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  • Chemical Engineering  (3)
  • critical phenomena  (2)
  • 3-Hydroxybutyric Acid/metabolism  (1)
  • 85.30  (1)
  • 1
    Publikationsdatum: 2016-03-17
    Beschreibung: The energetic burden of continuously concentrating solutes against gradients along the tubule may render the kidney especially vulnerable to ischaemia. Acute kidney injury (AKI) affects 3% of all hospitalized patients. Here we show that the mitochondrial biogenesis regulator, PGC1alpha, is a pivotal determinant of renal recovery from injury by regulating nicotinamide adenine dinucleotide (NAD) biosynthesis. Following renal ischaemia, Pgc1alpha(-/-) (also known as Ppargc1a(-/-)) mice develop local deficiency of the NAD precursor niacinamide (NAM, also known as nicotinamide), marked fat accumulation, and failure to re-establish normal function. Notably, exogenous NAM improves local NAD levels, fat accumulation, and renal function in post-ischaemic Pgc1alpha(-/-) mice. Inducible tubular transgenic mice (iNephPGC1alpha) recapitulate the effects of NAM supplementation, including more local NAD and less fat accumulation with better renal function after ischaemia. PGC1alpha coordinately upregulates the enzymes that synthesize NAD de novo from amino acids whereas PGC1alpha deficiency or AKI attenuates the de novo pathway. NAM enhances NAD via the enzyme NAMPT and augments production of the fat breakdown product beta-hydroxybutyrate, leading to increased production of prostaglandin PGE2 (ref. 5), a secreted autacoid that maintains renal function. NAM treatment reverses established ischaemic AKI and also prevented AKI in an unrelated toxic model. Inhibition of beta-hydroxybutyrate signalling or prostaglandin production similarly abolishes PGC1alpha-dependent renoprotection. Given the importance of mitochondrial health in ageing and the function of metabolically active organs, the results implicate NAM and NAD as key effectors for achieving PGC1alpha-dependent stress resistance.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tran, Mei T -- Zsengeller, Zsuzsanna K -- Berg, Anders H -- Khankin, Eliyahu V -- Bhasin, Manoj K -- Kim, Wondong -- Clish, Clary B -- Stillman, Isaac E -- Karumanchi, S Ananth -- Rhee, Eugene P -- Parikh, Samir M -- K08-DK090142/DK/NIDDK NIH HHS/ -- K08-DK101560/DK/NIDDK NIH HHS/ -- P30-DK079337/DK/NIDDK NIH HHS/ -- R01 DK095072/DK/NIDDK NIH HHS/ -- R01-DK095072/DK/NIDDK NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2016 Mar 24;531(7595):528-32. doi: 10.1038/nature17184. Epub 2016 Mar 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA. ; Center for Vascular Biology Research, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA. ; Division of Clinical Chemistry, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA. ; Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA. ; Bioinformatics and Systems Biology Core, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA. ; Nephrology and Endocrine Divisions, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA. ; Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02139, USA. ; Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26982719" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): 3-Hydroxybutyric Acid/metabolism ; Acute Kidney Injury/drug therapy/*metabolism ; Adipose Tissue/drug effects/metabolism ; Amino Acids/metabolism ; Animals ; Cytokines/metabolism ; Dinoprostone/biosynthesis/metabolism ; Humans ; Ischemia/drug therapy/metabolism ; Kidney/drug effects/*metabolism/physiology/physiopathology ; Male ; Mice ; Mice, Inbred C57BL ; Mitochondria/metabolism ; NAD/*biosynthesis ; Niacinamide/deficiency/pharmacology/therapeutic use ; Nicotinamide Phosphoribosyltransferase/metabolism ; Oxidation-Reduction ; Signal Transduction/drug effects ; Stress, Physiological ; Transcription Factors/deficiency/*metabolism
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 16 (1978), S. 279-287 
    ISSN: 1432-0630
    Schlagwort(e): 42.80 ; 85.30
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract Optical projection of masks is a very troublesome task if dimensions are in the submicron range. It is difficult to get an undistorted image in the resist. This problem can be overcome by introducing corrections in the penultimate mask. Till now this has been done by a trial and error method in which an acceptable pattern is made only after a time consuming iterative process. In this paper a description will be given of the image forming process in which diffraction at the penultimate mask and at the aperture of the lens are the critical features. Based upon this theory correction formulas are derived for the direct design of penultimate masks. Rules for maximum edge sharpness are given, so that the tolerance demands on the production process can be relaxed. Extensive experimental measurements are in good agreement with theory. It will be shown theoretically as well as practically that by asymmetrical arrangement of the optical system images of gratings with 0.2–0.3 μm linewidth can be obtained.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    International journal of thermophysics 13 (1992), S. 1043-1052 
    ISSN: 1572-9567
    Schlagwort(e): carbon dioxide ; critical parameters ; critical phenomena ; ethane ; plait point
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract This paper deals with an evaluation of the critical parameters reported for mixtures of carbon dioxide and ethane. Equations are presented for the critical parameters as a function of the concentration.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    International journal of thermophysics 20 (1999), S. 1339-1366 
    ISSN: 1572-9567
    Schlagwort(e): critical phenomena ; parallel-plate method ; thermal conductivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A description is presented of the construction and operating procedure of an improved guarded parallel-plate instrument for measuring the thermal conductivity of fluids in the critical region. With the improved arrangement, it has been possible to reduce the temperature differences across the fluid layer between the two horizontal plates to values as low as 0.3 mK, thus allowing the thermal conductivity of fluids to be measured at temperatures as close as 20 mK to the critical temperature. The instrument has been used to measure the thermal conductivity of methane and of a mixture of methane and ethane in the close vicinity of the critical point.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 38 (1992), S. 1871-1880 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The dynamic behaviour of an adiabatic tubular plant reactor during the startup is demonstrated, together with the impact of a feed-pump failure of one of the reactants. A dynamic model of the reactor system is presented, and the system response is calculated as a function of experimentally-determined, time-dependent, manipulated variables. The values of model parameters are estimated by using the SimuSolv (1991) computer program. The data set collected during the reactor start-up is used for the parameter estimation procedure. An excellent agreement is obtained between the experimental and the calculated system response. Many continuously-operated commercial reactors require a complete conversion of one of the main reactants at the reactor exit. It is shown that for an industrial tubular reactor a much higher initial reactor temperature is required during the startup, compared to the reactor inlet temperature during normal steady-state operation, to ensure a complete reactant conversion. Much more research is necessary to determine whether this is a generally valid rule.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 503-515 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The safeguarding methodology of chemical plants is usually based on controlling the instantaneous values of process state variables within a certain operating window, the process being brought to shutdown when operating constraints are exceeded. This method does not necessarily prevent chemical reactors suffering from a runaway during dynamic operations because (a) excessive amounts of unreacted chemicals can still accumulate in the process, and (b) no means are provided to the operating personnel to identify hazardous process deviations. A model-based startup and safeguarding procedure is developed for an industrial adiabatic tubular reactor to improve process safety during startup. The trajectories of manipulated variables are calculated by minimizing the amount of one of the main reactants in the reactor effuent. It is concluded that proper control of the initial reactor temperature profile is critical for a safe startup while the impact of other manipulated variables is relatively smaller than that of the initial reactor temperature profile.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 148-158 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Rules are presented for the startup of an adiabatic tubular reactor, based on a qualitative analysis of the dynamic behavior of continuously-operated vapor- and liquid-phase processes. The relationships between the process dynamics, operating criteria, and operating constraints are investigated, since a reactor startup cannot be isolated from an entire plant startup. Composition control of the process material is critical to speed up plant startup operations and to minimize the amount of offgrade materials. The initial reactor conditions are normally critical for a successful startup. For process conditioning, a plant should have an operating mode at which the reactor can be included in a recycle loop together with its feed system and downstream process section. Experimental data of an adiabatic tubular reactor startup and thermal runaway demonstrate some operational problems when such an intermediate operating stage is missing. The derived rules are applied to an industrial, highly heat-integrated reactor section, and the resulting startup strategy is summarized in an elementary-step diagram.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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