies. © 2005 Wiley Periodicals, Inc.
Bronchiolitis obliterans in children
Authors: Kurland Geoffrey , Michelson Peter 
Published: January 2005

AbstractBronchiolitis obliterans (BO) in children is a relatively rare diagnosis. The increase in lung and bone marrow transplantation in children, however, has led to a heightened interest in BO, as this is one of the important complications of those procedures. This article will discuss BO as an entity that can follow any of several illnesses or toxic exposures, in addition to following allogeneic lung or bone marrow transplantation. The complex and incompletely understood pathology, pathogenesis, and molecular pathology involved in BO remain the subject of ongoing investigations. As the prognosis for BO is uncertain and treatment is often unsuccessful, the continued need for the recognition of surrogate markers for BO in patients at risk and the development of better forms of therapy are paramount. This review will describe our current understanding of BO, and will call attention to those research areas that require continuing efforts in order to prevent or treat this entity. Pediatr Pulmonol. 2005; 39:193–208. © 2005 Wiley‐Liss, Inc.
Therapeutic efficacy of milrinone in the management of enterovirus 71‐induced pulmonary edema
Authors: Wang Shih‐Min , Lei Huan‐Yao , Huang Mei‐Chih , Wu Jing‐Min , Chen Chun‐Ta , Wang Jieh‐Neng , Wang Jen‐Ren , Liu Ching‐Chuan 
Published: January 2005

AbstractHand, foot, and mouth disease and herpangina are the major clinical manifestations of enterovirus 71 (EV71) infections. Brain‐stem encephalitis and pulmonary edema are severe complications that can lead to death. This study was designed to evaluate the potential therapeutic effect of milrinone, a phosphodiesterase (PDE) inhibitor, in the treatment of patients with EV71‐induced pulmonary edema. We conducted a historically controlled trial of 24 children with severe EV71‐induced pulmonary edema from April 1998–June 2003 in southern Taiwan. Patients were divided into groups treated before and after the introduction of milrinone therapy. Etiological diagnosis was established by viral cultures and confirmed by specific immunofluorescence and neutralization tests. All 24 patients were below 5 years of age. The mortality was lower in the milrinone‐treated vs. nontreated group (36.4% vs. 92.3%, P = 0.005). Sympathetic tachycardia was decreased in patients treated with milrinone compared to controls (144 ± 17/min vs. 206 ± 26/min, P = 0.004). A marked decrease in IL‐13 (77 ± 9 pg/ml vs. 162 ± 88 pg/ml, P = 0.001) was observed in milrinone‐treated patients compared to controls. There was a significant reduction in white blood cell (10,838 ± 4,537/mm3 vs. 19,475 ± 7,798/mm3, P = 0.009) and platelet (257 ± 45 × 103/mm3 vs. 400 ± 87 × 103/mm3, P = 0.001) counts in milrinone‐treated patients compared to controls. These results were associated with improvement in sympathetic regulation and decrease in IL‐13 production. Milrinone therapy may provide a useful therapeutic approach for this highly lethal disorder. Pediatr Pulmonol. 2005; 39:219–223. © 2005 Wiley‐Liss, Inc.
Die Ursachen der Bildsamkeit der Tone
Authors: Salmang Hermann 
Published: January 2005

AbstractZur Erzeugung einer bildsamen Masse aus einem festen und einem flüssigen Körper (z. B. aus Ton und Wasser) bedarf es
geeigneter morphologischer Eigenschaften des festen Körpers (geringe Korngröße, Blättchenform, Rauhheit, Spaltbarkeit und geringer Härte).
der Erzeugung einer viscosen Schicht zwischen den Teilchen, was durch eine chemische Oberflächenreaktion zwischen dem festen und dem flüssigen Körper bewirkt wird. Kolloide können die Bildsamkeit etwas erhöhen. Alle diese Anforderungen an bildsame Massen sind beim System Ton–Wasser am besten erfüllt
.
Die Oberflächenspannung geschmolzener Metalle und Legierungen. II. Die Oberflächenspannung von Zinn, Blei, Antimon, Kupfer, Zinn‐Wismut, Blei‐Wismut, Kupfer‐Antimon, Kupfer‐Zinnlegierungen und Gußeisen
Authors: Drath G. , Sauerwald F. 
Published: January 2005

AbstractDie Methode der Messung des Maximalen Blasendruckes zur Bestimmung der Oberflächenspannung der Metalle wurde weiterhin bis zur Verwendbarkeit bei 1200° ausgebildet. Es wurden gemessen die Oberflächenspannungen von Sn, Pb, Sb, Cu und von BiSn‐, BiPb‐, VuSb‐, CuSn‐Legierungen und es wurden einige vorläufige Werte für Roheisen bestimmt.
Zähigkeit und Gallertbildung von Cerihydroxyd‐Sol
Authors: Chakravarti D. N. , Ghosh S. , Dhar N. R. 
Published: January 2005

Abstract1. Man erhält feste, durchsichtige Gallerten, wenn man zu einem Sol von Cerihydroxyd — hergestellt durch Dialyse einer Lösung von Ceriammoniumnitrat in der Kälte — Elektrolyte zusetzt. Die Gallertbildung findet nicht statt bei dem Sol desselben Stoffes, das in der Hitze hergestellt ist.
Die quantitative Bestimmung des Tantals auf röntgenspektroskopischem Wege
Authors: v. Hevesy G. , Böhm J. 
Published: January 2005

AbstractZur quantitativen röntgenspektroskopischen Bestimmung des Tantals setzt man der Analysenprobe so lange Erbium zu, bis die TaL‐α1‐ und die ErLβ2‐Linie gleich stark erscheint. Durch Division der verwendeten Erbiumoxydmenge durch 4,7 erhält man den unbekannten Tantaloxydgehalt der Analysenprobe. Die Benützung von Linien mit ganz geringem Wellenlängenunterschied (im obigen Falle 7,6 X‐Einheiten), erlaubt die Eliminierung zahlreicher Fehlerquellen.
Über „aktives”︁ Eisen
Authors: Simon A. , Kötschau K. 
Published: January 2005

AbstractDie Versuche dienten zur Beantwortung folgender Fragen: Wird Ferrum reductum durch Verreiben „aktiv”︁? Worauf beruht die Aktivität? Wer ist Träger der aktiven Eigenschaften? Was geht beim Altern vor sich? Welchen Einfluß üben ultraviolette Strahlen hinsichtlich Alterung aus? Zu dem Zweck werden zuerst die die Aktivität anzeigenden Reaktionen studiert.
Die Molekularvolumina einfacher und komplexer Halogenide des Platins
Authors: Klement R. 
Published: January 2005

AbstractBei der Bildung der komplexen Halogenosalze des Platins aus den einfachen Komponenten erleiden die Volumina der Halogene keine wesentlichen Veränderungen, wohl aber beim Übergang von den koordinativ ungesättigten Verbindungen des 2‐wertigen Platins zu den koordinativ gesättigten des 4‐wertigen Platins, und zwar in diesem Falle erhebliche Kontraktion.
Über die Kristallstruktur des Hexamminkobaltijodids
Authors: Meisel Karl , Tiedje Walter 
Published: January 2005

AbstractDie Untersuchung der Kristallstruktur des Co(NH3)6J3 ergab folgendes:

Der Elementarkörper ist kubisch und hat die Kantenlänge 10,9 Å. Er ist flächenzentriert und enthält 4 chemische Molekeln.
Der Kristallbau erfolgt nach Raumgruppe Oh5 bzw. O3. Die Atomlagen sind:

equation image

Die Entfernung Co—J beträgt 1,9 Å.
Zur Wertbestimmung von Adsorbentien
Authors: Bachmann Wilhelm , Maier Ludwig 
Published: January 2005

Abstract1. Es wird gezeigt, daß zur Beurteilung der Wirksamkeit von Adsorbentien, speziell von Kieselsäuregelen, gegenüber Dämpfen die zumeist übliche Bestimmung des sogenannten Sorptionsmaximums als nicht ausreichend angesehen werden muß, sondern daß vielmehr die Aufnahme einer vollständigen Sorptions‐ und Desorptionskurve erforderlich ist, wenn man über die Eignung der einzelnen Adsorbentien, beispielsweise zu bestimmten technischen Zwecken, ein vollgültiges Urteil gewinnen will.
Beiträge zur Kenntnis der seltenen Erden
Authors: Wilke‐Dörfurt Ernst , Schliephake Otto 
Published: January 2005

Abstract1. Es wird gezeigt, daß die Perchlorate der seltenen Erden wegen ihrer großen Löslichkeit und der Eigenschaften des ClO4‐Anions sich gelegentlich gut fur Erdtrennungen eignen.
Über die Geschwindigkeit von Reaktionen zwischen zwei flüssigen Phasen
Authors: Fraenkel W. , Wengel E. , Cahn L. 
Published: January 2005

AbstractDie Hauptergebnisse der vorliegenden Untersuchungen sind : 1. Für alle untersuchten Amalgame (A1, Zn, Be, Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs) wurde ein einheitlicher Typus der Zersetzungsreaktion festgestellt.
Über die Lösung von Metallen in Salzchmelzen
Authors: Eitel Wilhelm , Lange Bruno 
Published: January 2005

AbstractVorstehende Arbeit beschäftigt sich mit der Frage nach der Natur des Lösungsvorganges von Metallen in Salzschmelzen bei hohen Temperaturen.1. Daß die Auflösung der Metalle nicht kolloidal erfolgt, läßt sich ultramikroskopisch und durch Untersuchung des Tyndallichtes zeigen.
Wichtige Faktoren bei der Untersuchung der Adsorption aus Lösungen
Authors: Sen K. C. 
Published: January 2005

Abstract1. Es wurde gezeigt, daß bei Ermittlung der Adsorption der Wert des an I Gramm Adsorbens adsorbierten Stoffes beeinflußt werden kann durch die Menge des verwendeten Adsorbens, durch die Anfangskonzentration und durch das Gesamtvolumen der Lösung, in der der Versuch ausgeführt wird. Dies trifft besonders zu bei den sogenannten chemischen Adsorptionen, wo eine große chemische Affinität zwischen Adsorbens und adsorbiertem Stoff besteht.
Plastizität IV. Plastische Massen mit Siliciumdioxyd
Authors: Ruff Otto , Hirsch Bruno 
Published: January 2005

AbstractEs wird gezeigt, daß sich Quarzpulver durch Mahlen mit reinem Wasser, und noch leichter in Gegenwart von Säuren zu plastischen Massen verarbeiten läßt, die nach dem Gießverfahren der Keramik geformt und bis 1500° gebrannt werden können. Die Massen enthalten einen gewissen Prozentsatz an Quarzgel bzw. Quarzsol.