bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Papier‐Chromatographie auf dem Fettgebiet, LI. Mitteilung: Präparative Trennung von Triglyceriden mit Hilfe der Papier‐Chromatographie
Authors: Kaufmann H. P. , Wessels H. , Viswanathan C. V.
Published: November 2006

Es wird ein Verfahren zur pc‐Trennung größerer Mengen von Triglyceriden beschrieben. Die Trennung erfolgt nach dem Prinzip der Mehrfach‐Entwicklung auf Rundfiltern oder in aufsteigender Arbeitsweise in den Systemen Paraffin/Eisessig, Paraffin/Aceton‐Acetonitril und Paraffin/Aceton‐Methanol. Auf dem Chromatogramm lassen sich bis zu 40 mg trennen. Die gleichzeitige Entwicklung mehrerer Chromatogramme zwischen 2 Glasplatten gestattet es, die Menge noch weiter zu steigern. Die mit Hilfe der Methodik zur Verfügung stehenden relativ großen Substanzmengen erleichtern die weitere Analyse der in den einzelnen Fraktionen auftretenden kritischen Partner.
Die Qualitätsbeurteilung von Futterfett
Authors: Niesar K.‐H.
Published: November 2006

Die allgemeinen Anforderungen an die Fettsäure‐Zusammensetzung von Futterfetten werden diskutiert und entsprechende Schlüsse für ihre Eignung als Energieträger in bestimmten Fütterungsrationen gezogen. Über Verträglichkeitsstudien verdorbener Fette in der Geflügelmast wird berichtet und auf die Problematik der chemischen Analytik von bereits in Mischfuttern eingebrachten Futterfetten eingegangen.
Zusammenhänge zwischen Gebrauchswert der Wäsche und Inkrustierung
Authors: Stache H.
Published: November 2006

Die speziell für Leibwäsche unter dem Sammelbegriff Tragegefühl zusammengefaßten Faktoren, wie Griff, Saugvermögen, Schweißtransport, Luftdurchlässigkeit und Wiedertrocknungsvermögen, wurden im Zusammenhang mit der Inkrustierung an Test‐Personen untersucht.
Verhalten von Hautoberflächenfett gegenüber Textilien sowie Wasch‐ und Lagerungseinflüssen
Authors: Oldenroth O.
Published: November 2006

Unterhemden aus den Faserstoffen Baumwolle, Polyamid, Polyester bzw. Polyacrylnitril wurden von mehreren Versuchspersonen jeweils 8 Tage getragen. Die mögliche Auswaschbarkeit des in die Textilien gelangten Hautfettes wurde bie Waschtemperaturen von 30°, 60° und 90°C erprobt. Nach 5 Trageperioden ist die in den Unterhemden verbliebene Restfettmenge ermittelt worden. Weiterhin wird über den Einfluß des Hautoberflächenfettes auf die Vergilbungserscheinungen durch Trage‐, Belichtungs‐ und Lagerungseinflüsse berichtet.
11‐, 12‐ und 13‐Ketofettsäuren
Authors: Breusch F. L. , Kirkali A.
Published: November 2006

Die großenteils unbekannten 11‐, 12‐ und 13‐Ketofettsäuren bis C22 wurden synthetisiert. In zwei Diagrammen werden die Schmelzpunktswerte der bis jetzt bekannten isomeren Reihen von Ketofettsäuren getrennt nach geradzahligen und ungeradzahligen C‐Ketten dargestellt und diskutiert.
Kennzeichnung von Wachsen durch Differential‐Thermo‐Analyse
Authors: Lange J. , Jochinke H.
Published: November 2006

Zur Untersuchung der Erstarrungs‐ und Schmelzvorgänge bei Wachsen wurde das bekannte Verfahren der Differential‐Thermo‐Analyse eingesetzt. Es hat sich gezeigt, daß mit Hilfe der Differential‐Thermo‐Analyse natürliche und synthetische Wachse sowie Paraffine und andere wachsähnliche Produkte gut gekennzeichnet werden können. In einfachen Fällen lassen sich auch Bestandteile von Wachsmischungen erkennen.
Zur Kenntnis der Lipoide der Kaffeebohne V: Die Lipoid‐Bestandteile des Kaffee‐Getränkes
Authors: Kaufmann H. P. , Schickel R.
Published: November 2006

Nach einer umfassenden Übersicht über die Inhaltsstoffe der Kaffeebohne und deren Verhalten bei der Röstung werden die Lipoid‐Bestandteile verschiedener Kaffee‐Aufgüsse und technisch behandelter Kaffeebohnen näher untersucht. Zur Ermittlung der innerhalb der einzelnen Lipoidklassen eingetretenen Veränderungen diente die präparative Auftrennung mit Hilfe der Dünnschicht‐Chromatographie.
Dünnschicht‐Chromatographie auf dem Fettgebiet, XVI. Mitteilung: Versuche zur zweidimensionalen quantitativen Analyse von Lipoiden auf photometrischem Wege
Authors: Kaufmann H. P. , Mukherjee K. D.
Published: November 2006

Methylester und Glyceride von Fettsäure‐Gemischen sowie Cholesterinester werden dünnschicht‐chromatographisch auf der AgNO3‐Kieselgel‐Schicht getrennt und die Chromatogramme mit Hilfe der zweidimensionalen Arbeitsweise nach Verkohlung auf der Platte photometrisch ausgewertet.
Pyridinderivate — eine neue Klasse von Oxydationshaarfarben
Authors: Lange F. W. , Boställe Husie
Published: November 2006

Der Chemismus der Oxydationshaarfarben zeigt, daß die auf dem Haar entstehenden Endprodukte nicht farbstabil sind. Es wurde erstmalig darüber berichtet, daß von über 100 untersuchten Derivaten des Pyridins insbesondere die Diaminopyridine und das 2,6‐Dihydroxypyridin zur Bildung von waschechten und pH‐stabilen Oxydationshaarfarben geeignet sind. Die Farbgebung von 8 verschiedenen, präparativ dargestellten Derivaten des 2,5‐Diaminopyridins wird beschrieben. Zur physiologischen Verträglichkeit und zur Strukturaufklärung der noch unbekannten farbigen Endprodukte werden Hinweise gegeben.
Abkömmlinge des Tricyclodecans auf dem Fettgebiet I: Tricyclodecamethanal als Ausgangsmaterial
Authors: Kaufmann E. H. H. P. , Grothues B.
Published: November 2006

Das durch Oxo‐Synthese technisch hergestellte Tricyclodecamethanal (TCDM) wurde durch Oxydation in die Tricyclodecylsäure und durch Reduktion in den Tricyclodecylalkohol übergeführt. Die bei der Umsetzung von TCDM mit 1 Mol Malonsäure gewonnene β‐TCD‐Acrylsäure bestand aus 2 Isomeren, die durch Hydrierung die entsprechenden β‐TCD‐Propionsäuren und durch oxydative Spaltung die isomeren TCD‐Säuren lieferten. Mit 2 Mol Malonsäure bildete sich die β‐TCD‐Glutarsäure. Die durch Cyanhydrin‐Synthese dargestellte TCD‐Glykolsäure ließ sich ebenfalls in zwei Isomere trennen.
Investigations of the Biosynthesis and Degradation of Unsaturated Fatty Acids in Higher Plants and Photosynthetic Bacteria
Authors: James A. T. , Harris R. V. , Hitchcock C. , Wood B. J. B. , Nichols B. W.
Published: November 2006

A comparison of the biosynthesis of unsaturated fatty acids in higher plants, Chlorella vulgaris and photosynthetic bacteria showed that only the first two systems require oxygen as a cofactor. Photosynthetic bacteria degrade added fatty acids to acetate and synthesize their unsaturated acids by the anaerobic route irrespective of the presence or absence of air. Leaves and Chlorella synthesize linoleic and linolenic acids from oleic acid by direct desaturation. Oleic acid is synthesized differently by the two systems. Leaves degrade added fatty acids by α‐oxidation photosynthetic bacteria by β‐oxidation.
Zur Standardisierung von Waschversuchen an der menschlichen Haut
Authors: Tronnier H.
Published: November 2006

Es wird über Waschuntersuchungen an der menschlichen Haut unter Verwendung eines ‚Standardschmutzes’︁ in Salben‐ und Stiftform berichtet. Unter Hinweis auf mögliche Fehlerquellen wird die genaue Einhaltung der Standardbedingungen gefordert, unter denen sowohl an der unbehandelten Haut (Prüfung von Waschmitteln) als auch an der vorbehandelten (z. B. Untersuchung von Hautschutzmitteln) vergleichbare Werte erhalten werden. Auf die Notwendigkeit von Kontrollen bei über längere Zeit laufenden Versuchsserien innerhalb jeder Gruppe wird an Beispielen hingewiesen.
Netzmittel in der Kosmetik
Authors: Bergwein K.
Published: November 2006

Nach Festlegung der Begriffe Netzfähigkeit und Oberflächenspannung wird die Kapillarmethode zur Berechnung der Oberflächenspannung beschrieben. Die anionaktiven Netzmittel, darunter die Seife, und deren Vor‐ und Nachteile gegenüber den Syndets, ferner die Eigenschaften der Türkischrotöle, Fettalkoholsulfate, der Igepone, Lamepone, kationaktiven Netzmittel, nichtionogenen Netzmittel und der Sulfobernsteinsäureester werden mitgeteilt.
Pro‐ und Antioxydantien auf dem Fettgebiet XV: Die Wirkung von Heilmitteln auf Polyenfettsäuren, 2. Mitteilung: Schlafmittel
Authors: Kaufmann E. H. H. P.
Published: November 2006

Im Zusammenhang mit der für die Synthese von Schlafmitteln wichtigen Arbeitshypothese, daß Antioxydantien auch „Ermüdungsstoffe”︁ sein können, wird die Einwirkung von Barbituraten, Phenothiazinen, zur Narkose benutzten Sexualhormonen (Steroid‐Narkose) und Morphin auf Polyenfettsäuren untersucht. Während Barbiturate in vitro im Warburg‐Apparat nur geringe Wirkungen zeigten, erwiesen sich die übrigen Heilmittel als Antioxydantien von teilweise kräftiger Wirkung.
Abkömmlinge des Tricyclodecans auf dem Fettgebiet II: Eigenschaften und Reaktionen von Derivaten des Tricyclo‐(5,2,1,02,6)‐decans
Authors: Kaufmann E. H. H. P. , Steffan G.
Published: November 2006

Das durch Hydroformylierung von Dicyclopentadien zu erhaltende Hydroxymethyltricyclo‐(5,2,1,02,6)‐decan erwies sich als ein Gemisch von 9 Isomeren, die beim Alkohol selbst wie bei verschiedenen Derivaten durch die unterschiedliche sterische Abschirmung der jeweiligen funktionellen Gruppe verschiedene Reaktivitäten zeigten, was bei manchen Reaktionen zu einer merklichen Selektion führte. Allgemein war die Reaktivität gegenüber der gewöhnlicher Alkylverbindungen stark herabgesetzt. Auf die strukturelle Eigenart des Tricyclodecan‐Gerüstes wird auch die Bildung eines bemerkenswerten Carbonsäure‐Natriumsalz‐Komplexes und das Verhalten des Bistricyclodecylmethyl‐dimethyl‐ammoniumjodids zurückgeführt. Die ungenügende Micellbildung einiger Derivate zeigte, daß der Alkohol als Waschmittelrohstoff nicht geeignet ist.
Chemical Investigation on Egyptian Fats and Oils, Part VI: Studies on the Chemical Constitution of Some Cruciferae Seed Oils
Authors: Gad A. M. , Fiad S. , Shoeb Z. E. , Hassan M. M.
Published: November 2006

Die chemische Charakteristik und die chemische Zusammensetzung von 6 ägyptischen Cruziferen‐Saatölen wurden untersucht. Die Bestimmung der Fettsäure‐Zusammensetzung wurde mit Hilfe der UV‐spektrophotometrischen und papier‐chromatographischen Analyse durchgeführt. Die letztgenannte Methode scheint sowohl für die Bestimmung der gesättigten als auch der ungesättigten Fettsäuren geeigneter.
Zur Konstitution des „Tetracyclosqualens”︁
Authors: Sandermann W. , Casten R.
Published: November 2006

Nach Schrifttumsangaben kann Squalen mit Ameisensäure und schwefelsäurehaltigem Eisessig cyclisiert werden, ferner durch Behandlung mit Bleicherde bzw. Bortrifluorid. Durch Gas‐Chromatographie des „Tetracyclosqualens”︁ wurde nachgewiesen, daß es sich bei dem Cyclisierungsprodukt nicht um eine einheitliche Verbindung handelt, sondern um ein Gemisch von etwa 10 Individuen. Durch Dehydrierung mit Schwefel wurde 1,2,3‐Trimethylbenzol und 1,2,5‐Trimethylnaphthalin erhalten, während die Dehydrierung mit einem industriellen Kupfer‐Aluminiumoxyd‐Katalysator zu einem Kohlenwasserstoff führte, der sehr wahrscheinlich mit dem auch aus Andrographolid erhaltenen 1,2,5,6‐Tetramethylnaphthalin identisch ist. Die Ozonisation des „Tetracyclosqualens”︁ gab Aceton. Da es sich bei den Cyclosqualenen um Gemische einer großen Zahl von Verbindungen handelt, ist die Deutung ihrer IR‐Spektren recht schwierig.
Emulgatoren in Nahrungsmitteln
Authors: Ludwig K.‐ G.
Published: November 2006

Der Vf. behandelt die Chemie der Nahrungsmittelzusätze sowie deren Wirkung auf die Chemie der Stärken, Fette und Proteine. Es werden weiterhin eine Methode zur Auswahl von Emulgatoren sowie eine Zusammenfassung des heutigen Wissensstandes bezüglich ihrer Anwendung in Backwaren, Mehlen (cake mixes), Molkereierzeugnissen einschließlich Eiskrem sowie in Speiseölen und Speisefetten und in Süßwaren besprochen. Obwohl diese Nahrungsmittelzusätze allgemein als Emulgatoren bezeichnet werden, rufen sie häufig auch andere erwünschte Effekte hervor, wie z. B. längere Lagerfähigkeit und Frische bei Brot, was nicht auf die Emulgierung, sondern auf die Verzögerung der Kristallisation der Amylopektinfraktion der Stärke zurückzuführen ist.
Pro‐ und Antioxydantien auf dem Fettgebiet XVII: Fette und Fettstoffwechsel der Winterschläfer, 1. Mitteilung: Der Siebenschläfer (Glis glis L.)
Authors: Kaufmann E. H. H. P. , Garloff H. , Yekundi K. G.
Published: November 2006

Nach einem kurzen Überblick über das Schrifttum des Winterschlafes werden die Lipoide des Siebenschläfers (Glis glis L.) untersucht. Die Frage, ob gelbe Lipochrome durch Autoxydation von Polyenfettsäuren infolge Verringerung biologischer Antioxydantien, besonders von Vitamin E, entstehen, ließ sich nicht einwandfrei klären. Das braune Gewebe der sogenannten „Schlafdrüse”︁ enthält in Fettlösungsmittel unlösliche, wahrscheinlich durch Umsetzung von Polyenen mit Eiweißstoffen oder Autoxydation von Lipoproteinen, die diese enthalten, gebildete Stoffe.
Über einige Lipoid‐Inhaltsstoffe aus den Früchten von Anethum graveolens (L.) und Coriandrum sativum (L.)
Authors: Kartnig Th.
Published: November 2006

Aus dem Lipoidanteil der Früchte von Anethum graveolens (L.) und Coriandrum sativum (L.) konnten durch Ätherextraktion und anschließende Fraktionierung über einer Aluminiumoxyd‐Säule folgende Substanzen isoliert werden: Fructus Anethi: Ein Wachs (Zusammensetzung: C16‐, C18‐, C22‐, C24‐, C26‐ und C28‐Säuren sowie C24‐, C26‐, C28‐, C30‐ und C32‐Alkohole), die Cumarine Bergapten und Umbelliprenin, eine nicht genau identifizierte Verbindung (Phytofluen?) sowie γ‐Sitosterin. Fructus Coriandri: Eine nicht genau identifizierte Verbindung (Phytofluen?), γ‐Sitosterin, Umbelliferon und Scopoletin.
Gas‐chromatographische Trennungen mit modifizierten, linearen Temperaturprogrammen
Authors: Schmidt G. , Beringer K.
Published: November 2006

Die modifizierte, lineare Temperaturprogrammierung eignet sich in hervorragender Weise für die gas‐chromatographische Trennung von Substanzgemischen mit weitem Siedebereich, da sie sich jedem Trennproblem anpassen läßt. Nach einigen grundsätzlichen Überlegungen zur TGC wird in der vorliegenden Arbeit die Aufstellung eines solchen Matrix‐Temperaturprogramms am Beispiel eines Gemisches von Fischölfettsäure‐Estern beschrieben. Das durch lineares Temperaturprogramm gewonnene Übersichtschromatogramm wird in Bandengruppen eingeteilt, für diese die jeweils optimale Trenntemperatur ermittelt (isotherm), und schließlich werden die isothermen Stufen durch lineares Aufheizen miteinander verbunden.
Studies in Interesterification — Part I Production of Edible Fats from Vegetable Oils by Directed Interesterification
Authors: Chakroabarty M. M. , Das S. , Talapatra K.
Published: November 2006

A modification of the Eckey's directed interesterification process of individual fats and their mixtures has been studied. The fat after directed interesterification with NaOMe catalyst (0.4% w/w) was first chilled at 15° C for variable lengths of time (30 mts. — 180 mts.) and then subjected to further reaction at ca. 23° C from 12 hrs. — 168 hrs. depending on the type of fat and products desired to produce fats of different melting ranges. It was established that the above pretreatments influenced the end products but a minimum content of ca. 20% saturated fatty acids over C16 was necessary to produce a fat of melting range 36°–38° C.
Die mikrobiologische Qualitätskontrolle der Margarine III: Mikrobiologische Anforderungen an Margarine – Kontrollen im Fabrikbetrieb
Authors: Mossel D. A. A. , Engel C.
Published: November 2006

Nach einleitenden Angaben über die mikrobiologischen Anforderungen an Margarine behandelt der Vf. die Aufgaben und den Bereich der allgemeinen mikrobiologischen Kontrolle in der Fabrik. Weiterhin werden mikrobiologische Untersuchungen der Margarine‐Rohstoffe, der Fabrikationsmuster, der Einrichtungen sowie der Luft besprochen. Abschließend wird auf die Bewertung der in Nahrungsmittelfabriken angewandten Desinfektionsmittel und die Untersuchung der Margarine auf verbotene Konservierungsmittel eingegangen.
Physical Properties of Triglycerides II: Dispersion
Authors: Gouw T. H. , Vlugter J. C.
Published: November 2006

The liquid state dispersions of a number of triglycerides at 20° C and at 40° C are presented. From these data we have calculated the Lorentz‐Lorenz and the Gladstone‐Dale molar dispersions. A previously derived general equation is used to compute a quantitative relation between the dispersion of a mixture of triglycerides and its refractive index, density, and iodine value.
Epoxy Acids and Epoxidized Oils I: Quantitative Evaluation of Naturally Occurring Epoxy Fatty Acids in Some Malvaceous seed Oils
Authors: Hassan Mallah M. M. El , Souka L. M. , Gad A. M.
Published: November 2006

Quantitative evaluation of the epoxy acid contents of three seed oils, namely, Malva parviflora, Hibiscus esculentus (v. Baladi) and Hibiscus esculentus (v. Romey) were made using gas liquid chromatography, hydrobromination and picric acid methods. The epoxy acid percentages determined in the three samples were: 8.2, 2.5 and 3.1 respectively by gas liquid chromatography; 8.9, 5.4 and 6.1 by hydrobromination and 9.5, 4.9 and 7.0 by picric acid method. Picric acid method was found to be most satisfactory and gave reproducible results.
Untersuchungen über die Entstehung von Kohlenwasserstoffen in UV‐bestrahlten Fettsäuren und Fettsäure‐Estern
Authors: Lück H. , Rahman Q. Nahar , Kohn R.
Published: November 2006

Die Untersuchung der flüchtigen Verbindungen des Unverseifbaren und der Wasserdampfdestillate UV‐bestrahlter, gesättigter Fettsäuren und Fettsäure‐Ester haben ergeben, daß sowohl bei der Bestrahlung unter Luftzutritt als auch im Vakuum u. a. ungesättigte Kohlenwasserstoffe entstehen. Mit hoher Wahrscheinlichkeit handelt es sich dabei vor allem um 1,2‐Alkene, deren Ketten um 2 C‐Atome kürzer als die der entsprechenden Fettsäuren sind. Die flüchtigen Verbindungen des Unverseifbaren UV‐bestrahlter Ölsäure bestehen vorwiegend aus Carbonyl‐Verbindungen.
Fabricating Super‐Hydrophobic Lotus‐Leaf‐Like Surfaces through Soft‐Lithographic Imprinting
Authors: Liu Bin , He Yaning , Fan Yin , Wang Xiaogong
Published: November 2006

Summary: A soft‐lithographic imprinting approach to fabricate super‐hydrophobic surfaces has been developed in this work. In this process, fresh lotus leaves were used as masters and PDMS stamps were prepared by replica molding against the lotus‐leaf surfaces. By using the stamps and an epoxy‐based azo polymer solution as “ink”, the mimicked lotus‐leaf surfaces made of the polymer were fabricated by pressing the featured faces of the stamps against “inked” substrates and drying under a proper condition after peeling off the stamps. The lotus‐leaf‐like surfaces show super‐hydrophobic characteristics with the water contact angle higher than 150° and contact angle hysteresis less than 3°.

SEM images of lotus‐leaf‐like papillary structures on the imprinted surface.

magnified image

SEM images of lotus‐leaf‐like papillary structures on the imprinted surface.
Cover Picture: Macromol. Rapid Commun. 21/2006
Authors: Kim Dong‐Wan , Lee Du‐Hee , Kim Byung‐Kook , Je Hae‐June , Park Jae‐Gwan
Published: November 2006

Cover: An electrodeposition process is used to be an effective means of nanocomposite assembly directly onto Cu electrodes. This approach enables the simultaneous formation of the hybrid nanocomposite containing BaTiO3 nanoparticles covered with PMMA and Al metallic inclusions. Stabilization of colloidal BaTiO3 suspensions by the adsorbed PMMA is achieved. The hybrid three phase nanocomposites were assembled on Cu electrodes by incorporating Al nitrate salt into the suspension. Further details can be found in the article by D.‐W. Kim,* D.‐H. Lee, B.‐K. Kim, H.‐J. Je, and J.‐G. Park on page 1821.
Porous biodegradable polyester blends of poly(L‐lactic acid) and poly(ε‐caprolactone): physical properties, morphology, and biodegradation
Authors: Tsuji Hideto , Horikawa Gen
Published: November 2006

Poly(L‐lactic acid) (PLLA), poly(ε‐caprolactone) (PCL), and their films without or blended with 50 wt% poly(ethylene glycol) (PEG) were prepared by solution casting. Porous films were obtained by water‐extraction of PEG from solution‐cast phase‐separated PLLA‐blend‐PCL‐blend‐PEG films. The effects of PLLA/PCL ratio on the morphology of the porous films and the effects of PLLA/PCL ratio and pores on the physical properties and biodegradability of the films were investigated. The pore size of the blend films decreased with increasing PLLA/PCL ratio. Polymer blending and pore formation gave biodegradable PLLA‐blend‐PCL materials with a wide variety of tensile properties with Young's modulus in the range of 0.07–1.4 GPa and elongation at break in the range 3–380%. Pore formation markedly increased the PLLA crystallinity of porous films, except for low PLLA/PCL ratio. Polymer blending as well as pore formation enhanced the enzymatic degradation of biodegradable polyester blends. Copyright © 2006 Society of Chemical Industry
Distribution of a chemical following its application at a point source in an irrigation system
Authors: Osgerby J. M.
Published: November 2006

The development of large complex irrigation systems presents problems of pest control which are likely to become increasingly difficult to solve by established application methods. By applying a chemical at one point in such a system use can be made of the flow of water through the system to effect the necessary distribution. This technique has been used most effectively with the molluscicide Frescon (N‐tritylmorpholine). However, the complexity of many irrigation systems precludes the optimisation of the necessary rate of addition of molluscicide by any simple method.

In this paper a mathematical model of an irrigation system is described which enables a detailed study of this type of application to be made with speed and economy. An analogue computer has been used to solve the equations subject to the operating conditions of the irrigation system.
Control of Aphis fabae on broad beans (Vicia faba) by the systemic action of gamma‐bhc, thionazin and aldicarb
Authors: Skrentny R. F. , Ellis Jennifer A.
Published: November 2006

The in‐row application of aldicarb granules at 2 lb active ingredient (a.i.)/acre (2·24 kg/ha) at sowing gave complete control of Aphis fabae Scop. on broad beans (Vicia faba L. cv. Seville) up to 7 days before harvest and resulted in a three‐fold increase in yield compared with a similar thionazin treatment. Bean plants grown from seeds which were soaked in a gamma‐BHC solution at 20 ppm for 24 h prior to planting were protected from this aphid for most of the growing season almost as effectively as with the thionazin treatment.

A thin‐layer chromatography method was developed for the determination in plants and soil of aldicarb and its two major toxic metabolites, the sulphoxide and sulphone. Gas‐liquid chromatography was used to monitor the declining levels of gamma‐BHC and thionazin, and simultaneous bioassays were made with Aphis fabae on excised leaf discs from the crop. Analysis of the bean seeds and pods at harvest 90 days after sowing indicated no detectable gamma‐BHC, less than 0·01 ppm of thionazin and approximately 0·09 ppm total residue of aldicarb sulphone and sulphoxide. Approximately 22% and 13% of the applied aldicarb, in the form of sulphone and sulphoxide but not the parent compound, remained in the top 6 in (152 mm) of soil at the end of 2 and 4 months respectively.

Toxicity studies with Aphis fabae, Acyrthosiphon pisum Harris, and Megoura viciae Buck showed an increasing sensitivity in that order to gamma‐BHC at 1 ppm in bean plants. Acute toxicity investigations with feeding Aphis fabae indicated an increasing sensitivity in the order of gamma‐BHC < aldicarb sulphone < aldicarb sulphoxide < thionazin < aldicarb. Despite the high acute toxicity of thionazin to Aphis fabae it gave low protection against aphids, possibly owing to its relatively short persistence in both plants and soil when compared with aldicarb.
Polarography of herbicides—A preliminary survey
Authors: Hance R. J.
Published: November 2006

The polarographic behaviour of 38 herbicides was studied in 5 supporting electrolytes using single sweep derivative polarography. The 16 compounds showing the greatest polarographic activity were investigated further in order to estimate their detection limits. It is suggested that polarography might provide a useful technique for the analysis of 12 of these materials.
β‐Oxidation of certain growth regulators by plant tissues
Authors: Garraway J. L.
Published: November 2006

The growth‐regulating activity and metabolism, in pea and wheat tissues, of y‐(chloro‐phenoxy)‐, y‐(2,4‐dichlorophenoxy)‐ and y‐(N, N‐diniethylthiocarbamoylthio)‐substituted butyric, β‐hydroxy‐butyric, crotonic and vinylacetic acids have been investigated. With the exception of y‐(2,4‐dichlorophenoxy) vinylacetic acid in pea tissue, members of the two phenoxy series were degraded to the corresponding phenoxyacetic acid. Although members of the 2,4‐dichlorophenoxy series were less easily metabolised, both series exhibited similar activity. Other than with the y‐phenoxyvinylacetic acids, there were no appreciable differences in metabolism or growth‐regulating activity between members within a series. No evidence for the metabolism of y‐(2,4‐dichlorophenoxy)vinylacetic acid in pea tissue was found and this acid was also less active in the pea tests. Members of the N, N‐dimethyl‐thiocarbamoylthio series of acids, however, were less regular in their metabolic and growth‐regulating patterns. The substituted crotonic acid was inactive and unstable whilst pea tissue was found to metabolise the substituted acetic acid to inactive N‐methylcarbamoylthioacetic acid. The results with all active acids fit the accepted theory of metabolism by β‐oxidation.
Determination of tricyclohexyltin hydroxide residues in apples and pears
Authors: Trombetti G. , Maini P.
Published: November 2006

Plictran (tricyclohexyltin hydroxide, Cy3SnOH) residues in Stark Delicious apples and Passacrassana pears were determined. Field applications were carried out 7, 16 and 28 days before harvest. The analyses were carried out by two procedures: selective determination of the various Sn forms and determination of total Sn. The final spectrophotometric determinations were made as inorganic Sn using dithiol reagent. Average data obtained for apples were from 0.26 to 0.32 ppm of Sn (0.84–1.00 ppm Cy3SnOH) and for pears from 0.12 to 0.30 ppm of Sn (040–0.99 ppm Cy3SnOH).

A residues half‐life of 5–6 weeks for the apples and of 2 weeks for the pears was found.
Movement of dieldrin through soils: II.—In sloping troughs and soil columns
Authors: Thompson A. R. , Edwards C. A. , Edwards M. J. , Beynon K. I.
Published: November 2006

A glass‐lined trough was divided into six compartments by vertical transverse partitions and filled with soil to a height of 5 cm above the top of each partition. The base of the box and the surface of the soil sloped forwards one end with a gradient of 1 in 3·7. Dieldrin was applied (22 kg active ingredient/ha) to the soil surface in the uppermost compartment and the movement of dieldrin into leachate and down the slope was followed for 17 weeks. During this time 19·5 cm of rain fell. Less than 0·02% of the dieldrin appeared in the leachate and 99% of this was collected during the first 9 weeks, mainly from the uppermost compartment. Very little dieldrin moved down the slope and it was not detected in the leachate from compartments other than the treated one during 9–17 weeks after treatment.

In other experiments, 3 cylinders were filled respectively with sandy loam, heavy clay loam and peat which were transferred from the field as intact cores. Three other cylinders were filled with soils of the same types but broken up. Approximately 2% of the dieldrin leached through one column but usually it was much less than 0·1%. The largest amounts of dieldrin were leached down columns of heavy clay loam, intermediate amounts down columns of peat, and least through sandy loam. Ten times as much dieldrin leached down the columns of intact soil as through those with broken soil.

The results indicate that the movement of dieldrin from treated soil into water systems by leaching is limited and is unlikely to be a major pathway for the contamination of water.
Penetration of malathion into locusts
Authors: Ahmed Hafiz , Gardiner B. G.
Published: November 2006

Topically applied dilute solutions of malathion in kerosene extract ‘bottoms’ are more toxic and rapid in action than concentrated ones. Dilute solutions spread farther, penetrate more rapidly and consequently their rate of activation into the more toxic malaoxon is higher. With a single dose of 2·5% malathion the rate of penetration and activation varies according to the loci of topical application, presumably reflecting differences in sclerotisation of the cuticle. There are also inherent differences in the susceptibility of various body regions associated perhaps with the differential vulnerability of some vital internal organ (e.g. the central nervous system).

Very rapid hydrolytic degradation of malathion occurs through its conversion into malaoxon; locusts survive the lethal action of malathion by way of such degradation only where activation into malaoxon takes place in areas away from the sensitive head region, or where the rate of activation is slow, or where the circulatory system delays its arrival at such sensitive sites.

The higher rate of activation observable in immature adults of Schistocerca gregaria compared with mature adults is, however, counterbalanced by a higher rate of hydrolysis in the former.
A new model membrane system for the investigation of penetrative properties of plant growth substances
Authors: Kennedy C. D.
Published: November 2006

A new model membrane system has been developed which simulates in many ways the behaviour of a plant cell membrane. It is very suitable for studying the penetration and associated effects of plant growth substances because of its large size (4.9±0.3 cm2), its ease of preparation and its reproducible properties. It consists of a Millipore filter disc impregnated with egg yolk lecithin, n‐octanol and n‐tetradecane.

The effect of a number of plant growth and allied compounds on membrane conductivity at 25±0.5°c has been assessed by the addition of various concentrations of these substances to the solutions (0.01 M‐NaCl) on each side of the membrane. Certain compounds present in the solutions (pH 3.0) in the concentration range 10−4 M to 10−3 M considerably reduced the membrane conductivity. This effect was seen to be related to the structure of the hydrophobic portion of the molecule.

The flux through the membrane at 25±0.5°c of various organic substances (2,4‐D, benzoic acid, benzyl alcohol, benzamide and benzaldehyde) was measured for membranes containing no lecithin and compared with the flux obtained in comparable experiments, with lecithin present in the membrane. The presence of lecithin increased the flux, and the percentage increase was used to assess in each case the part played by lecithin in transport. The flux of 2,4‐D was much greater at low pH values.

A possible interpretation of these phenomena is suggested.
Determination of dithiocarbamates in carbonate‐based formulations of maneb and zineb
Authors: Simpson B. W.
Published: November 2006

A method is described for the determination of dithiocarbamates in maneb and zineb formulations containing carbonates. Carbon disulphide evolved during acid hydrolysis is trapped in methanol and measured directly by absorption at Vmax 3140mm−1.
Changes in cross‐resistance patterns of houseflies selected with natural pyrethrins or resmethrin (5‐benzyl‐3‐furylmethyl (±)‐cis‐trans‐chrysanthemate)
Authors: Farnham A. W.
Published: November 2006

A pyrethrins‐resistant strain of houseflies, 213ab, previously selected with a 1:10 (by wt.) mixture of natural pyrethrins and piperonyl butoxide, was further selected either with natural pyrethrins alone (strain NPR) or with resmethrin (strain 104). After 50 generations the two populations differed in their resistance to the natural and synthetic esters. Both were resistant to all pyrethroids. Part of strain NPR was immune and very much more resistant than strain 104 to the natural pyrethrins and allethrin, but it was only 2–3 times more resistant than strain 104 against the new synthetic esters resmethrin (5‐benzyl‐3‐furylmethyl (±)‐cis‐trans‐chrysanthemate), bio‐resmethrin (5‐benzyl‐3‐furylmethyl (+)‐trans‐chrysanthemate), pyresmethrin (5‐benzyl‐3‐furylmethyl pyrethrate) and 5B2Me3FC (5‐benzyl‐2‐methyl‐3‐furylmethyl (±)‐cis‐trans‐chrysanthemate). Pretreatment of both strains with sesamex diminished but did not eliminate resistance. Synergism was greater in strain NPR, especially with natural pyrethrins and allethrin. Both strains had great resistance to DDT indicating that resistance to DDT and pyrethroids is linked.

Differences in resistance to different compounds suggest that at least three factors can confer resistance, one of which, pen, delays penetration and two others involve detoxication, one py a on the acid side of the ester linkage and the other, py b, on the alcohol side. Natural pyrethrins and resmethrin select for different groupings of these factors. Treatment with resmethrin does not select for py b presumably because this mechanism cannot attack the resmethrin molecule. Similarly when piperonyl butoxide is added to the natural pyrethrins py b is inhibited and so removed from selection pressure. Under these conditions, the strain produced contains the same factors as one selected by resmethrin and so shows the same small resistance to natural pyrethrins alone.
Methyl benzimidazol‐2‐ylcarbamate, the fungitoxic principle of thiophanate‐methyl
Authors: Vonk J. W. , Sijpesteijn A. Kaars
Published: November 2006

A correlation was found between the formation of benzimidazol‐2‐ylcarbamate esters from the thiophanate fungicides [thiophanate, thiophanate‐methyl and 2‐(3‐methoxycarbonylthioureido)aniline] and the fungitoxie activity of these fungicides. Fungitoxic activity of the thiophanates is increased by ageing in aqueous media while fungitoxicity as well as conversion rate decrease at lower pH. It is concluded that it is not the thiophanates themselves but the corresponding benzimidazol‐2‐ylcarbamate esters that are responsible for the fungitoxic effect. Hence thiophanate‐methyl, like benomyl, is a precursor of the fungitoxic agent methyl benzimidazol‐2‐ylcarbamate (MBC). Indications were obtained that fungal metabolic activity can increase the rate of conversion of thiophanate‐methyl into MBC.
Metabolism of 3‐chloro‐4‐methoxyaniline and some N‐acyl derivatives in soil
Authors: Briggs G. G. , Ogilvie S. Y.
Published: November 2006

3‐Chloro‐4‐methoxyaniline at concentrations of 10ppm or more in soil is converted to a mixture of 3,3′dichloro‐4,4′‐dimethoxyazobenzene, 3‐chlorobenzoquinone‐4‐(3‐chloro‐4‐methoxy)anil and its reduction product 2,3′‐dichloro‐4‐hydroxy‐4‐'methoxydiphenylamine, probably by a free radical mechanism.

The herbicide metoxuron, N'‐(3‐chloro‐4‐methoxyphenyl)‐N,N‐dimethylurea and its demethylated metabolites probably break down to the amine too slowly in soil for coupling products to be detected. 3‐Chloro‐4‐methoxyacetanilide at 25 ppm rapidly gives rise to amine coupling products in soil slurries and ethyl N‐(3‐chloro‐4‐methoxyphenyl)carbamate does so after two months in the slurries.
The importance of whole plant studies in determining the biochemical mode of action of herbicides, as shown by studies with the experimental compound 6‐chloro‐2‐trifluoromethyl‐imidazo(4, 5‐b)pyridine
Authors: Bond C. P. , Corbett J. R.
Published: November 2006

The experimental herbicides 6‐chloro‐2‐trifluoromethyl‐imidazo(4,5b)pyridine and 2‐t‐butyl‐6‐chloroimidazo(4,5‐b)pyridine inhibit the Hill reaction of isolated chloroplasts by 50% at 1.5 and 2.4 pm, respectively. The first compound also uncouples plant and animal oxidative phosphorylation at about 50 pm, whilst the second compound is not an uncoupler, Surprisingly, light does not affect the herbicidal action of either compound on whole plants, so it is unlikely that the herbicidal activity is due to inhibition of the Hill reaction. Since both compounds probably act by the same mechanism, uncoupling of oxidative phosphorylation cannot be the site of herbicidal action, which therefore remains unknown.

A study of the metabolism of 6‐chloro‐2‐trifluoromethyl‐imidazo(4,5‐b)pyridine shows the occurrence of hydroxylation of the pyridine ring in rat and maize and conversion to trifluoroacetic acid in the latter.
Degradation of phosphonates. breakdown of soman (O‐pinacolyl‐methylphosphonofluoridate in wheat plants
Authors: Hambrook Joy L. , Howells D. J. , Utley D.
Published: November 2006

The fate of pinacolyl methylphosphonofluoridate (Soman) in wheat has been studied. Using wheat grown in hydroponic culture and applying the compound Soman via the culture solution, it has been shown that Soman is rapidly hydrolysed in the plants and that the resulting pinacolyl hydrogen methylphosphonate is further degraded to methylphosphonic acid.
Fungicidal activity and chemical constitution. XVIII. The activity of 4‐(1‐cyclo‐, 1‐iso‐ and 1‐n‐propylalkyl)‐2, 6‐dinitrophenols against powdery mildews
Authors: Fieldgate Diana M. , James Carolyn S. , Byrde R. J. W. , Clifford D. R. , Woodcock D.
Published: November 2006

The synthesis of seven 4‐(1‐cyclopropylalkyl)‐ and eight 4‐(1‐isopropylalkyl)‐2, 6‐dinitrophenols is described. When tested, together with six 4‐(1‐n‐propylalkyl)‐2, 6‐dinitrophenols, several of these compounds showed high protectant activities against apple and cucumber powdery mildews. Their activities are discussed in relation to π values obtained from g.l.c. retention times, and to hydrogen bonding characteristics (both intra‐and inter‐) derived from infrared spectroscopic data.
Resistance to anticoagulants in rodents
Authors: Greaves J. H.
Published: November 2006

The present status of anticoagulant‐resistant populations of Rattus norvegicus and Mus musculus in Britain is elaborated and special reference is made to evidence of the practical consequences of resistance for rodent control. A short review is given of genetical and toxicological aspects of resistance and it is predicted that continued dependence upon the anticoagulant rodenticides will lead to the development of new resistance problems. The failure of schemes for the eradication or containment of resistant rat populations by local use of alternative rodenticides is discussed and an approach based more soundly upon the principles of ecological genetics is indicated. It seems in practice, however, that the continued spread of resistance to anticoagulants in Britain is now inevitable and that the development of improved alternative rodenticides will be necessary in order to avoid a decline in the standard of rodent control.
Pyrethrum dermatitis I. The allergenic properties of various extracts of pyrethrum flowers
Authors: Rickett F. E. , Tyszkiewicz K. , Brown N. C.
Published: November 2006

Extracts of pyrethrum flowers were obtained by treatment with various aqueous and organic solvents. These were tested for immediate and delayed hypersensitivity reactions in guinea pigs previously sensitised to pyrethrum by single subcutaneous injection of the ground flowers suspended in Freund's complete adjuvant. Strong reactions were elicited by various aqueous extracts of the flowers; the allergens are of high molecular weight, being non‐dialysable. A hexane extract (similar to pyrethrum oleoresin) produced a moderate reaction, but a commercially refined pyrethrum extract proved negative.

An extract of the spent flowers with methylene chloride showed irritant effects in unsensitised guinea pigs.
Gelatin as a carrier for S2‐cyanoethyl N‐[(methylcarbamoyl)oxy]thioacetimidate, an experimental molluscicide
Authors: Stephenson J. W.
Published: November 2006

Gelatin and gelatin hardened by formaldehyde, were immersed in water or exposed out of doors on bare soil, and their resistance to these treatments is described. It is shown that the water‐soluble, protein‐rich, constituents of wheat bran are palatable to slugs and can be used as an arrestant. Hardened gelatin made with aqueous wheat bran extract in which the toxicant was incorporated did not disintegrate and continued to kill slugs over a large period in wet weather.
Effects of aliphatic acids on the metabolism and potency of fenitrothion in flour beetles
Authors: Rowlands D. G. , Dyte C. E.
Published: November 2006

Formic, acetic, or n‐propionic acid applied with fenitrothion to Tribolium castaneum, inhibited the production of both fenitroxon and O‐desmethyl fenitrothion, but did not appear to affect metabolic attack on the P‐O‐phenyl link. These effects are comparable to those of some pyrethrum synergists. The toxicity of fenitrothion was synergised by formic or acetic acid, and antagonised by propionic acid, but these effects on potency were slight.
Toxicity of some pyrethroids to the adult desert locust, Schistocerca gregaria forsk
Authors: Ford M. G. , Reay R. C.
Published: November 2006

The toxicity of a number of topically applied pyrethroids has been tested against adult male desert locusts, Schistocerca gregaria: the most potent proved to be 5‐benzyl‐3‐furylmethyl (+)‐trans‐chrysanthemate (bioresmethrin) with a weighted mean LD50 of 4.0 μg/g. The remaining compounds may be ranked in order of toxicity as follows: 5‐benzyl‐3‐furylmethyl (±)‐cis‐trans‐chrysanthemate (resmethrin) > 4‐allyl‐2,6‐dimethyl‐benzyl(+)‐trans‐chrysanthemate > 4‐allylbenzyl (+)‐trans‐chrysanthemate > 2,4,6‐trimethylbenzyl (+)‐cis‐trans‐chrysanthemate > 2,3,4‐trimethylbenzyl (+)‐cis‐trans‐chrysanthemate > 2,4‐dimethylbenzyl (±)‐cis‐trans‐chrysanthemate; 2‐methylbenzyl (±)‐cis‐trans‐chrysanthemate. A small factor of synergism (4.2) was obtained with bioresmethrin following pre‐treatment with sesamex, but with resmethrin the synergistic ratio (1.6) was of little practical significance.
Fungitoxicity of acid and alkaline hydrolysis products of drazoxolon and related arylhydrazonoisoxazolones
Authors: Lehtonen K. , Summers L. A. , Carter G. A.
Published: November 2006

Drazoxolon and related 3‐methyl‐4‐arylhydrazono‐5‐isoxazolones are hydrolysed by acid to 2‐arylhydrazono‐3‐oxobutyric acids and by alkali to 1‐arylhydrazono‐2‐hydroxyiminopropanes and 2‐arylhydrazono‐3‐hydroxyiminobutyric acids. Although many of the hydrolysis products show good antifungal activity in spore germination tests they are inferior to drazoxolon as protectants for the control of Uromyces fabae on broad bean and as protectants and eradicants against Erysiphe graminis on wheat. Neither drazoxolon nor its hydrolysis products show much activity as therapeutants.
The analysis of crops and soils for the triazine herbicide cyanazine and some of its degradation products. II. Results
Authors: Beynon K. I. , Bosio P. , Elgar K. E.
Published: November 2006

Crops and soils from field trials in 1967–1970 in several countries have been analysed for residues of the triazine herbicide cyanazine (‘BLADEX’

Shell Registered Trade Mark.

a or ‘FORTROL’a' 2‐chloro‐4‐(1‐cyano‐1‐methylethylamino)‐6‐ethylamino‐1,3,5‐triazine) and for its degradation products 2‐chloro‐4‐(1‐carbarmoyl‐1‐methylethylamino)‐6‐ethylamino‐1,3,5‐triazine (II), 2‐chloro‐4‐(1‐cyano‐1‐methylethylamino)‐6‐amino‐1,3,5‐triazine (V) and 2‐chloro‐4‐(1‐carbonyl‐1‐methylethylamino)‐6‐amino‐1,3,5‐triazine (VI).

The time for the concentration of cyanazine in soils to fall to half the initial value was in the range 1.3 to 5 weeks with a mean value of 2.4 weeks. The rate of loss was not affected by sparse crop cover and there was some indication that the rate was greater under moist soil conditions.

Residues of up to 0.5 part/million of (II) and up to 0.08 part/million of (VI) were detected in soils at 4 weeks from cyanazine application at 2 kg/ha. The residues of cyanazine and the degradation products declined rapidly and were 0.07 part/million or less at 16 weeks from treatment. Repeated annual applications did not lead to a detectable build up of residues in soil.

Neither residues of cyanazine nor those of (II), (V) or (VI) could be detected in a wide range of crops harvested from soil treated in accordance with the likely recommendations and the limits of detectability were 0.01 to 0.04 part/million.
Fumigation of citrus fruit with ethylene dibromide: Desorption of residues and ethylene evolution
Authors: Alumot E. , Chalutz E.
Published: November 2006

The desorption of ethylene dibromide (EDB) residues from fumigated Shamouti citrus fruits is fitted by a single exponential equation at 17 and 22°C, and by an equation with a double exponential term at 5°C. Establishing the rate constant enables calculation of the initial concentration of EDB residues in the peel, thereby obtaining information on conditions during fumigation and on the possibility of peel injury development in the fumigated fruit. Healthy, harvested Shamouti citrus fruit evolve ethylene at a low rate, which is increased by EDB fumigation. Fumigated fruit in which EDB caused peel injury evolved ethylene at a higher rate than fumigated fruit in which peel injuries did not develop. This information could be used for predicting peel injuries and in studies aimed at a better understanding of the processes leading to the development of peel injuries in fumigated citrus fruit.
Effect of sodium 2‐phenylphenate applied in wax coatings on appearance of injuries in citrus fruit
Authors: Rajzman Anna , Apelbaum A. , Heller Hana
Published: November 2006

Citrus fruits were treated with wax coatings containing sodium 2‐phenylphenate tetrahydrate (SOPP) and stored at 10 °C. No injuries appeared during 30 days' storage in Valencia oranges sprayed with waxes containing up to 4.75% of SOPP, or during 70 days' storage in Shamouti oranges and in grapefruit dipped in waxes containing up to 2.16% of SOPP. In Shamouti oranges and grapefruit dipped in waxes containing 3.1 to 3.88% of SOPP, injuries appeared at the beginning of storage. In non‐injured fruits, the amounts of SOPP applied by waxing did not exceed 74.7 μg/cm2 of the fruit surface and the 2‐phenylphenol (OPP) residues in the fruits did not exceed 36.8 parts/million; in injured fruits the amounts of SOPP applied varied between 105.1 and 211.3 μg/cm2 and the OPP residues between 41.5 and 123.6 parts/million. In non‐injured fruit the amount of wax applied did not exceed 3.46 μl/cm2; in injured fruits the figure varied between 3.19 and 6.2 μg/cm2, suggesting that the wax coating concentrates at some places on the peel, causing injuries to the fruit. In injured grapefruit 7.93 μl/cm2 of wax was found on the injured part of the peel, and 3.21 μl/cm2 on the non‐injured part, so that 124.6 μg of SOPP/cm2 corresponding to 61.6 parts/million of OPP in the fruit was applied to the fruit without causing injuries.
Phloem transport in Ricinus
Authors: Milburn John A.
Published: November 2006

Recently, Ricinus has been used extensively to investigate the mechanism of phloem transport. This work is reviewed. In many respects, both anatomically and physiologically, Ricinus seems to approach the ideal for work on phloem physiology. Its anatomy is typical of many plants so that valid comparisons can probably be drawn with other species. However, the actual measurement of the proportion of sieve tubes is difficult.

Exudation from the wounded phloem can be controlled by a variety of treatments. It seems to represent the true phloem transport stream, and from all observations to date seems to fulfill the requirements of the pressure flow theory. The actual velocity of the mass flow of sap by displacement has been shown to be very considerable, as might be expected on the pressure flow theory, and to become polarised towards a wound from each side in roughly equal proportions. There seem to be considerable concentration gradients in the stem, as indicated by refractometry in the direction one would expect on the basis of pressure flow.

Attention has been drawn to the mechanism by which exudation is prevented by the plant. Ricinus seems ideal material for investigations into the sealing mechanisms which can curtail or permit exudation on wounding. Probably, when these systems are understood we can solve the ultimate problem of the condition of intact sieve plate pores.