Biomechanics of the movable pretarsal adhesive organ in ants and bees

Hymenoptera attach to smooth surfaces with a flexible pad, the arolium, between the claws. Here we investigate its movement in Asian weaver ants (Oecophylla smaragdina) and honeybees (Apis mellifera).  When ants run upside down on a smooth surface, the arolium is unfolded and folded back with each step. Its extension is strictly coupled with the retraction of the claws. Experimental pull on the claw-flexor tendon revealed that the claw-flexor muscle not only retracts the claws, but also moves the arolium. The elicited arolium movement comprises (i) about a 90° rotation (extension) mediated by the interaction of the two rigid pretarsal sclerites arcus and manubrium and (ii) a lateral expansion and increase in volume. In severed legs of O. smaragdina ants, an increase in hemolymph pressure of 15 kPa was sufficient to inflate the arolium to its full size. Apart from being actively extended, an arolium in contact also can unfold passively when the leg is subject to a pull toward the body.  We propose a combined mechanical–hydraulic model for arolium movement: (i) the arolium is engaged by the action of the unguitractor, which mechanically extends the arolium; (ii) compression of the arolium gland reservoir pumps liquid into the arolium; (iii) arolia partly in contact with the surface are unfolded passively when the legs are pulled toward the body; and (iv) the arolium deflates and moves back to its default position by elastic recoil of the cuticle.

Benzothiadiazole-Mediated Induced Resistance to Fusarium oxysporum f. sp. radicis-lycopersici in Tomato1

Benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), a synthetic chemical, was applied as a foliar spray to tomato (Lycopersicon esculentum) plants and evaluated for its potential to confer increased resistance against the soil-borne pathogen Fusarium oxysporum f. sp. radicis-lycopersici (FORL). In nontreated tomato plants all root tissues were massively colonized by FORL hyphae. Pathogen ingress toward the vascular stele was accompanied by severe host cell alterations, including cell wall breakdown. In BTH-treated plants striking differences in the rate and extent of fungal colonization were observed. Pathogen growth was restricted to the epidermis and the outer cortex, and fungal ingress was apparently halted by the formation of callose-enriched wall appositions at sites of fungal penetration. In addition, aggregated deposits, which frequently established close contact with the invading hyphae, accumulated in densely colonized epidermal cells and filled most intercellular spaces. Upon incubation of sections with gold-complexed laccase for localization of phenolic-like compounds, a slight deposition of gold particles was observed over both the host cell walls and the wall appositions. Labeling was also detected over the walls of fungal cells showing signs of obvious alteration ranging from cytoplasm disorganization to protoplasm retraction. We provide evidence that foliar applications of BTH sensitize susceptible tomato plants to react more rapidly and more efficiently to FORL attack through the formation of protective layers at sites of potential fungal entry.

Localization of the central rhythm generator involved in spontaneous consummatory licking in rats: functional ablation and electrical brain stimulation studies.

Localization of the central rhythm generator (CRG) of spontaneous consummatory licking was studied in freely moving rats by microinjection of tetrodotoxin (TTX) into the pontine reticular formation. Maximum suppression of spontaneous water consumption was elicited by TTX (1 ng) blockade of the oral part of the nucleus reticularis gigantocellularis (NRG), whereas TTX injections into more caudal or rostral locations caused significantly weaker disruption of drinking. To verify the assumption that TTX blocked the proper CRG of licking rather than some relay in its output, spontaneously drinking thirsty rats were intracranially stimulated via electrodes chronically implanted into the oral part of the NRG. Lick-synchronized stimulation (a 100-ms train of 0.1-ms-wide rectangular pulses at 100 Hz and 25-150 microA) applied during continuous licking (after eight regular consecutive licks) caused a phase shift of licks emitted after stimulus delivery. The results suggest that the stimulation has reset the CRG of licking without changing its frequency. The reset-inducing threshold current was lowest during the tongue retraction and highest during the tongue protrusion period of the lick cycle. It is concluded that the CRG of licking is located in the oral part of NRG.

Cleavage of actin by interleukin 1 beta-converting enzyme to reverse DNase I inhibition.

Three of the predominant features of apoptosis are internucleosomal DNA fragmentation, plasma membrane bleb formation, and retraction of cell processes. We demonstrate that actin is a substrate for the proapoptotic cysteine protease interleukin 1beta-converting enzyme. Actin cleaved by interleukin 1beta-converting enzyme can neither inhibit DNase I nor polymerize to its filamentous form as effectively as intact actin. These findings suggest a mechanism for the coordination of the proteolytic, endonucleolytic, and morphogenetic aspects of apoptosis.

Clinical Characterization of Asymptomatic or Minimally Symptomatic Young Patients Showing Signs Compatible With Dry Eye: A Pilot Study

Purpose: To evaluate and characterize the clinical profile of young asymptomatic or minimally symptomatic patients without diagnosis of dry eye but showing signs compatible with dry eye syndrome (DES). Methods: Prospective study including a total of 50 consecutive subjects with ages ranging from 18 to 40 years that were identified as asymptomatic or minimally symptomatic by means of the Ocular Surface Disease Index (OSDI) (score of <22). In all patients, a complete battery of tests for the diagnosis of DES was performed including the evaluation of the tear film break-up time (TFBUT), the level of corneal and conjunctival staining, and the eyelid and Meibomian morphology. Results: The OSDI score was significantly higher in women than in men (median: 12.5 vs. 5.3, P=0.01). Low grades of ocular surface staining, dysfunction of Meibomian gland expression, and alteration of quality of Meibomian secretions were observed in 56%, 58%, and 84% of eyes, respectively. More eyes with some dysfunction of Meibomian gland expressibility had a TFBUT less than 5 sec (P=0.033). A statistically significant difference in the OSDI score was found between patients with and without systemic allergies (P=0.036) and between male and female (P=0.01). Likewise, the OSDI score was significantly higher in those women wearing contact lenses compared with those not wearing them (P=0.012). Conclusions: Asymptomatic or minimally symptomatic young subjects may present low grades of clinical signs compatible with DES, with a trend to more symptomatology in women and allergic patients. These outcomes should be confirmed in future studies with larger samples.

Lesão hiperemiada do bordo palpebral

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

O controlo interno e a implementação de auditorias online no Safex em contexto de e-governance: Tecnologias, desafios e oportunidades

O presente Relatório Detalhado de Atividade Profissional é apresentado no âmbito da obtenção do Grau de Mestre dos Oficiais do Exército licenciados pré-Bolonha pela Academia Militar na Área específica de Administração Militar. A sua redação e estruturação tem por base o definido na NEP 520 e NEP 517/1ª da AM, para esta tipologia de trabalhos, tendo o autor, optado por desenvolver um tema no âmbito da sua atividade profissional, considerado como pioneiro e inovador. O Tenente-Coronel de Administração Militar do Exército Português, Luís Miguel Gonçalves, nasceu a 25 de Novembro de 1971. Do seu percurso académico e formativo, consta frequência pré-Universitária, em estabelecimento militar de ensino, no Instituto Militar dos Pupilos do Exército, na área de Contabilidade e Administração; a Licenciatura em Ciências Militares, na especialidade de Administração Militar, pela Academia Militar, em 1995, com a Classificação final de 13,58 valores; o tirocínio para Oficiais de Administração Militar, com a nota final de 15,38 valores; o Curso de Operações Irregulares, tendo obtido a classificação de 17,67 valores; o Curso de Promoção a Capitão, com 16,63 valores; e o Curso de Promoção a Oficial Superior do Instituto de Altos Estudos Militares, com a classificação final de 14,50 valores. No âmbito da formação de pós-graduação, tem averbado créditos no módulo de Metodologia de Investigação Cientifica, pela Academia Militar, no Ano Letivo 2013/14, com a classificação final de 16,00 valores. Para além destes, o Environmental Course For Portugal – NATO School/ SHAPE; formação em Gestão de Projetos/ Exército - Microsoft Enterprise Project Management; o Curso de Formação Pedagógica Inicial de Formadores do Instituto de Emprego e Formação Profissional, com Homologação das Competências Pedagógicas; e vários certificados de formações no âmbito da Contabilidade, Administração, Finanças Públicas e Auditorias Financeiras, atribuídas pela Direção de Finanças do Exército e pelo Instituto de Gestão e Administração Pública do Porto. Ao longo dos 25 anos de serviço prestado ao Exército Português, como Oficial de Administração Militar, desempenhou diversos cargos e funções de Comando e Chefia, em várias UEO, nas áreas setoriais e funcionais, da formação, da instrução, da componente operacional, da logística, do pessoal, das finanças públicas, das inspeções e auditorias, da gestão e da Administração Militar. Atualmente o Tenente-Coronel Miguel Gonçalves, desempenha as Funções de Comandante de Batalhão na Escola dos Serviços. Para além dos cargos e funções averbadas no seu Curriculum Vitae detalhado, constituiu em 1996 o Núcleo Logístico de Projeção, Implantação, Acompanhamento e Ajuda Técnica no âmbito do emprego dos meios táticos e operacionais da Área de Responsabilidade FND/ IFOR na Bósnia-Herzegovina (Jugoslávia). Tem publicado na Revista da Administração Militar, vários artigos no âmbito da logística operacional, na função de combate Apoio de Serviços. Na área da formação, foi orientador e supervisor de vários trabalhos, individuais e de grupo aos cursos de promoção a capitão; e constitui-se como elemento primariamente responsável pelo planeamento e implementação dos primeiros cursos no Exército, com formação certificado pela Agência Nacional para a Qualificação e Ensino Profissional, I.P., do Sistema Nacional de Qualificações, certificação inserida no Catálogo Nacional de Qualificações. Na área Inspetiva, integrou várias equipas de Inspeção-Geral do Exército, como inspetor responsável pelas áreas de Logística e Finanças, bem como as de Inspetor, para a área dos recursos humanos – Despesas com Pessoal, nas equipas de inspeção do Comando do Pessoal do Exército. No desempenho das funções de Auditor Financeiro do Centro de Finanças do Comando do Pessoal, realizou diversas auditorias financeiras às UEO do Comando do Pessoal, na sua dependência, tendo desenvolvido e implementado um sistema pioneiro e inovador de monitorização e controlo interno, de auditorias “Online” com análise e reporte mensal, às contas das UEO do Comando do Pessoal, tendo em vista a validação das Demonstrações Financeiras para a Conta de Gerência Anual do Exército. A escolha do tema, “O Controlo Interno e a implementação de Auditorias Online no SAFEx em contexto de e-Governance: Tecnologias, desafios e oportunidades” surge na sequência da implementação destes procedimentos pelo autor, numa altura em que o Exército entrava em operativo com o Sistema Integrado de Gestão (SIG/DN), tendo sido à data reconhecido publicamente pelo TGEN Comandante do Pessoal do Exército, como sendo um procedimento inovador, com notáveis vantagens para a eficiência e eficácia do sistema administrativo-financeiro do Comando do Pessoal e consequentemente do Exército.

Effects of the fibers distribution in the human eardrum: A biomechanical study

The eardrum separates the external ear from the middle ear and it is responsible to convert the acoustical energy into mechanical energy. It is divided by pars tensa and pars flaccida. The aim of this work is to analyze the susceptibility of the four quadrants of the pars tensa under negative pressure, to different lamina propria fibers distribution. The development of associated ear pathology, in particular the formation of retraction pockets, is also evaluated. To analyze these effects, a computational biomechanical model of the tympano-ossicular chain was constructed using computerized tomography images and based on the finite element method. Three fibers distributions in the eardrum middle layer were compared: case 1 (eardrum with a circular band of fibers surrounding all quadrants equally), case 2 (eardrum with a circular band of fibers that decreases in thickness in posterior quadrants), case 3 (eardrum without circular fibers in the posterior/superior quadrant). A static analysis was performed by applying approximately 3000Pa in the eardrum. The pars tensa of the eardrum was divided in four quadrants and the displacement of a central point of each quadrant analyzed. The largest displacements of the eardrum were obtained for the eardrum without circular fibers in the posterior/superior quadrant.

Effects of the fibers distribution in the human eardrum: A biomechanical study

The eardrum separates the external ear from the middle ear and it is responsible to convert the acoustical energy into mechanical energy. It is divided by pars tensa and pars flaccida. The aim of this work is to analyze the susceptibility of the four quadrants of the pars tensa under negative pressure, to different lamina propria fibers distribution. The development of associated ear pathology, in particular the formation of retraction pockets, is also evaluated. To analyze these effects, a computational biomechanical model of the tympano-ossicular chain was constructed using computerized tomography images and based on the finite element method. Three fibers distributions in the eardrum middle layer were compared: case 1 (eardrum with a circular band of fibers surrounding all quadrants equally), case 2 (eardrum with a circular band of fibers that decreases in thickness in posterior quadrants), case 3 (eardrum without circular fibers in the posterior/superior quadrant). A static analysis was performed by applying approximately 3000Pa in the eardrum. The pars tensa of the eardrum was divided in four quadrants and the displacement of a central point of each quadrant analyzed. The largest displacements of the eardrum were obtained for the eardrum without circular fibers in the posterior/superior quadrant.

Activities of fenbendazole in comparison with albendazole against Echinococcus multilocularis metacestodes in vitro and in a murine infection model.

The current chemotherapeutic treatment of alveolar echinococcosis (AE) in humans is based on albendazole and/or mebendazole. However, the costs of treatment, life-long consumption of drugs, parasitostatic rather than parasiticidal activity of chemotherapy, and high recurrence rates after treatment interruption warrant more efficient treatment options. Experimental treatment of mice infected with Echinococcus multilocularis metacestodes with fenbendazole revealed similar efficacy to albendazole. Inspection of parasite tissue from infected and benzimidazole-treated mice by transmission electron microscopy (TEM) demonstrated drug-induced alterations within the germinal layer of the parasites, and most notably an almost complete absence of microtriches. On the other hand, upon in vitro exposure of metacestodes to benzimidazoles, no phosphoglucose isomerase activity could be detected in medium supernatants during treatment with any of these drugs, indicating that in vitro treatment did not severely affect the viability of metacestode tissue. Corresponding TEM analysis also revealed a dramatic shortening/retraction of microtriches as a hallmark of benzimidazole action, and as a consequence separation of the acellular laminated layer from the cellular germinal layer. Since TEM did not reveal any microtubule-based structures within Echinococcus microtriches, this effect cannot be explained by the previously described mechanism of action of benzimidazoles targeting β-tubulin, thus benzimidazoles must interact with additional targets that have not been yet identified. In addition, these results indicate the potential usefulness of fenbendazole for the chemotherapy of AE.

Blephoroplasty

Pastel, crayon, and watercolor on video paper; Dr. Reed O. Dingman, University of Michigan Department of Plastic Surgery

Facilitating Locking Pin Alignment in Transtibial Amputees via Auto-Retracting Tethered Pin

Thesis (Master's)--University of Washington, 2016-06

Dynamics of motor nerve terminal remodeling unveiled using SNARE-cleaving botulinum toxins: the extent and duration are dictated by the sites of SNAP-25 truncation

Nerve sprouts emerge from motor nerve terminals following blockade of exo-endocytosis for more than 3 days by botulinum neurotoxin (BoNT), and form functional synapses, albeit temporary. Upon restoration of synaptic activity to the parent terminal 7 and 90 days after exposure to BoNT/F or A respectively, a concomitant retraction of the outgrowths was observed. BoNT/E caused short-term neuroparalysis, and dramatically accelerated the recovery of BoNT/A-paralyzed muscle by further truncation of SNAP-25 and its replenishment with functional full-length SNARE. The removal of 9 C-terminal residues from SNAP-25 by BoNT/A leads to persistence of the inhibitory product due to the formation of a nonproductive SNARE complex(es) at release sites, whereas deletion of a further 17 amino acids permits replenishment and a speedy recovery. (C) 2003 Elsevier Science (USA). All rights reserved.

Repelling class discrimination: ephrin-A5 binds to and activates EphB2 receptor signaling

The interactions between Eph receptor tyrosine kinases and their ephrin ligands regulate cell migration and axon pathfinding. The EphA receptors are generally thought to become activated by ephrin-A ligands, whereas the EphB receptors interact with ephrin-B ligands. Here we show that two of the most widely studied of these molecules, EphB2 and ephrin-A5, which have never been described to interact with each other, do in fact bind one another with high affinity. Exposure of EphB2-expressing cells to ephrin-A5 leads to receptor clustering, autophosphorylation and initiation of downstream signaling. Ephrin-A5 induces EphB2-mediated growth cone collapse and neurite retraction in a model system. We further show, using X-ray crystallography, that the ephrin-A5-EphB2 complex is a heterodimer and is architecturally distinct from the tetrameric EphB2-ephrin-B2 structure. The structural data reveal the molecular basis for EphB2-ephrin-A5 signaling and provide a framework for understanding the complexities of functional interactions and crosstalk between A- and B-subclass Eph receptors and ephrins.

Characterization of a complex chemosensory signal transduction system which controls twitching motility in Pseudomonas aeruginosa

Virulence of the opportunistic pathogen Pseudomonas aeruginosa involves the coordinate expression of a wide range of virulence factors including type IV pili which are required for colonization of host tissues and are associated with a form of surface translocation termed twitching motility. Twitching motility in P. aeruginosa is controlled by a complex signal transduction pathway which shares many modules in common with chemosensory systems controlling flagella rotation in bacteria and which is composed, in part, of the previously described proteins PilG, PilH, PilI, PilJ and PilK. Here we describe another three components of this pathway: ChpA, ChpB and ChpC, as well as two downstream genes, ChpD and ChpE, which may also be involved. The central component of the pathway, ChpA, possesses nine potential sites of phosphorylation: six histidine-containing phosphotransfer (HPt) domains, two novel serine- and threonine-containing phosphotransfer (SPt, TPt) domains and a CheY-like receiver domain at its C-terminus, and as such represents one of the most complex signalling proteins yet described in nature. We show that the Chp chemosensory system controls twitching motility and type IV pili biogenesis through control of pili assembly and/or retraction as well as expression of the pilin subunit gene pilA. The Chp system is also required for full virulence in a mouse model of acute pneumonia.