Continuum formalism for modeling growing networks with deletion of nodes

We present a continuum formalism for modeling growing random networks under addition and deletion of nodes based on a differential mass balance equation. As examples of its applicability, we obtain new results on the degree distribution for growing networks with a uniform attachment and deletion of nodes, and complete some recent results on growing networks with preferential attachment and uniform removal

Adaptations of two specialist herbivores to movement on the hairy leaf surface of their host, Solanum guaraniticum Hassl (Solanaceae)

Plant trichomes can difficult the attachment and movement of small insects. Here, we examine the hypothesis that the success on the use of densely haired hosts by two cassidine species is determined by differential morphology and behavior. Larvae of Gratiana graminea (Klug, 1829) and Gratiana conformis (Boheman, 1854) move on the leaf surface of their host, Solanum guaraniticum Hassl by anchoring their tarsungulus on the trichome rays or by inserting the tarsungulus tip directly into epidermis. This kind of movement is only possible due to a similar tarsungulus shape among the species. Tarsungulus growth pattern is also similar between species, being relatively small on the posterior aperture, matching the diameter of the host plant trichome rays. The tarsungulus shape associated with differences on ontogenetic growth and attachment pattern allow these two Cassidinae larvae to efficiently move on the pubescent leaf surface of their host.

A collagen-poly(lactic acid-co-ɛ-caprolactone) hybrid scaffold for bladder tissue regeneration.

Scaffold materials should favor cell attachment and proliferation, and provide designable 3D structures with appropriate mechanical strength. Collagen matrices have proven to be beneficial scaffolds for tissue regeneration. However, apart from small intestinal submucosa, they offer a limited mechanical strength even if crosslinking can enhance their mechanical properties. A more cell-friendly way to increase material strength is to combine synthetic polymer meshes with plastic compressed collagen gels. This work describes the potential of plastic compressed collagen-poly(lactic acid-co-ɛ-caprolactone) (PLAC) hybrids as scaffolds for bladder tissue regeneration. Human bladder smooth muscle and urothelial cells were cultured on and inside collagen-PLAC hybrids in vitro. Scaffolds were analyzed by electron microscopy, histology, immunohistochemistry, and AlamarBlue assay. Both cell types proliferated in and on the hybrid, forming dense cell layers on top after two weeks. Furthermore, hybrids were implanted subcutaneously in the backs of nude mice. Host cell infiltration, scaffold degradation, and the presence of the seeded bladder cells were analyzed. Hybrids showed a lower inflammatory reaction in vivo than PLAC meshes alone, and first signs of polymer degradation were visible at six months. Collagen-PLAC hybrids have potential for bladder tissue regeneration, as they show efficient cell seeding, proliferation, and good mechanical properties.

The αVβ3/αVβ5 integrin inhibitor cilengitide augments tumor response to melphalan isolated limb perfusion in a sarcoma model.

Isolated limb perfusion (ILP) with melphalan and tumor necrosis factor (TNF)-α is used to treat bulky, locally advanced melanoma and sarcoma. However, TNF toxicity suggests a need for better-tolerated drugs. Cilengitide (EMD 121974), a novel cyclic inhibitor of alpha-V integrins, has both anti-angiogenic and direct anti-tumor effects and is a possible alternative to TNF in ILP. In this study, rats bearing a hind limb soft tissue sarcoma underwent ILP using different combinations of melphalan, TNF and cilengitide in the perfusate. Further groups had intra-peritoneal (i.p.) injections of cilengitide or saline 2 hr before and 3 hr after ILP. A 77% response rate (RR) was seen in animals treated i.p. with cilengitide and perfused with melphalan plus cilengitide. The RR was 85% in animals treated i.p. with cilengitide and ILP using melphalan plus both TNF and cilengitide. Both RRs were significantly greater than those seen with melphalan or cilengitide alone. Histopathology showed that high RRs were accompanied by disruption of tumor vascular endothelium and tumor necrosis. Compared with ILP using melphalan alone, the addition of cilengitide resulted in a three to sevenfold increase in melphalan concentration in tumor but not in muscle in the perfused limb. Supportive in vitro studies indicate that cilengitide both inhibits tumor cell attachment and increases endothelial permeability. Since cilengitide has low toxicity, these data suggest the agent is a good alternative to TNF in the ILP setting.

Worlds of working poverty : Cross-national variation in the mechanisms that lead to poverty among workers

The objective of this paper is to distinguish between different types of working poverty, on the basis of the mechanisms that produce it. Whereas the poverty literature identifies a myriad of risk factors and of categories of disadvantaged workers, we focus on three immediate causes of working poverty, namely low wage rate, weak labour force attachment, and high needs, the latter mainly due to the presence of children (and sometimes to the increase in needs caused by a divorce). These three mechanisms are the channels through which macroeconomic, demographic and policy factors have a direct bearing on working households. The main assumption tested here is that welfare regimes strongly influence the relative weight of these three mechanisms in producing working poverty, and, hence, the composition of the working-poor population. Our figures confirm this hypothesis and show that low-wage employment is a key factor, but, by far, not the only one and that family policies broadly understood play a decisive role, as well as patterns of labour market participation and integration.

Parents - child role reversal in trilogue play: case studies of trajectories from pregnancy to toddlerhood

Role reversal, whereby a child attempts to meet her parent's adult needs for parenting, intimacy, or companionship, has been identified as a risk factor for developmental disturbances. It has been defined from diverse perspectives as a child attachment strategy, a parent - toddler relational disturbance, and a boundary disturbance between parents and child. The recently discovered infant's triangular capacity, namely the sharing of her attention and affects with both parents, allows one to analyse the infant's contribution to early family dynamics. Role reversal was detected in 4 out of 45 father - mother - infant interactions observed in trilogue play from pregnancy to toddlerhood. The developmental trajectories towards role reversal are explored by means of case analyses. Results are compared with cases of problematic triangulation encountered in the same sample. In role reversal, family interactions are rigidly organized around a "two against one" coalition, whereby the normative hierarchy between parents and child is reversed. The child's triangular capacity is overactivated, controlling the tension between her parents by provocation - animation strategies

Molecular characterization of the processing of arenavirus envelope glycoprotein precursors by subtilisin kexin isozyme-1/site-1 protease.

A crucial step in the life cycle of arenaviruses is the biosynthesis of the mature fusion-active viral envelope glycoprotein (GP) that is essential for virus-host cell attachment and entry. The maturation of the arenavirus GP precursor (GPC) critically depends on proteolytic processing by the cellular proprotein convertase (PC) subtilisin kexin isozyme-1 (SKI-1)/site-1 protease (S1P). Here we undertook a molecular characterization of the SKI-1/S1P processing of the GPCs of the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) and the pathogenic Lassa virus (LASV). Previous studies showed that the GPC of LASV undergoes processing in the endoplasmic reticulum (ER)/cis-Golgi compartment, whereas the LCMV GPC is cleaved in a late Golgi compartment. Herein we confirm these findings and provide evidence that the SKI-1/S1P recognition site RRLL, present in the SKI-1/S1P prodomain and LASV GPC, but not in the LCMV GPC, is crucial for the processing of the LASV GPC in the ER/cis-Golgi compartment. Our structure-function analysis revealed that the cleavage of arenavirus GPCs, but not cellular substrates, critically depends on the autoprocessing of SKI-1/S1P, suggesting differences in the processing of cellular and viral substrates. Deletion mutagenesis showed that the transmembrane and intracellular domains of SKI-1/S1P are dispensable for arenavirus GPC processing. The expression of a soluble form of the protease in SKI-I/S1P-deficient cells resulted in the efficient processing of arenavirus GPCs and rescued productive virus infection. However, exogenous soluble SKI-1/S1P was unable to process LCMV and LASV GPCs displayed at the surface of SKI-I/S1P-deficient cells, indicating that GPC processing occurs in an intracellular compartment. In sum, our study reveals important differences in the SKI-1/S1P processing of viral and cellular substrates.

Role of DC-SIGN in Lassa virus entry into human dendritic cells.

The arenavirus Lassa virus (LASV) causes a severe hemorrhagic fever with high mortality in humans. Antigen-presenting cells, in particular dendritic cells (DCs), are early and preferred targets of LASV, and their productive infection contributes to the virus-induced immunosuppression observed in fatal disease. Here, we characterized the role of the C-type lectin DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN) in LASV entry into primary human DCs using a chimera of the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) expressing the LASV glycoprotein (rLCMV-LASVGP). We found that differentiation of human primary monocytes into DCs enhanced virus attachment and entry, concomitant with the upregulation of DC-SIGN. LASV and rLCMV-LASVGP bound to DC-SIGN via mannose sugars located on the N-terminal GP1 subunit of LASVGP. We provide evidence that DC-SIGN serves as an attachment factor for rLCMV-LASVGP in monocyte-derived immature dendritic cells (MDDC) and can accelerate the capture of free virus. However, in contrast to the phlebovirus Uukuniemi virus (UUKV), which uses DC-SIGN as an authentic entry receptor, productive infection with rLCMV-LASVGP was less dependent on DC-SIGN. In contrast to the DC-SIGN-mediated cell entry of UUKV, entry of rLCMV-LASVGP in MDDC was remarkably slow and depended on actin, indicating the use of different endocytotic pathways. In sum, our data reveal that DC-SIGN can facilitate cell entry of LASV in human MDDC but that its role seems distinct from the function as an authentic entry receptor reported for phleboviruses.

Targeting the proteolytic processing of the viral glycoprotein precursor is a promising novel antiviral strategy against arenaviruses.

A crucial step in the arenavirus life cycle is the biosynthesis of the viral envelope glycoprotein (GP) responsible for virus attachment and entry. Processing of the GP precursor (GPC) by the cellular proprotein convertase site 1 protease (S1P), also known as subtilisin-kexin-isozyme 1 (SKI-1), is crucial for cell-to-cell propagation of infection and production of infectious virus. Here, we sought to evaluate arenavirus GPC processing by S1P as a target for antiviral therapy using a recently developed peptide-based S1P inhibitor, decanoyl (dec)-RRLL-chloromethylketone (CMK), and the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV). To control for off-target effects of dec-RRLL-CMK, we employed arenavirus reverse genetics to introduce a furin recognition site into the GPC of LCMV. The rescued mutant virus grew to normal titers, and the processing of its GPC critically depended on cellular furin, but not S1P. Treatment with the S1P inhibitor dec-RRLL-CMK resulted in specific blocking of viral spread and virus production of LCMV. Combination of the protease inhibitor with ribavirin, currently used clinically for treatment of human arenavirus infections, resulted in additive drug effects. In cells deficient in S1P, the furin-dependent LCMV variant established persistent infection, whereas wild-type LCMV underwent extinction without the emergence of S1P-independent escape variants. Together, the potent antiviral activity of an inhibitor of S1P-dependent GPC cleavage, the additive antiviral effect with ribavirin, and the low probability of emergence of S1P-independent viral escape variants make S1P-mediated GPC processing by peptide-derived inhibitors a promising strategy for the development of novel antiarenaviral drugs.

The conditions for the reproduction of the SAGUAPAC water cooperative in the city of Santa Cruz de la Sierra, Bolivia : discourse analysis

The SAGUAPAC cooperative in the city of Santa Cruz de la Sierra (Eastern Bolivia) is regularly presented as an example of cooperative successes regarding water supply and sanitation. Its efficiency, both economic and technical, is widely considered as the main reason for its attractiveness. However, without denying its importance, we show, through a discourse analysis from and about SAGUAPAC in local media, that moral and non-instrumental factors are crucial in the reproduction of the cooperative. These factors create attachment and affection toward the cooperative, through a storytelling using a four-dimensional rhetoric (mythification, identification, emotionalisation and personification). This storytelling technique, internalized in the local media discourse and materializing the so-called new spirit of capitalism, exploits the affects and instrumentalisation of local myths and legends, as well as the 'camba' ethnic identity. In that, it tends to retain SAGUAPAC members and to canvass new ones, by providing them with recognition in their quality of local community members. However, the mobilisation of social norms and power hierarchies might end up reinforcing the social exclusion of Andean non-camba immigrants, inspite of an a priori inclusive and democratic organisation.

Merimies on erimies? Organisaatiositoutuminen suomalaisessa risteilyvarustamossa. Case: Kristina Cruises Oy

Tutkimuksen tavoitteena on selvittää, miten organisaatioon sitoutuminen moniulotteisena käsitteenä ymmärretään yrityksen johtoryhmässä ja avainesimiesten kesken, kun työpaikkana on risteilyvarustamo ja -laiva. Tutkimuksen empiirisen aineiston muodostaa viisi haastattelua laivan palveluosastoilta sekä yrityksen johtoryhmän haastattelut. Teoriaosuudessa on keskitytty kuvailemaan sitoutumiseen vaikuttavia tekijöitä ottaen huomioon kohdeorganisaation toimintaympäristö. Tässä tutkimuksessa organisaatiositoutuminen ymmärretään yksilön henkilökohtaisten tarpeiden, tunnepitoisen kiinnittymisen ja työyhteisön vaikutuksen yhteenliittymänä. Tutkimus on laadullinen ja aineiston keräystapana on käytetty pääasiallisesti teemahaastattelua. Aineistoa on täydennetty muutamalla avoimella sähköpostikyselyllä. Analysointi tapahtui teemoittelun avulla, josta johtopäätöksiin edettiin induktiivisesti. Tutkimustulosten perusteella voidaan todeta, että organisaatiositoutuminen kohdeyrityksessä on ymmärretty lähes samalla tavalla sekä johtoryhmän että esimiesten kesken. Huomioon otettavia aiheita sitouttamista silmällä pitäen ovat yrityksen arvojen ja tavoitteiden merkitys läpi koko sitoutumisprosessin.

Contaminação ambiental por compostos organoestânicos

The occurrence and the effects of organotin compounds (OTs) have been studied since a long time, due to their widespread use and deleterious effects. Some OTs are used as pesticides in crops, or as biocides in antifouling paints, applied in the ship hulls to avoid attachment and growth of tube worms, mussels and barnacles. However, "nontarget" organisms may be exposed, resulting in the poisoning of biological system, originating mutations and sentencing species to extinction. In this work we reported a revision study on the history of OTs and the techniques developed for its assessment and control.

Parents as Pain Killers in the Pain Management of Preterm Infants

Vanhemmat keskoslasten kivun lievittäjinä Tutkimuksen tarkoituksena oli kehittää uusi kivunlievitysmenetelmä, Vanhempien käsikapalo, keskoslasten kivunhoitoon vastasyntyneiden teho-osastolla. Vanhempien käsikapalon tehokkuutta verrattiin kahdessa satunnaistetussa kontrolloidussa crossover-tutkimusasetelmassa ei-lääkkeelliseen näyttöön perustuvaan hoitoon (P.O. glukoosiliuos), lääkkeelliseen menetelmään (I.V. oksikodoni) ja lumeeseen (P.O. vesi) tai kontrolli hoitoon kantapääpiston ja hengitysteiden imemisen aikana. Lisäksi mitattiin kivunhoidon lyhytaikaisia sivuvaikutuksia (hapetuksen- ja pulssinlasku) ja pidempiaikaisia vaikutuksia uneen. Tutkittujen lasten ikä oli 28 raskausviikkoa (n = 20) ja 28 1/7 (n = 20). Toimenpidekipua arvioitiin Premature Infant Pain Profile (PIPP) -kipumittarilla. Interventioiden jälkeen unen rakenne analysoitiin 13 tunnin polysomnografia-rekisteröinneistä. Viimeisessä vaiheessa haastateltiin äitejä (n = 23), jotka olivat käyttäneet vanhempien käsikapaloa 2–4 viikkoa vastasyntyneiden teho-osastolla, strukturoidulla the Clinical Interview for Parents of High-Risk Infants -haastattelulla, johon oli lisätty kysymyksiä lapsen kivunhoidosta. Kantapääpiston aikana PIPP–pisteet olivat merkitsevästi matalampia P.O. glukoosiliuoksella (ka 4,85 ± 1,73, p ≤ 0,001) ja vanhempien käsikapalolla (ka 5,20 ± 1,70, p = 0,004) verrattuna lumeeseen (ka 7,05 ± 2,16). Hengitysteiden imemisen yhteydessä PIPP–pisteet olivat matalampia P.O. glukoosiliuoksella (ka 11,05 ± 2,31, p = 0,014) ja vanhempien käsikapalolla (ka 11,25 ± 2,47, p = 0,034) verrattuna lumeeseen (ka 12,40 ± 2,06). Oksikodonin teho oli verrattavissa lumeeseen kummankin toimenpiteen aikana. P.O. glukoosiliuoksen (21,3 %) ja lumeen (12,5 %) annosteluun liittyi merkittävästi enemmän lyhytaikaisia sivuvaikutuksia verrattuna oksikodoniin (5 %) tai vanhempien käsikapaloon (5 %). Oksikodoni muutti keskoslasten unen rakennetta vähentämällä merkittävästi aktiivisen unen määrää verrattuna muihin hoitoihin. Vanhemmat suhtautuivat positiivisesti käsikapalon käyttöön. Äitien osallistuminen kivunhoitoon voitiin jaotella kolmeen eri tyylin, jotka selittyivät äidin kiintymyksen tunteilla ja lapsen tehohoitoon liittyvällä stressillä. Vanhempien käsikapalo on suositeltavampi lyhyen toimenpidekivun lievittäjä kuin P.O. glukoosiliuos tai I.V. oksikodoni, kun tehokkuus, turvallisuus ja perhe otetaan huomioon.

Crystallization characteristics of bioactive glasses

Bioactive glasses are excellent candidates for implant materials, because they can form a chemical bond to bone or guide bone growth, depending on the glass composition. Some compositions have even shown soft tissue attachment and antimicrobial effects. So far, most clinical applications are based on monoliths, plates and particulates of different grain sizes. There is a growing interest in special products such as porous implants sintered from microspheres and fibers drawn from preforms or glass melts. The viscosity range at which these are formed coincides with the crystallization temperature range for most bioactive glasses, thus complicating the manufacturing process. In this work, the crystallization tendency and its kinetics for a series of glasses with their compositions within the range of bioactivity were investigated. The factors affecting crystallization and how it is related to composition were studied by means of thermal analysis and hot stage microscopy. The crystal compositions formed during isothermal and non-isothermal heat treatments were analyzed with SEM-EDXA and X-ray diffraction analysis. The temperatures at which sintering and fiber drawing can take place without interfering with crystallization were determined and glass compositions which are suitable for these purposes were established. The bioactivity of glass fibers and partly crystallized glass plates was studied by soaking them in simulated body fluid (SBF). The thickness of silica, calcium and phosphate rich reaction layers on the glass surface after soaking was used as an indication of the bioactivity. The results indicated that the crystallization tendencies of the experimental glasses are strongly dependent on composition. The main factor affecting the crystallization was found to be the alkali oxide content: the higher the alkali oxide content the lower the crystallization temperature. The primary crystalline phase formed at low temperatures in these glasses was sodium calcium silicate. The crystals were found to form through internal nucleation, leading to bulk crystallization. These glasses had high bioactivity in vitro. Even when partially crystalline, they formed typical reaction layers, indicating bioactivity. In fact, sodium calcium silicate crystals were shown to transform in vitro into hydroxyapatite during soaking. However, crystallization should be avoided because it was shown to retard dissolution, bioactivity reactions and complicate fiber drawing process. Glass compositions having low alkali oxide content showed formation of wollastonite crystals on the surface, at about 300°C above the glass transition temperature. The wide range between glass transition and crystallization allowed viscous flow sintering of these compositions. These glasses also withstood the thermal treatments required for fiber drawing processing. Precipitation of calcium and phosphate on fibers of these glasses in SBF suggested that they were osteoconductive. Glasses showing bioactivity crystallize easily, making their hot working challenging. Undesired crystallization can be avoided by choosing suitable compositions and heat treatment parameters, allowing desired product forms to be attained. Small changes in the oxide composition of the glass can have large effects and therefore a thorough understanding of glass crystallization behavior is a necessity for a successful outcome, when designing and manufacturing implants containing bioactive glasses.

Unidirectional fiber-reinforced composite as an oral implant abutment material: Experimental studies of E-glass fiber/BisGMA-TEGDMA polymer in vitro

Fiber-reinforced composites (FRCs) are a new group of non-metallic biomaterials showing a growing popularity in many dental and medical applications. As an oral implant material, FRC is biocompatible in bone tissue environment. Soft tissue integration to FRC polymer material is unclear. This series of in vitro studies aimed at evaluating unidirectional E-glass FRC polymer in terms of mechanical, chemical, and biological properties in an attempt to develop a new non-metallic oral implant abutment alternative. Two different types of substrates were investigated: (a) Plain polymer (BisGMA 50%–TEGDMA 50%) and (b) Unidirectional FRC. The mechanical behavior of high fiber-density FRCs was assessed using a three-point bending test. Surface characterization was performed using scanning electron and spinning disk confocal microscopes. The surface wettability/energy was determined using sessile drop method. The blood response, including blood-clotting ability and platelet morphology was evaluated. Human gingival fibroblast cell responses - adhesion kinetics, adhesion strength, and proliferation activity - were studied in cell culture environment using routine test conditions. A novel tissue culture method was developed and used to evaluate porcine gingival tissue graft attachment and growth on the experimental composite implants. The analysis of the mechanical properties showed that there is a direct proportionality in the relationship between E-glass fiber volume fraction and toughness, modulus of elasticity, and load bearing capacity; however, flexural strength did not show significant improvement when high fiber-density FRC is used. FRCs showed moderate hydrophilic properties owing to the presence of exposed glass fibers on the polymer surface. Blood-clotting time was shorter on FRC substrates than on plain polymer. The FRC substrates also showed higher platelet activation state than plain polymer substrates. Fibroblast cell adhesion strength and proliferation rate were highly pronounced on FRCs. A tissue culture study revealed that gingival epithelium and connective tissue established an immediate close contact with both plain polymer and FRC implants. However, FRC seemed to guide epithelial migration outwards from the tissue/implant interface. Due to the anisotropic and hydrophilic nature of FRC, it can be concluded that this material enhances biological events related with soft tissue integration on oral implant surface.