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Selected AbstractsThe Hox gene complement of acoel flatworms, a basal bilaterian cladeEVOLUTION AND DEVELOPMENT, Issue 3 2004Charles E. Cook Summary Several molecular data sets suggest that acoelomorph flatworms are not members of the phylum Platyhelminthes but form a separate branch of the Metazoa that diverged from all other bilaterian animals before the separation of protostomes and deuterostomes. Here we examine the Hox gene complement of the acoel flatworms. In two distantly related acoel taxa, we identify only three distinct classes of Hox gene: an anterior gene, a posterior gene, and a central class gene most similar to genes of Hox classes 4 and 5 in other Bilateria. Phylogenetic analysis of these genes, together with the acoel caudal homologue, supports the basal position of the acoels. The similar gene sets found in two distantly related acoels suggest that this reduced gene complement may be ancestral in the acoels and that the acoels may have diverged from other bilaterians before elaboration of the 8- to 10-gene Hox cluster that characterizes most bilaterians. [source] High humidity suppresses ssi4 -mediated cell death and disease resistance upstream of MAP kinase activation, H2O2 production and defense gene expressionTHE PLANT JOURNAL, Issue 6 2004Fasong Zhou Summary The Arabidopsis ssi4 mutant, which exhibits spontaneous lesion formation, constitutive expression of pathogenesis-related (PR) genes and enhanced resistance to virulent bacterial and oomycete pathogens, contains a gain-of-function mutation in a TIR-NBS-LRR type R gene. Epistatic analyses revealed that both PR gene expression and disease resistance are activated via a salicylic acid (SA)- and EDS1 -dependent, but NPR1 - and NDR1 -independent signaling pathway. In this study, we demonstrate that in moderate relative humidity (RH; 60%), the ssi4 mutant accumulates H2O2 and SA prior to lesion formation and displays constitutive activation of the MAP kinases AtMPK6 and AtMPK3. It also constitutively expresses a variety of defense-associated genes, including those encoding the WRKY transcription factors AtWRKY29 and AtWRKY6, the MAP kinases AtMPK6 and AtMPK3, the powdery mildew R proteins RPW8.1 and RPW8.2, EDS1 and PR proteins. All of these ssi4 -induced responses, as well as the chlorotic, stunted morphology and enhanced disease resistance phenotype, are suppressed by high RH (95%) growth conditions. Thus, a humidity sensitive factor (HSF) appears to function at an early point in the ssi4 signaling pathway. All ssi4 phenotypes, except for MAP kinase activation, also were suppressed by the eds1-1 mutation. Thus, ssi4 -induced MAP kinase activation occurs downstream of the HSF but either upstream of EDS1 or on a separate branch of the ssi4 signaling pathway. SA is a critical signaling component in ssi4 -mediated defense responses. However, exogenously supplied SA failed to restore lesion formation in high RH-grown ssi4 plants, although it induced defense gene expression. Thus, additional signals also are involved. [source] Crystallization and preliminary X-ray analysis of PaaAC, the main component of the hydroxylase of the Escherichia coli phenylacetyl-coenzyme A oxygenase complexACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2010Andrey M. Grishin The Escherichia coli paa operon encodes enzymes of the phenylacetic acid-utilization pathway that metabolizes phenylacetate in the form of a coenzyme A (CoA) derivative. The phenylacetyl-coenzyme A oxygenase complex, which has been postulated to contain five components designated PaaABCDE, catalyzes ring hydroxylation of phenylacetyl-CoA. The PaaAC subcomplex shows low sequence similarity to other bacterial multicomponent monooxygenases (BMMs) and forms a separate branch on the phylogenetic tree. PaaAC, which catalyzes the hydroxylation reaction, was purified and crystallized in the absence of a bound ligand as well as in complexes with CoA, 3-hydroxybutyryl-CoA, benzoyl-CoA and the true substrate phenylacetyl-CoA. Crystals of the ligand-free enzyme belonged to space group P212121 and diffracted to 2.65,Å resolution, whereas complexes with CoA and its derivatives crystallized in space group P41212 and diffracted to ,2.0,Å resolution. PaaAC represents the first crystallized BMM hydroxylase that utilizes a CoA-linked substrate. [source] Two bellies of the coracobrachialis muscle associated with a third head of the biceps brachii muscleCLINICAL ANATOMY, Issue 5 2001Mostafa M. El-Naggar Abstract Reports that describe the abnormalities and complexities of the anatomy of the arm are important with regard to surgical approaches. This case study reports a combined abnormal form of the coracobrachialis and biceps brachii muscles of the left arm of an adult male cadaver that was detected during the educational gross anatomy dissections of embalmed cadavers. The coracobrachialis muscle demonstrated two bellies which formed shortly inferior to its origin from the coracoid process of the scapula. One belly inserted into the middle of the antero-medial surface of the humerus, whereas the other belly inserted into the medial head of the triceps brachii muscle. The musculocutaneous nerve passed between the two bellies, giving a separate branch to each. We suggest that the two bellies of the coracobrachialis muscle may represent the incompletely fused short heads of the ancestral muscle. The biceps brachii muscle showed a third head, which originated mainly from the antero-medial surface of the humerus and partially from an aponeurosis belonging to the medial head of the triceps brachii muscle. These observations were confined to the left upper limb and were not accompanied by any other abnormality. Clin. Anat. 5:379,382, 2001. © 2001 Wiley-Liss, Inc. [source] Effects of substrate geometry on growth cone behavior and axon branchingDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2006Ginger S. Withers Abstract At the leading edge of a growing axon, the growth cone determines the path the axon takes and also plays a role in the formation of branches, decisions that are regulated by a complex array of chemical signals. Here, we used microfabrication technology to determine whether differences in substrate geometry, independent of changes in substrate chemistry, can modulate growth cone motility and branching, by patterning a polylysine grid of narrow (2 or 5 ,m wide) intersecting lines. The shape of the intersections varied from circular nodes 15 ,m in diameter to simple crossed lines (nodeless intersections). Time-lapse recordings of cultured hippocampal neurons showed that simple variations in substrate geometry changed growth cone shape, and altered the rate of growth and the probability of branching. When crossing onto a node intersection the growth cone paused, often for hours, and microtubules appeared to defasciculate. Once beyond the node, filopodia and lamellipodia persisted at that site, sometimes forming a collateral branch. At nodeless intersections, the growth cone passed through with minimal hesitation, often becoming divided into separate areas of motility that led to the growth of separate branches. When several lines intersected at a common point, growth cones sometimes split into several subdivisions, resulting in the emergence of as many as five branches. Such experiments revealed an intrinsic preference for branches to form at angles less than 90°. These data show that simple changes in the geometry of a chemically homogeneous substrate are detected by the growth cone and can regulate axonal growth and the formation of branches. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1183,1194, 2006 [source] The times they are a changinJOURNAL OF NURSING MANAGEMENT, Issue 5 2009Cert Ed, MIKE THOMAS PhD Aim, A discussion paper outlining the potential for a multi-qualified health practitioner who has undertaken a programme of study incorporating the strengths of the specialist nurse with other professional routes. Background and rationale, The concept and the context of ,nursing' is wide and generalized across the healthcare spectrum with a huge number of practitioners in separate branches, specialities and sub-specialities. As a profession, nursing consists of different groups in alliance with each other. How different is the work of the mental health forensic expert from an acute interventionalist, or a nurse therapist, from a clinical expert in neurological deterioration? The alliance holds because of the way nurses are educated and culturalized into the profession, and the influence of the statutory bodies and the context of a historical nationalized health system. This paper discusses the potential for a new type of healthcare professional, one which pushes the intra- and inter-professional agenda towards multi-qualified staff who would be able to work across current care boundaries and be more flexible regarding future care delivery. In September 2003, the Nursing and Midwifery Council stated that there were ,more than 656 000 practitioners' on its register and proposed that from April 2004, there were new entry descriptors. Identifying such large numbers of practitioners across a wide range of specialities brings several areas of the profession into question. Above all else, it highlights how nursing has fought and gained recognition for specialisms and that through this, it may be argued client groups receive the best possible ,fit' for their needs, wants and demands. However, it also highlights deficits in certain disciplines of care, for example, in mental health and learning disabilities. We argue that a practitioner holding different professional qualifications would be in a position to provide a more holistic service to the client. Is there then a gap for a ,new breed' of practitioner; ,a hybrid' that can achieve a balanced care provision to reduce the stress of multiple visits and multiple explanations? Methods, Review of the literature but essentially informed by the authors personal vision relating to the future of health practitioner education. Implications for nursing management, This article is of significance for nurse managers as the future workforce and skill mix of both acute and community settings will be strongly influenced by the initial preregistration nurse education. [source] Novel ,-conotoxins identified by gene sequencing from cone snails native to Hainan, and their sequence diversityJOURNAL OF PEPTIDE SCIENCE, Issue 11 2006Sulan Luo Abstract Conotoxins (CTX) from the venom of marine cone snails (genus Conus) represent large families of proteins, which show a similar precursor organization with surprisingly conserved signal sequence of the precursor peptides, but highly diverse pharmacological activities. By using the conserved sequences found within the genes that encode the ,-conotoxin precursors, a technique based on RT-PCR was used to identify, respectively, two novel peptides (LiC22, LeD2) from the two worm-hunting Conus species Conus lividus, and Conus litteratus, and one novel peptide (TeA21) from the snail-hunting Conus species Conus textile, all native to Hainan in China. The three peptides share an ,4/7 subfamily ,-conotoxins common cysteine pattern (CCX4CX7C, two disulfide bonds), which are competitive antagonists of nicotinic acetylcholine receptor (nAChRs). The cDNA of LiC22N encodes a precursor of 40 residues, including a propeptide of 19 residues and a mature peptide of 21 residues. The cDNA of LeD2N encodes a precursor of 41 residues, including a propeptide of 21 residues and a mature peptide of 16 residues with three additional Gly residues. The cDNA of TeA21N encodes a precursor of 38 residues, including a propeptide of 20 residues and a mature peptide of 17 residues with an additional residue Gly. The additional residue Gly of LeD2N and TeA21N is a prerequisite for the amidation of the preceding C -terminal Cys. All three sequences are processed at the common signal site -X-Arg- immediately before the mature peptide sequences. The properties of the ,4/7 conotoxins known so far were discussed in detail. Phylogenetic analysis of the new conotoxins in the present study and the published homologue of ,4/7 conotoxins from the other Conus species were performed systematically. Patterns of sequence divergence for the three regions of signal, proregion, and mature peptides, both nucleotide acids and residue substitutions in DNA and peptide levels, as well as Cys codon usage were analyzed, which suggest how these separate branches originated. Percent identities of the DNA and amino acid sequences of the signal region exhibited high conservation, whereas the sequences of the mature peptides ranged from almost identical to highly divergent between inter- and intra-species. Notably, the diversity of the proregion was also high, with an intermediate percentage of divergence between that observed in the signal and in the toxin regions. The data presented are new and are of importance, and should attract the interest of researchers in this field. The elucidated cDNAs of these toxins will facilitate a better understanding of the relationship of their structure and function, as well as the process of their evolutionary relationships. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd. [source] Arterial supply to the sciatic nerve in the gluteal regionCLINICAL ANATOMY, Issue 1 2008Effrossyni Georgakis Abstract The arterial supply to the sciatic nerve was investigated in 20 human lower limbs (10 right, 10 left) from 20 cadavers (14 females, aged 84 ± 9.6 years, range 66,95 years: 6 males, aged 80 ± 8.2 years, range 70,90 years). In all limbs examined at least 1 sciatic artery could be identified supplying the sciatic nerve in the gluteal region. In total 28 sciatic arteries were identified, of which 14 arose from the medial circumflex femoral artery, 11 from the inferior gluteal artery, 2 from the first perforating artery, and 1 from the internal pudendal artery. In 5 limbs, 2 sciatic arteries were observed, being independent branches from the medial circumflex femoral and inferior gluteal arteries in 4 limbs and separate branches of the medial circumflex femoral artery in 1 limb. In 1 limb, 4 sciatic arteries were observed: 1 from the inferior gluteal artery, 2 from the medial circumflex femoral artery, and 1 from the first perforating artery. In the remaining 14 limbs a single sciatic artery was observed, which in one case arose from the internal pudendal artery, a previously unreported observation. Clin. Anat. 21:62,65, 2008. © 2007 Wiley-Liss, Inc. [source] Bone morphology and vascularization of untreated and guided bone augmentation-treated rabbit calvaria: evaluation of an augmentation modelCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2005Christer Slotte Abstract Objectives: Cranial vault is widely used in experimental models on membranous bone healing in general, guided bone augmentation (GBA) studies being one example. To our knowledge, however, few studies on the characteristics of the untreated calvaria regarding bone density, vessel topography, and their intra/interindividual variations and associations are available. The aims of this investigation were to (1) map the large vessel topography of the skull vault, (2) describe the parietal bones of the adult rabbit histologically and morphometrically, and (3) histologically compare untreated parietal bone with parietal bone that had been treated with a GBA device. Material and methods: Ten adult untreated rabbits were microangiographed. General anesthesia was induced and the mediastinum was opened. Heparin and lidocaine were injected in the aorta followed by perfusion with India ink. After death, en bloc biopsies of the skull vault including the overlying soft tissues and dura mater were taken. The specimens were cleared with the Spalteholtz technique, microscopically examined, and digitally imaged. Thereafter, circular biopsies were harvested to obtain decalcified sections. In addition, sections from 14 GBA-treated rabbit skulls (of the same race, sex and age as the untreated animals) served as reference specimens for comparison. Histomorphometric examinations were carried out. Results: In the cleared specimens, all parietal bones were found to be supplied by one major branch of the meningeal artery. From each of these, separate branches supplied the dura wherein a fine vessel network covered the bone. No major vessels were found in the supracalvarial soft tissue. Numerous fine vessels were found within the periosteum and dura entering the cortical plates. The decalcified sections of the parietal bones revealed an outer and inner cortical plate enveloping a diploic space containing bone trabeculae, marrow tissue and larger sinusoids. Hollow connections were frequently found in both the outer and inner cortical plates in both the untreated and the GBA-treated specimens. These connections contained marrow tissue that extended to the periosteum and the dura. The morphometric measurements revealed similar proportions of cortical, trabecular, and marrow areas in the right and left untreated bones. The area of the outer cortical plate was significantly larger than the area of the inner cortical plate. Bone density was similar in the right and left untreated and GBA-treated specimens, as was the frequency and width of hollow connections through the cortical bone plates. Conclusions: The symmetry between the left and right parietal bones concerning the large vessel topography and the histomorphometric parameters assessed was high. Hollow connections in the cortical plates were frequently found. The bilateral use of the parietal bones is suggested to be reliable in experimental GBA models regarding the blood supply and bone quality. Résumé La voûte crânienne est souvent utilisée dans les modèles expérimentaux de guérison osseuse membranaire en général, l'augmentation osseuse guidée (GBA) étant un exemple. Peu d'études sur les crânes non-traités sont disponibles en ce qui concerne la densité osseuse, la topographie des vaisseaux et leurs variations intra/interindividuelles et leurs associations. Les buts de cette étude ont été 1) de cartographier la topographie des vaisseaux larges sur la voute crânienne, 2) de décrire les os pariétaux du lapin adulte histologiquement et morphométriquement et 3) de comparer histologiquement l'os pariétal non-traité avec celui traité par GBA. Dix lapins adultes non-traités ont subi une micro-angiographie. L'anesthésie générale a été effectuée et la partie médiane a été ouverte. De l'héparine et de la lidocaïne ont été injectées dans l'aorte suivies d'une perfusion avec de l'encre noire. Après la mort, des biopsies en blocs de la voûte crânienne comportant la dura mater et les tissus mous la recouvrant ont été prélevées. Les spécimens ont été estimés par la technique de Spalteholtz, examinés microscopiquement et des images digitales ont été réalisées. Des biopsies circulaires ont été prélevées pour obtenir des sections décalcifiées. Des sections de 14 crânes de lapins traités GBA (de même race, sexe et âge que les non-traités) ont servi de spécimens de référence pour comparaison. Des examens histomorphométriques ont été effectués. Dans les spécimens non-traités, tous les os pariétaux étaient irrigués par une branche majeure de l'artère méningée. De chacune de ces dernières, différentes branches abreuvaient la dura dans laquelle un réseau de vaisseau fins recouvrait l'os. Aucun vaisseau majeur n'a été trouvé dans le tissu mou ou sus-voûte. De nombreux vaisseaux fins ont été trouvés à l'intérieur du périoste et de la dura pénétrant qu'entre les bords corticaux. Les sections décalcifiées des os pariétaux ont révélé des bords corticaux interne et externe enveloppant un espace diploïque contenant de l'os trabéculaire, de la moelle osseuse et de larges sinusoïdes. Des connexions creuses étaient fréquemment trouvées tant dans les plaques corticales interne qu'externe et tant dans les spécimens non-traités que traités GBA. Ces connexions contenaient de la moelle qui allait jusqu'au périoste et la dura. Les mesures morphométriques ont révélé des proportions semblables de cortical, trabécules et moelle dans les les os non-traités. L'aire du bord cortical externe était significativement plus importante que l'aire du bord cortical interne. La densité osseuse était semblable dans les spécimens non-traités et traités GBA gauches et droits ainsi que la fréquence et la largeur des connexions creuses à travers les bords osseux corticaux. La symétrie entre les os pariétaux gauches et droits concernant la topographie des vaisseux larges et des paramètres histomorphométriques étaient importante. Les connexions creuses dans les bords corticaux était souvent trouvées. L'utilisation bilatérale des os pariétaux est proposée pour sa fiabilité dans les modèles GBA expérimentaux concernant l'apport sanguin et la qualité osseuse. Zusammenfassung Ziele:,Die Schädeldecke wird oft bei experimentellen Modellen zur bindegewebigen Knochenheilung verwendet. Ein Beispiel dafür sind Studien zur gesteuerten Knochenaugmentation (GBA). Soviel wir wissen, existieren jedoch nur wenige Studien über die Charakteristiken der unbehandelten Kalvaria bezüglich Knochendichte, Gefässtopographie und deren intra-/interindividuelle Variationen und Assoziationen. Die Ziele dieser Untersuchung waren (1) die Topographie der grossen Gefässe der Schädeldecke aufzuzeichnen, (2) die parietalen Knochen des ausgewachsenen Kaninchens histologisch und histomorphometrisch zu beschreiben, und (3) histologisch den unbehandelten parietalen Knochen mit parietalem Knochen, der mit einer GBA Einrichtung behandelt worden war, zu vergleichen. Material und Methoden:,Zehn ausgewachsene Kaninchen wurden mikroangiographisch untersucht. In Narkose wurde das Mediastinum eröffnet. Es wurde Heparin und Lidocain in die Aorta injiziert, darauf folgte die Perfusion mit India Tinte. Nach dem Tod wurden Blockbiopsien der Schädeldecke inklusive bedeckende Weichgewebe und Dura mater entnommen. Die Präparate wurden mittels der Spaltenholztechink gereinigt, mikroskopisch untersucht und digital aufgezeichnet. Danach wurden zirkuläre Biopsien gewonnen, um entkalkte Schnitte herzustellen. Zusätzlich dienten Schnitte von 14 GBA-behandelten Kaninchenschädeln (gleiche Rasse, Geschlecht und Alter wie die unbehandelten Tiere) als Referenzpräparate zum Vergleich. Es wurden histomorphometrische Untersuchungen durchgeführt. Resultate:,In den gereinigten Präparaten konnte gesehen werden, dass alle parietalen Knochen durch einen grossen Ast der Meningalarterie versorgt wurden. Separate Aeste dieser Arterie versorgten die Dura, wobei ein feines Gefässnetz den Knochen bedeckte. In den Weichgeweben auf der Kalvaria konnten keine grossen Gefässe gefunden werden. Im Periost und in der Dura waren zahlreiche feine Gefässe zu sehen, welche in die kortikalen Platten eintraten. Die entkalkten Schnitte der parietalen Knochen zeigten eine äussere und innere kortikale Platte, welche einen abgeschlossenen Raum mit Knochentrabekeln, Markgewebe und grossen Hohlräumen umschlossen. In der inneren und in der äusseren kortikalen Platte konnten oft sowohl bei den unbehandelten als auch bei den GBA-behandelten Präparaten hohle Verbindungen gefunden werden. Diese Verbindungen enthielten Markgewebe, dass sich bis zum Periost und der Dura erstreckte. Die morphometrischen Messungen zeigten sowohl in den rechten als auch in den linken unbehandelten Knochen ähnliche Proportionen zwischen kortikalem Knochen, trabekulärem Knochen und den Markarealen. Die Fläche der äusseren kortikalen Platte war signifikant grösser als die Fläche der inneren kortikalen Platte. Die Knochendichte war in den rechten und linken unbehandelten und in den GBA-behandelten Präparaten ähnlich, ebenso die Häufigkeit und die Breite der hohlen Verbindungen durch die kortikalen Platten. Schlussfolgerungen:,Die Symmetrie zwischen den rechten und linken parietalen Knochen bezüglich Topographie der grossen Gefässe und der untersuchten histomorphometrischen Parameter war gross. In den kortikalen Platten konnten häufig hohle Verbindungen gefunden werden. Es wird vorgeschlagen, dass die bilaterale Verwendung von parietalen Knochen bei experimentellen GBA-Modellen zuverlässig ist bezüglich Blutversorgung und Knochenqualität. Resumen Objetivos:,La bóveda craneal es ampliamente usada en modelos experimentales en cicatrización de hueso membranoso en general, siendo un ejemplo los estudios de regeneración ósea guiada (GBA). Que sepamos, sin embargo, se dispone de pocos estudios sobre las características del calvario no tratado con respecto a la densidad ósea, la topografía vascular, y sus variaciones intra/interindividuo y sus asociaciones. Las intenciones de esta investigación fueron (1) cartografiar la topografía de grandes vasos de la bóveda craneal, (2) describir histológica y morfométricamente los huesos parietales del conejo adulto, y (3) comparar histológicamente el hueso parietal no tratado con el hueso parietal tratado con un dispositivo de GBA. Material y Métodos:,Se llevaron a cabo microangiografías a diez conejos adultos sin tratar. Se indujo anestesia general y se abrió el mediastino Se inyectaron heparina y lidocaina en la aorta seguida por infusión de tinta de India. Tras la muerte, se tomaron biopsias en bloque de la bóveda craneal incluyendo los tejidos blandos superpuestos y de la duramadre. Los especimenes se aclararon con la técnica de Spalteholtz, se examinaron microscópicamente, y se tomaron imágenes digitales. Más adelante, se recogieron biopsias circulares para obtener secciones descalcificadas. Además, secciones de los cráneos de los conejos tratados con 14secciones descalcificadas. Además, secciones de los cráneos de los conejos tratados con 14 GBA (de la misma raza, sexo y edad que los animales no tratados) sirvieron como especimenes de referencia para la comparación. Se llevaron a cabo exámenes histomorfométricos. Resultados:,En los especimenes aclarados, todos los huesos parietales se encontró que estaban irrigados por una rama principal de la arteria meníngea. De cada una de estas, ramas separadas irrigaron la dura en donde una fina red de vasos cubrió el hueso. No se encontraron vasos mayores en el tejido blando supracalvario. Se encontraron numerosos vasos dentro del periostio y la dura entrando en las placas corticales. Las secciones descalcificadas de los huesos parietales revelaron una placa cortical interna y externa envolviendo un espacio diploico conteniendo trabéculas óseas, tejido medular y grandes sinusoides. Frecuentemente se encontraron conexiones huecas en las placas corticales internas y externas tanto en los especimenes sin tratar como en los tratados con GBA. Estas conexiones contenían tejido medular que se extendió hasta el periostio y la dura. Las medidas morfogenéticas revelaron proporciones similares de áreas corticales trabeculares y medulares en los huesos derecho e izquierdo no tratados. El área de la placa cortical externa fue significativamente mayor que el área de placa cortical interna. La densidad ósea fue similar en el lado derecho e izquierdo no tratados y en los especimenes tratados con GBA, así como la frecuencia y la anchura de las conexiones huecas a lo largo de las placas óseas corticales. Conclusiones:,La simetría entre los huesos parietales izquierdos y derechos concernientes a la topografía vascular y los parámetros histomorfométricos valorados fue alta. Las conexiones huecas en las placas corticales se encontraron con frecuencia. Se sugiere que el uso bilateral de huesos parietales es fiable como modelo experimental GBA respecto al suministro de sangre y calidad ósea. [source] |