Mechanical strain induces growth of vascular smooth muscle cells via autocrine action of PDGF.

The effect of cyclic mechanical strain on growth of neonatal rat vascular smooth muscle (VSM) cells were examined. Cells were grown on silicone elastomer plates subjected to cyclic strain (60 cycle/min) by application of a vacuum under the plates. A 48 h exposure to mechanical strain increased the basal rate of thymidine incorporation by threefold and increased cell number by 40% compared with cells grown on stationary rubber plates. Strain also increased the rate of thymidine incorporation in response to alpha-thrombin (from 15- to 33-fold), but not to PDGF. As determined by thymidine autoradiography, strain alone induced a fourfold increase in labeled nuclei at the periphery of dishes, where strain is maximal, and a 2-3-fold increase at the center of dishes. Strain appeared to induce the production of an autocrine growth factor(s), since conditioned medium from cells subjected to strain induced a fourfold increase in DNA synthesis in control cells. Western blots of medium conditioned on the cells subjected to strain indicate that the cells secrete both AA and BB forms of PDGF in response to strain. Northern blots of total cell RNA from cells exposed to strain for 24 h show increased steady-state level of mRNA for PDGF-A. Lastly, polyclonal antibodies to the AA form of PDGF reduced by 75% the mitogenic effect of strain and polyclonal antibodies to AB-PDGF reduced mitogenicity by 50%. Antibodies to bFGF did not significantly reduce the strain-induced thymidine incorporation. Thus, the mechanism of strain-induced growth appears to involve the intermediary action of secreted PDGF

Theoriebedingte Wörterbuchformprobleme und wörterbuchformbedingte Benutzerprobleme I. Ein Beitrag zur Wörterbuchkritik und zur Erweiterung der Theorie der Wörterbuchform

Der empirische Gegenstandsbereich der Wörterbuchforschung verändertsich u.a. dadurch, dass neue Wörterbücher erscheinen. Dabei ist ein Trend zu erkennen, dass zunehmend mehr neue Elemente der Wörterbuchform im Vorspann, im Wörterverzeichnis und im Nachspann auftreten. Die Wörterbuchform wird dadurch komplexer. Für die Theorie der Wörterbuchform ergeben sich dadurch theoriebedingte Wörterbuchformprobleme: Will die Theorie die neuen Entwicklungen berücksichtigen, muss sie erweitert werden und wird dadurch zunehmendkomplexer. Wird sie erweitert, erkennt man im Licht der Theorie die Stärken und Schwächen der neuen Formelemente; das führt zur Wörterbuchkritik. Besonders die Schwächen führen zu  wörterbuchformbedingten Benutzerproblemen. In diesem ersten Teil des Beitrags werden theoriebedingte Artikelformprobleme behandelt, die sich durch die Berücksichtigung eines bisher nicht untersuchten Artikeltyps ergeben, nämlich den Typ des komplexen Wörterbuchartikels, in dem zwei oder mehr formgleiche Wörter lexikographisch bearbeitet werden, die zu zwei oder mehr Wortklassen gehören. Die theoriebedingten  Artikelformprobleme bestehen darin, dass es keine Strukturkonzeptionfür Artikel dieses Typs, keine systematische Terminologie, keine Typologie und z.T. keine Darstellungsmittel und –methoden gibt. Die Probleme werden dadurch gelöst, dass die Theorie der Wörterbuchform um die fehlenden Elemente systematisch erweitert und die Heuristik ergänztwird

Relationship between the molecular composition, visible light absorption, and health-related properties of smoldering woodsmoke aerosols

Organic aerosols generated from the smoldering combustion of wood critically impact air quality and health for billions of people worldwide; yet, the links between the chemical components and the optical or biological effects of woodsmoke aerosol (WSA) are still poorly understood. In this work, an untargeted analysis of the molecular composition of smoldering WSA, generated in a controlled environment from nine types of heartwood fuels (African mahogany, birch, cherry, maple, pine, poplar, red oak, redwood, and walnut), identified several hundred compounds using gas chromatography mass spectrometry (GCMS) and nano-electrospray high-resolution mass spectrometry (HRMS) with tandem multistage mass spectrometry (MSn). The effects of WSA on cell toxicity as well as gene expression dependent on the aryl hydrocarbon receptor (AhR) and estrogen receptor (ER) were characterized with cellular assays, and the visible mass absorption coefficients (MACvis) of WSA were measured with ultraviolet-visible spectroscopy. The WSAs studied in this work have significant levels of biological and toxicological activity, with exposure levels in both an outdoor and indoor environment similar to or greater than those of other toxicants. A correlation between the HRMS molecular composition and aerosol properties found that phenolic compounds from the oxidative decomposition of lignin are the main drivers of aerosol effects, while the cellulose decomposition products play a secondary role; e.g., levoglucosan is anticorrelated with multiple effects. Polycyclic aromatic hydrocarbons (PAHs) are not expected to form at the combustion temperature in this work, nor were they observed above the detection limit; thus, biological and optical properties of the smoldering WSA are not attributed to PAHs. Syringyl compounds tend to correlate with cell toxicity, while the more conjugated molecules (including several compounds assigned to dimers) have higher AhR activity and MACvis. The negative correlation between cell toxicity and AhR activity suggests that the toxicity of smoldering WSA to cells is not mediated by the AhR. Both mass-normalized biological outcomes have a statistically significant dependence on the degree of combustion of the wood. In addition, our observations support the fact that the visible light absorption of WSA is at least partially due to charge transfer effects in aerosols, as previously suggested. Finally, MACvis has no correlation with toxicity or receptor signaling, suggesting that key chromophores in this work are not biologically active on the endpoints tested

Effect of Bone Marrow-derived Mesenchymal Stem Cells and Umbilical Cord Blood-CD34+ cells on Experimental Rat liver Fibrosis

Background and Objective: Liver disease is one of the major causes of death in many countries. Hence, the development of effective therapies for liver fibrosis is a major aim of medical research. So this study was designed to investigate the therapeutical role of mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) transplantation in the experimental rat liver fibrosis. Design and Method: Bone marrow-derived MSCs were isolated from femoral and tibial bones of male albino rats, then were grown and propagated in culture for 2 weeks and were characterized morphologically and by detection of CD29 by real time-PCR. Human umbilical cord blood cells were obtained after full-term caesarean delivery from healthy donors after written informed consent. Low-density mononuclear cells were separated over Ficoll- Paque (Gibco-Invitrogen, Grand Island, NY), and then CD34+ HSC was isolated using a magnetic cell sorter (MiniMACS; Miltenyi Biotec, Bergisch Gladbach, Germany). The cells were then infused intraperitoneally in rats that received CCl4 injection to induce liver fibrosis. Rats were divided into 4 groups: control, CCl4, CCl4 plus MSC, and CCl4 plus CD34+. Liver tissue was examined histopathologically for all groups. The expression of collagen I and metalloproteinase-2 genes as a marker of liver fibrosis was measured by real time RT- PCR. Results: The results of the present study showed that both MSCs and CD34+ have a significant antifibrotic effect as evidenced by the significant decrease in liver collagen gene expression as well as the decrease in MMP-2 (p < 0.05) compared to the CCl4 group

Fretting of CoCrMo and Ti6Al4V Alloys in Modular Prostheses

Implantation of a total hip replacements (THR) is an effective intervention in the management of arthritis. Modularity at the taper junction of THR was introduced in order to improve the ease with which the surgeon could modify the length of the taper section and the overall length of the replacement. Cobalt chromium (Co–28Cr–6Mo) and titanium (Ti–6Al–4V) alloys are the most commonly used materials for the device. This study investigates the fretting behaviour of both CoCr–CoCr and CoCr–Ti couplings and analyses their damage mechanisms. A reciprocating tribometer ball on plate fretting contact was instrumented with in situ electrochemistry to characterise the damage inflicted by tribocorrosion on the two couplings. Fretting displacements amplitudes of 10, 25 and 50 mm at an initial contact pressure of 1 GPa were assessed. The results reveal larger metallic volume loss from the CoCr–CoCr alloy compared to the CoCr–Ti alloy, and the open circuit potential indicates a depassivation of the protective oxide layer at displacement amplitudes .25 mm. In conclusion, the damage mechanisms of CoCr–CoCr and CoCr–Ti fretting contacts were identified to be wear and fatigue dominated mechanisms respectively

Two binary stars gravitational waves - homotopy perturbation method

Homotopy perturbation is one of the newest methods for numerical analysis of deferential equations. We have used for solving wave equation around a black hole. Our conclusions have this method far reaching consequences for comparison of theoritical physics and experimental physics.Comment: The manuscript considers the important problem of solve equation wave around a black hole. We have solved that by using Homotopy perturbation methods. Homotopy perturbation is one of the newest methods for numerical analysis of deferential equations. Our conclusions have far reaching consequences for comparison of theoritical physics and experimental physic

A Case-Control Study to Identify Community Venues Associated with Genetically-clustered, Multidrug-resistant Tuberculosis Disease in Lima, Peru

Background: The majority of tuberculosis transmission occurs in community settings. Our primary aim in this study was to assess the association between exposure to community venues and multidrug-resistant (MDR) tuberculosis. Our secondary aim was to describe the social networks of MDR tuberculosis cases and controls. / Methods: We recruited laboratory-confirmed MDR tuberculosis cases and community controls that were matched on age and sex. Whole-genome sequencing was used to identify genetically clustered cases. Venue tracing interviews (nonblinded) were conducted to enumerate community venues frequented by participants. Logistic regression was used to assess the association between MDR tuberculosis and person-time spent in community venues. A location-based social network was constructed, with respondents connected if they reported frequenting the same venue, and an exponential random graph model (ERGM) was fitted to model the network. / Results: We enrolled 59 cases and 65 controls. Participants reported 729 unique venues. The mean number of venues reported was similar in both groups (P = .92). Person-time in healthcare venues (adjusted odds ratio [aOR] = 1.67, P = .01), schools (aOR = 1.53, P < .01), and transportation venues (aOR = 1.25, P = .03) was associated with MDR tuberculosis. Healthcare venues, markets, cinemas, and transportation venues were commonly shared among clustered cases. The ERGM indicated significant community segregation between cases and controls. Case networks were more densely connected. / Conclusions: Exposure to healthcare venues, schools, and transportation venues was associated with MDR tuberculosis. Intervention across the segregated network of case venues may be necessary to effectively stem transmission

Nuisance

This essay sets out the law and the economic theory of nuisance. Nuisance law serves a regulatory function: it induces actors to choose the socially preferred level of an activity by imposing liability when the externalized costs of the activity are substantially greater than the externalized benefits or not reciprocal to other background external costs. Proximate cause doctrine plays a role in supplementing nuisance law

On All-loop Integrands of Scattering Amplitudes in Planar N=4 SYM

We study the relationship between the momentum twistor MHV vertex expansion of planar amplitudes in N=4 super-Yang-Mills and the all-loop generalization of the BCFW recursion relations. We demonstrate explicitly in several examples that the MHV vertex expressions for tree-level amplitudes and loop integrands satisfy the recursion relations. Furthermore, we introduce a rewriting of the MHV expansion in terms of sums over non-crossing partitions and show that this cyclically invariant formula satisfies the recursion relations for all numbers of legs and all loop orders.Comment: 34 pages, 17 figures; v2: Minor improvements to exposition and discussion, updated references, typos fixe

A complex pattern of post‐divergence expansion, contraction, introgression and asynchronous responses to Pleistocene climate changes in two Dipelta sister species from western China

The well-known vicariance and dispersal models dominate in understanding the allopatric pattern for related species and presume the simultaneous occurrence of speciation and biogeographic events. However, the formation of allopatry may postdate the species divergence. We examined this hypothesis using DNA sequence data from 3 chloroplast fragments and 5 nuclear loci of Dipelta floribunda and D. yunnanensis, two shrub species with the circum Sichuan Basin distribution, combining the climatic niche modeling approach. The best-fit model supported by the approximate Bayesian computation (ABC) analysis indicated that, D. floribunda and D. yunnanensis diverged during the mid-Pleistocene period, consistent with the largest glacial period in the Qinghai-Tibet Plateau (QTP). The historically inter-specific gene flow was identified but seemed to have ceased after the last interglacial period (LIG), when the range of D. floribunda moved northward from the south of the Sichuan Basin. Further, populations of D. floribunda had expanded obviously in the north of the Sichuan Basin after the last glacial maximum (LGM). Relatively, the range of D. yunnanensis expanded before the LGM, reduced during the post-LGM especially in the north of the Sichuan Basin, reflecting the asynchronous responses of related species to the contemporary climate changes. Our results suggested that complex topography should be considered in understanding the distributional patterns even for closely related species and their demographic responses