{"title":"Roles of aorta, ostia and tracheae in heartbeat and respiratory gas exchange in pupae of Troides rhadamantus Staudinger 1888 and Ornithoptera priamus L. 1758 (Lepidoptera, Papilionidae)","authors":"S.K Hetz , E Psota , L.T Wasserthal","doi":"10.1016/S0020-7322(99)00013-6","DOIUrl":"10.1016/S0020-7322(99)00013-6","url":null,"abstract":"<div><p>In non-diapausing pupae of the two birdwing butterfly species <em>Troides rhadamantus</em> and <em>Ornithoptera priamus</em> (Lepidoptera, Papilionidae) heart activity and CO<sub>2</sub> release rates were measured simultaneously within the initial half of pupal development. Heartbeat patterns in these pupae consist of three different types of activity: Continuous forward-pulse periods of different duration with a frequency range of about 0.25–0.52 s<sup>−1</sup>, continuous backward-pulse periods with lower frequencies (0.15–0.29 s<sup>−1</sup>) and intermittent backward-pulse periods when short series of three to 10 single heartbeats at frequencies of 0.12–0.35 s<sup>−1</sup> alternated with heart pauses of 2–10 min. CO<sub>2</sub> release was discontinuous (CFO-type) from about four to 12 days after pupation in <em>Troides rhadamantus</em> and from about four to 18 days in <em>Ornithoptera priamus</em>. Mean CO<sub>2</sub> release rates were very low in both species (10–30 nmol g<sup>−1</sup> min<sup>−1</sup>). After this period, heart pauses occurred more frequently, probably indicating the onset of metamorphosis and the beginning partial histolysis of the heart. Infrared-optical and thermometrical measurements of heartbeat indicated that haemolymph transport within the dorsal vessel in forward direction is more effective than in backward direction. This is deduced from the higher heartbeat frequency and heartbeat amplitude of the forward pulsations. Results from ultrasonic doppler velocimetry suggest that haemolymph flow velocity is highest during the relatively long diastasis of 2–3 s (30–40 mm s<sup>−1</sup>), while minimum particle speed (about 20 mm s<sup>−1</sup>) is at the end of systole and the beginning of diastole. This would mean that haemolymph velocity is highest between two consecutive peristaltic waves. In contrast to the haemolymph velocity, the speed of the peristaltic wave measured with the infrared transmission technique was lower (about 8.4–22 mm s<sup>−1</sup> in <em>Troides</em>, 10–23 mm s<sup>−1</sup> in <em>Ornithoptera</em>) and remained constant during forward pulse periods. During backward beating the speed was lower (8–20 mm s<sup>−1</sup> in <em>Troides</em>, 9–17 mm s<sup>−1</sup> in <em>Ornithoptera</em>) and decreased during backward pulse periods. During day two to seven in <em>Troides</em> and day three to nine in <em>Ornithoptera,</em> spiracular opening periods coincided with changes in heartbeat direction from backward to forward pulsations. A possible influence is the more efficient convective haemolymph mixing in the haemocoel during forward heartbeat. The mixing allows to bring the haemolymph in close contact with the tracheal system where the discharge of CO<sub>2</sub> takes place. Heartbeat may therefore serve for shortening the diffusion pathways for a rapid transition into the tracheal system during the open period of the spiracles.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"28 1","pages":"Pages 131-144"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(99)00013-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87389777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Functional morphology of the heart and of a new cephalic pulsatile organ in the blowfly Calliphora vicina (Diptera: Calliphoridae) and their roles in hemolymph transport and tracheal ventilation","authors":"Lutz Thilo Wasserthal","doi":"10.1016/S0020-7322(99)00012-4","DOIUrl":"10.1016/S0020-7322(99)00012-4","url":null,"abstract":"<div><p>In the blowfly <em>Calliphora vicina</em> (Diptera: Calliphoridae), the morphology of the dorsal vessel and of a new cephalic accessory pulsatile organ (CPO) were analysed with light-microscopic, SEM and TEM techniques. The CPO and neck aorta are reconstructed 3-dimensionally by computer-aided design. The pulse activity of the CPO and of the heart was measured in intact flies over periods of several hours or days using contact-thermography with laser beam heat-marking. The intratracheal pressure was simultaneously measured at the anterior thoracic spiracle. The dorsal vessel is constructed of pairs of left–right alternating cells. Its enlarged chamber in the anterior abdomen contains two pairs of incurrent ostia, its posterior narrower heart tube possesses three pairs of incurrent ostia and paired caudal excurrent openings. The aorta opens with a funnel-like opening in the neck. Proportions, arrangement and ultrastructure of the aorta, heart cells and pericardial muscles are described. Cushionlike sarcoplasmic protrusions of heart cells (pair no. 17) probably function as internal valves. The neck aorta is constructed of a cuticular ‘roof’ deviating from the dorsal neck membrane and a ventral longitudinal muscle ‘floor’. The aorta is not kept open because of missing muscle or connective tissue strands. The underside of the CPO is fused with air sacs that function as antagonists to the muscles. The heart reverses its beat periodically in resting and active flies. During the longer forward-pulse periods, mean frequency is lower (about 3.0 Hz at Ta 20°C), during the shorter backward periods mean frequency is higher (4.6 Hz). The CPO beats only during forward-pulse periods of the heart with an independent and slower pulse rate (1.8 Hz). The CPO-pulses produce positive pressure pulses at the anterior thoracic spiracle. During backward-pulse periods of the heart and pulse pause of the CPO, a continuous negative pressure arises at the thoracic spiracle instead of pressure pulses. The intimate connection of an accessory pulsatile organ with tracheal air sacs makes it work as a bifunctional pump for hemolymph distribution and tracheal ventilation. Neurosecretory and synapsing innervation of the CPO in connection with aorta, heart and pericardial septum muscle innervation suggest that both organs are regulated and that the duration of their periods is neuronally coordinated.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"28 1","pages":"Pages 111-129"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(99)00012-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73442992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ferdinando Bin , Felix Wäckers , Roberto Romani , Nunzio Isidoro
{"title":"Tyloids in Pimpla turionellae (L.) are release structures of male antennal glands involved in courtship behaviour (Hymenoptera: Ichneumonidae)","authors":"Ferdinando Bin , Felix Wäckers , Roberto Romani , Nunzio Isidoro","doi":"10.1016/S0020-7322(99)00015-X","DOIUrl":"10.1016/S0020-7322(99)00015-X","url":null,"abstract":"<div><p>Morphological and behavioural studies were performed on male antennal tyloids of <em>Pimpla turionellae</em> (L.) (Hymenoptera: Ichneumonidae). S.E.M. and T.E.M. investigations revealed that tyloids, located on 8th and 9th male antennomeres, are release structures of integumentary glands rather than sensory organs. These are bicellular secretory units consisting of one secretory cell, with a well-developed receiving canal, and a canal cell. The latter forms the evacuating canal, which connects the receiving canal to the external pore on the tyloids. Observations of mating behaviour showed that during the precopulatory phase, males typically perform antennal strokes during which the secretion containing tyloids comes in direct contact with the female antennae. Stroking intensity seemed to be correlated with female receptiveness, being more prolonged when females are initially unreceptive. When encountering receptive females, male stroking is usually limited or even omitted entirely. Results from behavioural comparisons between unmanipulated pairs and pairs in which male tyloids had been coated with glue, clearly indicate that the secretion mediates mate acceptance in females.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"28 1","pages":"Pages 61-68"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(99)00015-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84597679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparative morphology of the spiracles of the Papilionidae, Sphingidae, and Saturniidae (Insecta: Lepidoptera)","authors":"A Schmitz , L.T Wasserthal","doi":"10.1016/S0020-7322(98)00033-6","DOIUrl":"10.1016/S0020-7322(98)00033-6","url":null,"abstract":"<div><p>The morphology, ultrastructure, and innervation of the spiracles of the instars and adults of representatives of three lepidopteran families were examined: <em>Ornithoptera priamus poseidon</em> and <em>Pachliopta aristolochiae</em> (Papilionidae), <em>Attacus atlas</em> (Saturniidae), and <em>Acherontia atropos</em> (Sphingidae).</p><p>Peritreme and atrium show stage- and family-specific structures for protecting the internal valve apparatus. The gross morphology of the cuticular valve mechanism is uniform within the three families, consisting of a rigid bow and a movable bar with a lever. In adult Papilionidae, all cuticular parts (bow, bar and lever) of the valve are innervated by multipolar dendrites. Internal or external cuticular chemo- or hygroreceptors, which could participate in the regulation of respiration, could not be detected in any stage. The closing muscle inserts between the tip of the lever and the base of the bar, and is innervated only by motor neurons. The elasticity of the cuticular system and an opener are the antagonists to the closing muscle. The spiracular opener of the adult Papilionidae and of all instars of the moths is an elastic ligament. The opener of the larval and pupal spiracles of the Papilionidae, however, is a single thickened muscle fiber surrounded by an elastic sheath of connective tissue. As it contains motor and multipolar sensory neurons, we assume that it may function as a stretch receptor for controlling the spiracular opening state.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"28 1","pages":"Pages 13-26"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(98)00033-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89713427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Structure of identified neurons innervating the lateral cardiac nerve cords in the migratory locust, Locusta migratoria migratorioides (Reiche and Fairmaire) (Orthoptera, Acrididae)","authors":"Peter Bräunig","doi":"10.1016/S0020-7322(99)00009-4","DOIUrl":"10.1016/S0020-7322(99)00009-4","url":null,"abstract":"<div><p>Our knowledge about the morphology of neurons innervating the lateral cardiac nerve cords (LCNCs) in migratory locusts, <em>Locusta migratoria migratorioides</em> (R. and F.) (Orthoptera, Acrididae) has increased considerably during recent years, mainly owing to immunocytochemical studies using antisera directed against members of insect neuropeptide families. In principle, there are three morphological types of neurons located within the CNS, which innervate the LCNCs in locusts: abdominal ganglia contain (i) bilaterally projecting, possibly unpaired neurons (BPNs) and (ii) paired, unilaterally projecting neurons. In addition, (iii) the LCNCs receive innervation from a pair of neurons, which is located within the suboesophageal ganglion. The axons of all three types of neurons project into the LCNCs via the segmental heart nerves, the most distal extensions of the dorsal segemental nerves of abdominal ganglia. When estimating the number of axons contained in one segmental heart nerve and formed by all central neurons so far identified, this number exceeds the number of axon profiles previously seen using the electron microscope. This indicates that most, or perhaps all central neurons projecting into the LCNCs, have been identified in these insects.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"28 1","pages":"Pages 81-89"},"PeriodicalIF":0.0,"publicationDate":"1999-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(99)00009-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84954504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Enno Merivee , Märt Rahi , José Bresciani , Hans Peter Ravn , Anne Luik
{"title":"Antennal sensilla of the click beetle, limonius aeruginosus (OLIVIER) (COLEOPTERA: ELATERIDAE)","authors":"Enno Merivee , Märt Rahi , José Bresciani , Hans Peter Ravn , Anne Luik","doi":"10.1016/S0020-7322(98)00023-3","DOIUrl":"10.1016/S0020-7322(98)00023-3","url":null,"abstract":"<div><p>Antennal sensilla typology, number and distribution of the click beetle <em>Limonius aeruginosus</em> (Olivier) (Coleoptera: Elateridae) were studied using scanning electron microscopy. The serrate antennae of both sexes of <em>L. aeruginosus</em> consist of the scape, pedicel and of the flagellum which is composed of 9 flagellomeres. In both sexes, 5 types of sensilla basiconica, 1 type of sensilla trichodea, 1 type of sensilla chaetica, 1 type of sensilla campaniformia and Böhm sensilla were distinguished. No remarkable sexual differences in the types, numbers and distribution of sensilla were found on the antennae, except for the sensilla basiconica type II. The average number of sensilla basiconica type II on the antennae of the male beetle surpassed that on the antennae of the female beetle (3562 and 108 pegs, respectively). It is suggested that this type of sensilla on the male beetles antennae is responsible for the reception of the sex pheromone produced by the female beetle.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 4","pages":"Pages 311-318"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(98)00023-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81568484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Structure of ovaries and oogenesis in the snow scorpionfly boreus hyemalis (LINNE)(MECOPTERA : BOREIDAE)","authors":"Szczepan M Bilinski , Jürgen Büning","doi":"10.1016/S0020-7322(98)00026-9","DOIUrl":"10.1016/S0020-7322(98)00026-9","url":null,"abstract":"<div><p>The ovaries of the snow scorpionfly, <em>Boreus hyemalis</em> (Mecoptera : Boreidae) are panoistic and comprise 7–8 ovarioles. Each ovariole consists of a terminal filament, elongated vitellarium, and ovariole stalk (=pedicel) only ; in adult specimens, functional germaria are absent. Five consecutive stages of oogenesis i.e., early, mid- and late previtellogenesis, vitellogenesis, and choriogenesis have been distinguished in imagines. Oocyte nuclei (=germinal vesicles) of previtellogenic oocytes contain numerous polymorphic multiple nucleoli (or nucleolar masses), endobodies, and chromatin aggregations. Next to the nuclear envelope, large accumulations of nuage material are localized. The ooplasm of late previtellogenic oocytes is differentiated into transparent (perinuclear) and opaque (peripheral) regions. Ultrastructural investigations have revealed that within the latter, abundant ribosomes as well as mitochondria, elements of endoplasmic reticulum, Golgi complexes, annulate lamellae, symbiotic bacteroids, lipid droplets and distinctive accumulations of membrane-free clathrin-like cages are present. Early- and mid previtellogenic oocytes are invested with flat somatic cells that gradually transform into a follicular epithelium. In the vicinity of 3-cell junctions, neighbouring follicular cells are joined by narrow intercellular bridges. During late previtellogenesis, numerous microvilli develop on the oocyte surface. They interdigitate with morphologically similar but less frequent microvilli of the follicular cells. Concurrently, first endocytotic vesicles appear in the cortical ooplasm. In the context of presented results, the phylogenetic relationships between mecopterans (boreids) and fleas are discussed.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 4","pages":"Pages 333-340"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(98)00026-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88679473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Microspines in the alimentary canal of arthropoda, onychophora, annelida","authors":"Richard J Elzinga","doi":"10.1016/S0020-7322(98)00027-0","DOIUrl":"10.1016/S0020-7322(98)00027-0","url":null,"abstract":"<div><p>The presence and variation of microspines within the foregut and hindgut of the taxa Arthropoda, Onycophora, and Annelida were presented. Microspines appear to be sympleisiomorphic to the Arthropoda sensu stricto. Unispinose microspines constitute the original ancestral condition, and these have been retained and variously modified within the classes to aid in filtering ingested food, food movement through the gut and retain symbionts, and possibly protect the cellular linings of the gut in particulate food eaters.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 4","pages":"Pages 341-349"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(98)00027-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84926081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mouthpart sensilla of cave species of australian paratemnopteryx cockroaches (BLATTARIA : BLATTELLIDAE)","authors":"Roger G Bland , David P Slaney , Philip Weinstein","doi":"10.1016/S0020-7322(98)00021-X","DOIUrl":"https://doi.org/10.1016/S0020-7322(98)00021-X","url":null,"abstract":"<div><p>The external morphology and distribution of sensilla on maxillary and labial palpi are described for 3 Australian cave-dwelling cockroach species, <em>Paratemnopteryx stonei</em>, <em>P. howarthi</em>, and <em>P</em>. sp. nov (Blattaria : Blattellidae), using scanning electron microscopy. The apex of the maxillary palpus expands ventrally into a flexible pad with a distinct sensillar field. The total number of sensilla ranges from 1045 (males)–1486 (females). Sensillar fields of females are larger and contain more sensilla than those of the males, although the density of sensilla is usually equal or greater for males. Papilla-like groove-and-slit chemoreceptors comprise 93–97% of the sensilla. Two types of trichoid sensilla occur along with bifurcuted sensilla and rare basiconic sensilla that are poreless and have an inflexible socket. Chaetic sensilla occur on all species and several thousand pectinate scales, with bulbous bases, and spicules are present in large fields on each side of the sensillar field. The apex of the labial palpus is only slightly expanded into a sensillar field. Sensillar diversity is similar to the maxillary palpus but there are only 5–29% as many sensilla, the number ranging from 97 (males)–346 (females). Sensillar fields of females are slightly to much larger than those of males but the sensillar density is equal between the sexes or greater on males. Two types of trichoid and one or two types of basiconic sensilla occur on each species. Chaetic chemoreceptors are present along with three types of non-socket spines. Sensilla varied moderately in morphology and gender-related abundance from those on epigean cockroach species.</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 4","pages":"Pages 291-300"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(98)00021-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92050977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Structure of ovaries of scale insects: ii. margarodidae (INSECTA, hemiptera, COCCINEA)","authors":"Teresa Szklarzewicz","doi":"10.1016/S0020-7322(98)00024-5","DOIUrl":"10.1016/S0020-7322(98)00024-5","url":null,"abstract":"<div><p>The paired, spindle-shaped ovaries of the second instar of the Polish cochineal, <em>Porphyrophora polonica</em> (L.) (Hemiptera: Coccinea) are filled with cystocytes that are arranged into rosettes. In the centre of each rosette, there is a polyfusome. During the third instar, cystocytes differentiate into oocytes and trophocytes (nurse cells) and ovarioles are formed. Ovaries of adult females are composed of about 300 ovarioles of the telotrophic type. Each of them is subdivided into a tropharium (trophic chamber) and vitellarium. The tropharium consists of trophocytes and arrested oocytes that may develop. The number of germ cells in the trophic chambers varies from 11 to 18 even between the ovarioles of the same ovary. The obtained results seem to confirm the concept of a monophyletic origin of the primitive scale insects (Archaeococcoidea).</p></div>","PeriodicalId":100701,"journal":{"name":"International Journal of Insect Morphology and Embryology","volume":"27 4","pages":"Pages 319-324"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0020-7322(98)00024-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91481555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}