112 research outputs found

    Emergence of the mitochondrial reticulum from fission and fusion dynamics

    Get PDF
    Mitochondria form a dynamic tubular reticulum within eukaryotic cells. Currently, quantitative understanding of its morphological characteristics is largely absent, despite major progress in deciphering the molecular fission and fusion machineries shaping its structure. Here we address the principles of formation and the large-scale organization of the cell-wide network of mitochondria. On the basis of experimentally determined structural features we establish the tip-to-tip and tip-to-side fission and fusion events as dominant reactions in the motility of this organelle. Subsequently, we introduce a graph-based model of the chondriome able to encompass its inherent variability in a single framework. Using both mean-field deterministic and explicit stochastic mathematical methods we establish a relationship between the chondriome structural network characteristics and underlying kinetic rate parameters. The computational analysis indicates that mitochondrial networks exhibit a percolation threshold. Intrinsic morphological instability of the mitochondrial reticulum resulting from its vicinity to the percolation transition is proposed as a novel mechanism that can be utilized by cells for optimizing their functional competence via dynamic remodeling of the chondriome. The detailed size distribution of the network components predicted by the dynamic graph representation introduces a relationship between chondriome characteristics and cell function. It forms a basis for understanding the architecture of mitochondria as a cell-wide but inhomogeneous organelle. Analysis of the reticulum adaptive configuration offers a direct clarification for its impact on numerous physiological processes strongly dependent on mitochondrial dynamics and organization, such as efficiency of cellular metabolism, tissue differentiation and aging

    Radiation thermal processes in Cr13Mo2NbVB steel - the material of the fuel assembly shell in reactor BN-350 under mechanical tests

    Get PDF
    Regularities of changes of structural-phase state and mechanical properties of steel 13Mo2NbVB - the material of the fuel assembly shell in reactor BN-350 after various mechanical tests at 350°C are experimentally studied. The formation of microprecipitations FeMo, enriched or depleted with molybdenum was found in the short-time mechanical tests, which is the cause of thermal hardening of irradiated Cr13Mo2NbVB steel and its destruction by the ductile-brittle mechanism. On the basis of long-time creep tests it was shown that the material of the spent fuel assembly shell has sufficient resource for long-time storage in the temperature and force conditions simulating long-time storage of spent nuclear fuel

    Incompatibility of the Digital Economy Act 2010 subscriber appeal process provisions with Article 6 of the ECHR

    Get PDF
    This is the accepted manuscript of an article published by Taylor & Francis in International Review of Law, Computers and Technology on 10 January 2014. The version of record [Romero-Moreno, F. (2014) Incompatibility of the Digital Economy Act 2010 subscriber appeal process provisions with Article 6 of the ECHR', International Review of Law, Computers & Technology, 28(1): 81-97, first published on line January 10, 2014] is available online via doi: http://dx.doi.org/10.1080/13600869.2013.869912Through case-law research, this paper critically assesses the compatibility of the Digital Economy Act 2010 (DEA) subscriber appeal process provisions (Section 13 of the DEA) with Article 6 of the European Convention on Human Rights (ECHR). Drawing on the European Court of Human Rights (ECtHR) case-law, Ofcom's Initial Obligations Code (the Code), and the DEA judicial review decision, namely, BT PLC and Talk Talk PLC v Secretary of State for Business Innovation and Skills and others, this paper focuses on the three Strasbourg Court principles of equality of arms, admissibility of evidence, and presumption of innocence, in an effort to determine whether Section 13 of the DEA infringes them, and whether this constitutes a breach of a subscriber's right to a fair trial under Article 6 of the ECHR. The paper examines these three ECtHR principles. It contrasts such principles with the Code's provisions, and considers the compatibility of Section 13 of the DEA with Article 6 of the ECHR. It concludes that the DEA subscriber appeal process provisions do indeed infringe these principles, thus constituting a violation of subscribers' right to a fair trial. It also recommends that the UK government start taking seriously human rights in general, and Article 6 of the ECHR in particular.Peer reviewe

    Radiation thermal processes in Cr13Mo2NbVB steel - the material of the fuel assembly shell in reactor BN-350 under mechanical tests

    Get PDF
    Regularities of changes of structural-phase state and mechanical properties of steel 13Mo2NbVB - the material of the fuel assembly shell in reactor BN-350 after various mechanical tests at 350°C are experimentally studied. The formation of microprecipitations FeMo, enriched or depleted with molybdenum was found in the short-time mechanical tests, which is the cause of thermal hardening of irradiated Cr13Mo2NbVB steel and its destruction by the ductile-brittle mechanism. On the basis of long-time creep tests it was shown that the material of the spent fuel assembly shell has sufficient resource for long-time storage in the temperature and force conditions simulating long-time storage of spent nuclear fuel

    Improvement of the realisation of the mass scale

    Get PDF
    The project 19RPT02“Improvement of the realisation of the mass scale”(EMPIR [1] Call 2019 –Energy, Environment, Normative and Research Potential)has just started.Its aim is to improve the quality of one of the most important tasksin mass metrology,the realisation of the mass scale. After the new definition of the kilogram this technique is getting more important

    Infiltrazione macrofagica e densità capillare nel carcinoma della laringe. Studio su 52 casi

    Get PDF
    L’angiogenesi è uno dei sei principali meccanismi alla base del cancro, ed è stato studiato approfonditamente negli ultimi 20 anni. L’obiettivo del presente studio è stato quello di determinare sia la densità capillare sia l’infiltrato macrofagico nei campioni di carcinoma laringeo e di determinarne la correlazione con gli aspetti clinici e patologici. Sia la densità capillare (CD34) sia l’infiltrato macrofagico (CD68) sono stati determinati con metodiche immunoistochimiche mediante microarray. Il nostro campione ha mostrato una densità capillare media di 14,27 ± 12,92 vasi su campo ingrandito a 200×, e l’infiltrato macrofagico medio è stato di 5,19 ± 4,32. La densità capillare si è dimostrata superiore nei pazienti metastatici. Inoltre uno studio di regressione lineare ha mostrato che l’entità dell’infiltrato macrofagico poteva predire la densità capillare del campione di carcinoma laringeo preso in esame. Non abbiamo invece individuato una correlazione fra ambo i fattori studiati e l’incidenza delle recidive o gli altri fattori clinici presi in esame. Il nostro studio aggiunge dati ad un problema che per quanto studiato a fondo negli ultimi 20 anni resta nella sostanza controverso

    Peripubertal serum concentrations of organochlorine pesticides and semen parameters in Russian young men.

    Get PDF
    BACKGROUND: Epidemiologic literature on the relation of organochlorine pesticides (OCPs) with semen quality among adult men has been inconclusive, and no studies have prospectively explored the association between peripubertal serum OCPs and semen parameters in young men. OBJECTIVE: To evaluate prospective associations of peripubertal serum concentrations of hexachlorobenzene (HCB), β-hexachlorocylohexane (β-HCH), and p,p\u27-dichlorodiphenyldichloroethylene (p,p\u27-DDE) with semen parameters among young Russian men. METHODS: This prospective cohort study included 152 young men who enrolled in the Russian Children\u27s Study (2003-2005) at age 8-9 years and were followed annually until young adulthood. HCB, β-HCH, and p,p\u27-DDE concentrations were measured at the CDC by mass spectrometry in serum collected at enrollment. Between 18 and 23 years, semen samples (n = 298) were provided for analysis of volume, concentration, and progressive motility; we also calculated total sperm count and total progressive motile count. Linear mixed models were used to examine the longitudinal associations of quartiles of serum HCB, β-HCH and p,p\u27-DDE with semen parameters, adjusting for total serum lipids, body mass index, smoking, abstinence time and baseline dietary macronutrient intake. RESULTS: Lipid-adjusted medians (IQR) for serum HCB, βHCH and p,ṕ-DDE, respectively, were 150 ng/g lipid (102-243), 172 ng/g lipid (120-257) and 275 ng/g lipid (190-465). In adjusted models, we observed lower ejaculated volume with higher serum concentrations of HCB and βHCH, along with reduced progressive motility with higher concentrations of βHCH andp,ṕ-DDE. Men in the highest quartile of serum HCB had a mean (95% Confidence Interval, CI) ejaculated volume of 2.25 mL (1.89, 2.60), as compared to those in the lowest quartile with a mean (95% CI) of 2.97 mL (2.46, 3.49) (p = 0.03). Also, men in the highest quartile of serum p,ṕ-DDE had a mean (95% CI) progressive motility of 51.1% (48.6, 53.7), as compared to those in the lowest quartile with a mean (95% CI) of 55.1% (51.7, 58.5) (p = 0.07). CONCLUSION: In this longitudinal Russian cohort study, peripubertal serum concentrations of selected OCPs were associated with lower ejaculated volume and progressive motility highlighting the importance of the peripubertal window when evaluating chemical exposures in relation to semen quality

    Trans-mitochondrial coordination of cristae at regulated membrane junctions

    Get PDF
    Reminiscent of bacterial quorum sensing, mammalian mitochondria participate in inter-organelle communication. However, physical structures that enhance or enable interactions between mitochondria have not been defined. Here we report that adjacent mitochondria exhibit coordination of inner mitochondrial membrane cristae at inter-mitochondrial junctions (IMJs). These electron-dense structures are conserved across species, resistant to genetic disruption of cristae organization, dynamically modulated by mitochondrial bioenergetics, independent of known inter-mitochondrial tethering proteins mitofusins and rapidly induced by the stable rapprochement of organelles via inducible synthetic linker technology. At the associated junctions, the cristae of adjacent mitochondria form parallel arrays perpendicular to the IMJ, consistent with a role in electrochemical coupling. These IMJs and associated cristae arrays may provide the structural basis to enhance the propagation of intracellular bioenergetic and apoptotic waves through mitochondrial networks within cells

    The production of platinum-coated silicate nanoparticle aggregates for use in hypervelocity impact experiments

    Get PDF
    We present a method for producing metal-coated low-density (?3) aggregate silicate dust particles for use in hypervelocity impact (HVI) experiments. Particles fabricated using the method are shown to have charged and electrostatically accelerated in the Max Planck Institut für Kernphysik (MPI-K) 2 MV Van de Graaff accelerator, allowing the production of impact ionization mass spectra of silicate particles (impacting at velocities ranging from ?1 to >30 km s?1, corresponding to sizes of >1 ?m to <0.1 ?m) using the Large Area Mass Analyser (LAMA) instrument, designed for cosmic dust detection in space. Potential uses for the coated grains, such as in the calibration of aerogel targets similar to those used on the Stardust spacecraft, are also discussed
    corecore