IR Signature of NO Binding to a Ferrous Heme Center

2013 ◽  
Vol 4 (15) ◽  
pp. 2414-2417 ◽  
Author(s):  
Francesco Lanucara ◽  
Debora Scuderi ◽  
Barbara Chiavarino ◽  
Simonetta Fornarini ◽  
Philippe Maitre ◽  
...  
Keyword(s):  
Ir Signature ◽  
Ferrous Heme

Numerical evaluation of the exhaust-direction effects on plume flow and helicopter infrared radiation under hover and cruise statuses

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zongyao Yang ◽  
Yong Shan ◽  
Jingzhou Zhang
Keyword(s):  
Radiation Intensity ◽  
Infrared Radiation ◽  
Design Methodology ◽  
Main Rotor ◽  
Content Type ◽  
Exhaust Plume ◽  
Ir Signature ◽  
Plume Flow ◽  
The Impact ◽  
Rotational Direction

Purpose This study aims to investigate the effects of exhaust direction on exhaust plume and helicopter infrared radiation in hover and cruise status. Design/methodology/approach Four exhaust modes are concerned, and the external flow field and fuselage temperature field are calculated by numerical simulation. The infrared radiation intensity distributions of the four models in hovering and cruising states are computed by the ray-tracing method. Findings Under the hover status, the exhaust plume is deflected to flow downward after it exhausts from the nozzle exit, upon the impact of the main-rotor downwash. Besides, the exhaust plume shows a “swirling” movement following the main-rotor rotational direction. The forward-flight flow helps prevent the hot exhaust plume from a collision with the helicopter fuselage generally for the cruise status. In general, the oblique-upward exhaust mode provides moderate infrared radiation intensities in all of the viewing directions, either under the hover or the cruise status. Compared with the hover status, the infrared radiation intensity distribution alters somewhat in cruise. Originality/value Illustrating the influences of exhaust direction on plume flow and helicopter infrared radiation and the differences of helicopter infrared radiation under hover and cruise statuses are identified. Finally, an appropriate exhaust mode is proposed to provide a better IR signature distribution.

Electronic structure of nitrosyl ferrous heme complexes

1989 ◽  
Vol 111 (8) ◽  
pp. 2767-2772 ◽  
Author(s):  
Ahmad Waleh ◽  
Nan Ho ◽  
Lek Chantranupong ◽  
Gilda H. Loew
Keyword(s):  
Electronic Structure ◽  
Ferrous Heme

scholarly journals IR Signature of Size-Selective CO2 Activation on Small Platinum Cluster Anions, Pt n − (n =4-7)

2018 ◽  
Vol 130 (45) ◽  
pp. 15038-15042 ◽  
Author(s):  
Alice E. Green ◽  
Jasmin Justen ◽  
Wieland Schöllkopf ◽  
Alexander S. Gentleman ◽  
André Fielicke ◽  
...  
Keyword(s):  
Co2 Activation ◽  
Cluster Anions ◽  
Platinum Cluster ◽  
Ir Signature

scholarly journals Heme oxygenase-2 (HO-2) binds and buffers labile heme, which is largely oxidized, in human embryonic kidney cells

2021 ◽  
Author(s):  
David A Hanna ◽  
Courtney M Moore ◽  
Liu Liu ◽  
Xiaojing Yuan ◽  
Angela S Fleischhacker ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Physiological Function ◽  
Hek293 Cells ◽  
Kidney Cells ◽  
Human Embryonic Kidney ◽  
Human Embryonic Kidney Cells ◽  
Heme Oxygenases ◽  
Heme Trafficking ◽  
Ferrous Heme

Heme oxygenases (HO) detoxify heme by oxidatively degrading it into carbon monoxide, iron, and biliverdin, which is reduced to bilirubin and excreted. Humans express two isoforms: inducible HO-1, which is up-regulated in response to various stressors, including excess heme, and constitutive HO-2. While much is known about the regulation and physiological function of HO-1, comparatively little is known about the role of HO-2 in regulating heme homeostasis. The biochemical necessity for expressing constitutive HO-2 is largely dependent on whether heme is sufficiently abundant and accessible as a substrate under conditions in which HO-1 is not induced. By measuring labile heme, total heme, and bilirubin in human embryonic kidney HEK293 cells with silenced or over-expressed HO-2, and various HO-2 mutant alleles, we found that endogenous heme is too limiting to support HO-2 catalyzed heme degradation. Rather, we discovered that a novel role for HO-2 is to bind and buffer labile heme. Taken together, in the absence of excess heme, we propose that HO-2 regulates heme homeostasis by acting as a heme buffering factor in control of heme bioavailability. When heme is in excess, HO-1 is induced and both HO-2 and HO-1 can provide protection from heme toxicity by enzymatically degrading it. Our results explain why catalytically inactive mutants of HO-2 are cytoprotective against oxidative stress. Moreover, the change in bioavailable heme due to HO-2 overexpression, which selectively binds ferric over ferrous heme, is consistent with the labile heme pool being oxidized, thereby providing new insights into heme trafficking and signaling.

scholarly journals Polarization Microscopy and Infrared Microspectroscopy of Integument Coverings of Diapausing Larvae in Two Distantly Related Nonsocial Bees

2018 ◽  
Vol 24 (1) ◽  
pp. 75-81
Author(s):  
Maria Luiza S. Mello ◽  
Benedicto de Campos Vidal ◽  
Jerome G. Rozen
Keyword(s):  
High Performance ◽  
Construction Materials ◽  
Positive Staining ◽  
Polarization Microscopy ◽  
Transparent Films ◽  
Social Bees ◽  
Sudan Black B ◽  
Ft Ir ◽  
Ir Signature ◽  
Arid Desert

AbstractThe larvae of the two distantly related nonsocial bees Ericrocis lata (Apidae) and Hesperapis (Carinapis) rhodocerata (Melittidae), which develop mostly under arid desert areas of North America, and that differ in that they either spin (E. lata) or do not spin (H. rhodocerata) protective cocoons before entering diapause, produce transparent films that cover the larval integument. To understand the nature of these films, their responses to topochemical tests and their characteristics when examined with fluorescence and high-performance polarization microscopy and microspectroscopy were studied. A positive staining by Sudan black B, birefringence of negative sign, and a Fourier transform-infrared (FT-IR) spectrum typical of lipids were detected for the integument covering of both species. The FT-IR signature, particularly, suggests a wax chemical composition for these lipid coverings, resembling the waxes that are used as construction materials in the honey cells produced by social bees. Considering the arid environmental conditions under which these larvae develop, we hypothesize that their covering films may have evolved as protection against water depletion. This hypothesis seems especially appropriate for H. rhodocerata larvae, which are capable of undergoing a long diapause period in the absence of a protective cocoon.

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