The persistence of original soft tissues in Mesozoic fossil bone is not explained by current chemical degradation models. We identified iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from two Mesozoic dinosaurs, using transmission electron microscopy, electron energy loss spectroscopy, micro-X-ray diffraction and Fe micro-X-ray absorption nearedge structure. Iron chelators increased fossil tissue immunoreactivity to multiple antibodies dramatically, suggesting a role for iron in both preserving and masking proteins in fossil tissues. Haemoglobin (HB) increased tissue stability more than 200-fold, from approximately 3 days to more than two years at room temperature (258C) in an ostrich blood vessel model developed to test post-mortem 'tissue fixation' by cross-linking or peroxidation. HB-induced solution hypoxia coupled with iron chelation enhances preservation as follows: HB þ O 2 . HB 2 O 2 . 2O 2 þO 2 . The well-known O 2 /haeme interactions in the chemistry of life, such as respiration and bioenergetics, are complemented by O 2 /haeme interactions in the preservation of fossil soft tissues.

The idea that original soft tissue structures and the native structural proteins comprising them can persist across geological time is controversial, in part because rigorous and testable mechanisms that can occur under natural conditions, resulting in such preservation, have not been well defined. Here, we evaluate two non-enzymatic structural protein crosslinking mechanisms, Fenton chemistry and glycation, for their possible contribution to the preservation of blood vessel structures recovered from the cortical bone of a Tyrannosaurus rex (USNM 555000 [formerly, MOR 555]). We demonstrate the endogeneity of the fossil vessel tissues, as well as the presence of type I collagen in the outermost vessel layers, using imaging, diffraction, spectroscopy, and immunohistochemistry. Then, we use data derived from synchrotron FTIR studies of the T. rex vessels to analyse their crosslink character, with comparison against two non-enzymatic Fenton chemistry- and glycation-treated extant chicken samples. We also provide supporting X-ray microprobe analyses of the chemical state of these fossil tissues to support our conclusion that non-enzymatic crosslinking pathways likely contributed to stabilizing, and thus preserving, these T. rex vessels. Finally, we propose that these stabilizing crosslinks could play a crucial role in the preservation of other microvascular tissues in skeletal elements from the Mesozoic.

Properties that vary with particle size are an important feature of nanoscale materials. CdSe quantum dot nanocrystals vary in color from green–yellow to orange–red and luminesce from blue to yellow, where shorter wavelength, higher energy, electronic transitions correspond to smaller particle sizes. CdSe quantum dot nanocrystals are a visually engaging way to demonstrate quantum effects in chemistry, since their transition energies can be explained as a "particle in a box", where a delocalized electron is the particle and the nanocrystal is the box. Following the method pioneered by Xiaogang Peng and coworkers, CdSe nanocrystals are synthesized from CdO, oleic acid, elemental Se, and trioctylphosphine using a kinetic growth method in octadecene at 225 °C and a less than three-minute reaction time. This synthesis has several advantages over methods using dimethyl cadmium, a chemical that is extremely toxic, expensive, unstable, pyrophoric, and requires inert atmosphere techniques. When excited at 400 nm, the colloidal suspensions of quantum dots give relatively sharp emission spectra with ∼35-nm peak widths, indicating monodisperse particle sizes. Corresponding absorbance spectra are also of high quality.

S, J. PIRSON E. M. BOATMAN I R. 1. NETTLE MEMBERS. AIME I More than a decade ago some theoredcally derived relationships were proposed that pertnitte dthepredictionof the relative ability of reservoir fluids (oil, gas, water) to" flow sitmdtaneously within theporousstructure of rocks, While many successful predictions of ffuid-flow ratios from welis have been made from eiectric logs, tile theoretical deductions have not beett subjected to laboratory verifications. For the reiative pemeabiiity to iiquid and gas, simultaneous flow of water and air was used, employing the fatniiiar exter~al-gas-drive technique, While in theprqcess of water desaturation, the resistivities of the test cores (Woodbine sand) were nteasured. Their permeabilities varied from 10 to 280 ml. The laboratory results indicated the need forcitanging tite values of exponents in the titeoreticaliy derived fortnulas, wimreas the form of the functions of resistivities and saturations retnained as derived by titeory.Fortite reiative permeability to oil and water, titetitreecore dynamic technique was used on six cores. In tizis case it was found that the jornudas were valid witit but slight tnodification as derived by theory, to asuficient degree of accuracy for engitteering use and for well productivity prediction from electric logs.

Liquid crystals have a phase in between liquid and solid: the molecules can flow and drip but remain somewhat organized. The cholesteric liquid crystals prepared in this Activity use mixtures of molecules related to cholesterol that align in layers. Stacks of layers are rotated with respect to one another similar to DNA, spiral staircases, or screw threads. The rotation between layers increases with temperature. A color will be reflected when the pitch, the distance between layers that have the same orientation, is approximately equal to the colors wavelength of light. This change in pitch causes the color changes we see when we apply pressure to or heat or cool cholesteric liquid crystals. This Activity is suitable for exploring relationships between color, wavelength, reflection, and transmission and illustrates how temperature changes the liquid crystal's Bragg reflection wavelength. This Activity can also be used to explore the relationship between melting point and crystal packing. Because one component contains a long chain cis-alkene connected to the cholesterol molecule, packing efficiency and melting point increase as the relative amount of this component within the mixture is decreased.

Bone is an important material in many scientific disciplines because of its unique structure-property relationships, which are intrinsically dependent on its nanoscale components, bioapatite and collagen. As a living tissue, bone has evolved over hundreds of millions of years, and most vertebrates are now extinct. However, the vast majority of the relevant literature has engaged only modern bone tissues, neglecting the deep time perspective. Why?

Recent descriptions of blood vessels recovered from dinosaur bones have raised many questions regarding tissue diagenesis and the associated chemical pathways that led to preservation. Previous analyses have identified preserved elastin and collagen proteins in a variety of specimens [1][2]. In particular, the mechanical, chemical, and thermal susceptibility of fibrillar collagen is partially dependent on the degree of intermolecular crosslinking. While collagen crosslinking can be either enzymatically or non-enzymatically driven in life, in death, only non-enzymatic pathways are available. Hence, non-enzymatic intermolecular crosslinking of fibrillar collagen supermolecular networks in fossil blood vessels has been suggested as a possible contributor to tissue longevity.

Bone is a complex hierarchical structure composed of up to 98 weight % bioapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) nano-plates carefully deposited onto a nano-rope matrix of collagen protein.Bone is an intriguing composite from the perspective of biomimicry: the toughness of bone far exceeds that of the brittle bioapatite phase alone. Factors like size, purity, and location of the nanoplates all contribute to the impressive mechanical properties of bone, but quantitative mechanical performance investigations have been largely restricted to fresh, modern mammalian and avian tissues [1]. Current attempts to fabricate biomimetic bone for advanced materials applications are all based on an inherently limited understanding of the "structure of bone." In fact, the femur of a 100-ton Brachiosaurus may well be the superior analogy, versus human bone, for a fatigue-resistant structural material. To date, however, there has been no systematic investigation of the hierarchical bone structure of any extinct species. Thus, despite the potential wealth of precise evolution-driven structural information held in the bones of megafauna like Brachiosaurus, we have no demonstrated methods for characterizing the nano-scale structures of these amazing natural materials. Why?The first applications of electron microscopy to fossil bone were in the 1960s [2]. Decades later, only a handful of papers on the application of TEM to fossils can be found in the literature [3] [4]. The paleontology community has largely focused on the texture analysis of fossil bone, documenting nano-plate size and relative location/orientation with indirect X-ray methods [5]. Based on this type of data, there exists a common opinion that the bioapatite nano-plates coarsen substantially during fossilization. It should be noted, however, that even the modern synchrotron beam with a spot size of 50 μm still samples over 10 6 nano-plates simultaneously. Similarly, investigation of fossil bone composition with SEM energy-dispersive X-ray spectroscopy (EDS) also lacks sufficient spatial resolution to clearly document the nano-scale heterogeneities associated with the fossilization process.Our study had two main goals. The first was to conclusively demonstrate the presence of original bioapatite in fossil bone with a combination of standard TEM techniques. The second goal was to elucidate the presence of nano-scale structural and compositional heterogeneities in fossil bone, with direct implications for all future investigations of fossil bone texture analysis and micron-level compositional investigations. Identification of nano-scale heterogeneities was achieved with a combination of SEM and TEM. The specimen set included both fossil and modern bones. SEM specimens were small, polished sections removed from the bulk bone. TEM specimens included both finely ground fracture specimens and ion-milled thin sections, preserving the original orientation of the bioapatite nano-plate with respect to the bulk bone tissue. We believe that our TEM data conclusively demonstrates the e...