The Grand Finale – Farewell to Cassini

On September 15, 2017, Cassini will enter Saturn’s atmosphere and break into very small pieces before burning up entirely.  For the past 7 years, the satellite’s exploration of Saturn and its moons has resulted in valuable data and glorious images.  Now as it runs out of fuel it will begin it’s final mission—a deep dive into Saturn’s atmosphere sending data back to Earth for as long as it can.

Personally, I find it difficult to avoid anthropomorphizing these space vehicles, especially one I have observed closely for so long, and watching this final mission continues to be quite moving to me. The remarkable images of Saturn’s rings were my desktop background and I closely watched the craft travel to the moons. I followed Cassini’s Twitter feed (CassiniSaturn) and saw the images and data come in daily.  Now this week I watch it end, and as NASA said in one of their animations, Cassini will become part of Saturn itself.  (To see details and to watch the amazing animation, see NASA’s “Grand Finale Toolkit.”)

Here at Annual Reviews, our authors have been using the data from Cassini’s exploration of Saturn for many years, and we are highlighting some of those articles during the culmination of Cassini’s mission.

Thank you, Cassini.

spencer-cassiniEnceladus: An Active Ice World in the Saturn System” by John R. Spencer and Francis Nimmo.  Annual Review of Earth and Planetary Sciences, Volume 41

Planetary Reorientation” by Isamu Matsuyama, Fancis Nimmo, and Jerry X. Mitrovica.  Annual Review of Earth and Planetary Sciences, Volume 42

mitchell-cassiniThe Climate of Titan” by Jonathan L. Mitchell and Juan M. Lora Annual Review of Earth and Planetary Sciences, Volume 44

Shape, Internal Structure, Zonal Winds, and Gravitational Field of Rapidly Rotating Jupiter-Like Planets” by Keke Zhang, Dali Kong, and Gerald Schubert.  Annual Review of Earth and Planetary Sciences, Volume 45

Hayes-cassini

The Lakes and Seas of Titan” by Alexander G. Hayes Annual Review of Earth and Planetary Sciences, Volume 44

 

 

 

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.

The Science of Art and Plant Monitoring: Annual Review of Analytical Chemistry Volume 10

Browse the Annual Review of Analytical Chemistry Volume 10 table of contents.

AC10-artThere’s something magical about how scientific technology and techniques can peel back layers of paint and dust to reveal new information about an object or artist. Karen Trentelman’s article “Analyzing the Heterogeneous Hierarchy of Cultural Heritage Materials: Analytical Imaging” only increased my enjoyment of the topic. I was especially intrigued by the approach laid out in the introduction:

“In the creation of works of art, the extent to which human activity is necessary or able to control the final product can also be considered in terms of different length scales. Generally, the most important macroscale property, and the one entirely controlled (or at least actively sought) by the artist, is the overall appearance, broadly understood to include qualities such as color, texture, sheen, and shape. However, although the artist may control the final appearance through the selection and exploitation (whether deliberate or incidental) of specific mesoscale (or smaller) properties, the intrinsic micro- to nanoscale physics and chemistry that produce the desired macroscale appearance are out of the artist’s control. For example, a layer of varnish only a few tens of microns thick can dramatically change the appearance of a painting; the artist can control the choice of varnish and the thickness and method of application, but the index of refraction and surface tension properties that impart the desired saturation of color and surface appearance are controlled by nature.”

The ideas in Kwak et al.’s article “Nanosensor Technology Applied to Living Plant Systems” took me a bit by surprise. I knew that there was research that involved precision monitoring of agriculture, but I didn’t realize that plants could be actively managed at this level with great potential to change the way agriculture works:

“In the field of plant biology or agriculture, nanosensors have been used as nanobiosensors environmental pollution (25). Several nanosensors have been developed to detect contaminants, such as crystal violet or malachite green concentrations in seafood, and parathion residues or residues of organophosphorus pesticides on vegetables)…. The installation of nanosensors or nanoscale wireless sensors in living plants is currently applied to enable the real-time monitoring and early detection of potential problems related to biochemistry and metabolism.”

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.

 

Historical Context: Annual Review of Biochemistry Volume 86

Browse the Annual Review of Biochemistry Volume 86 table of contents.

This volume of the Annual Review of Biochemistry opens with an autobiography by Christopher Walsh, titled “At the Intersection of Chemistry, Biology, and Medicine.” I especially enjoyed his memories of his early days in research and how these early projects shaped his long-term research:

“Two epiphanies turned my attention away from medical school, which had
been my default expectation, to biomedical research as a career option. The
first came from research on fire ant trail substance pheromone. I was involved
in a joint project between Professor Law and Professor E.O. Wilson in the
Biology Department. Wilson has been the world’s expert in ant biology and the
lessons learned from their interdependent society for the past 60-plus years.
My efforts at partial purification resulted in my initial research paper,
published in Nature no less. Although it would be another 30 years before I
published in Nature again, in my callow enthusiasm I thought from this
encounter that the research enterprise would be exciting.”

I also liked the description of his first research group:

“Starting a research group is like diving into the deep end of a pool to find out if you can swim, with no prior instructions on what keeps people afloat. At the outset, aged 28, I was at most 5 years older than the students in my group. The sales and instrument people who would drop by would ask me all the time if Professor Walsh was in. I usually replied that unfortunately he was otherwise occupied.”

Nielsen’s article “Systems Biology of Metabolism” is a wide-ranging article that gave me a better understanding of metabolism—a subject I’m interested in but find very complicated. I especially enjoyed the history of the subject in the Introduction to the article, including the “golden age of metabolism studies.” These bits of history are very useful context.
bi-ribosomal rnaI discovered another historical section in Matzov’s article, “A Bright Future for
Antibiotics?

“This article addresses a major problem in modern medicine: resistance of pathogens to antibiotics. It focuses on how antibiotics paralyze ribosomes, the universal multicomponent cellular particles that translate the genetic code into proteins. It highlights conventional and nonconventional suggestions that may relieve, to some extent, the current problematic medical situation and shows how we may benefit from the vast amount of available structural information. Notably, understanding the mechanisms of resistance to antibiotics could not even be dreamt about when a project aimed at the determination of the atomic structure of ribosomes was started during the last two weeks of November 1979.”

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.

Ice Crystals and Ice Cream: Annual Review of Materials Research Volume 47

Browse the Annual Review of Materials Research Volume 47 table of contents.

I am thrilled to introduce you to “Physical Dynamics of Ice Crystal Growth” by Libbrecht. This article provided me with a welcome break from the heat and inspired a great deal of respect for this field (as well as a snow dance in my office chair). It’s a really great article and I hope you go take a look—even if just to gaze in wonder at the figures.

MR47-ice

“The winter clouds produce a great diversity of snow-crystal forms, from slender columns to thin plates, at times branched, sectored, hollowed, and faceted, as shown in Figure 1. Yet extensive laboratory and theoretical investigations have still not determined why these varied structures appear under different growth conditions. For example, we do not yet possess even a qualitative understanding of why snow crystal growth alternates between plate-like and columnar forms as a function of temperature, as seen in Figure 1, although this behavior was first observed more than 75 years ago.”

I would be willing to bet that most of us have bent a spoon while attempting to scoop hard ice cream. A few of us have gone on to write scientific papers about it, as I discovered in the article by Sethna et al. “Deformation of Crystals: Connections with Statistical Physics.”

MR47-ice cream“A metal spoon will spring back into its original shape under ordinary use, but when scooping hard ice cream, one may bend the spoon too far for it to recover (Figure 1). The spoon is made up of many crystalline grains, each of which has a regular grid of atoms. To permanently deform the spoon, atomic planes must slide past one another. Such glide happens through the motion of dislocation lines. The dynamics, interactions, and entanglement of these dislocation lines form the microscopic underpinnings of crystal plasticity, inspiring this review.”

It’s a noisy world out there and I’ve often wished for better soundproofing.  I was not aware of the complexity of those sound barriers until discovering Yang & Sheng’s article, “Sound Absorption Structures: From Porous Media to Acoustic Metamaterials.” I particularly enjoyed the early section on “traditional porous materials such as plastic foam, fiber glass, and mineral wool.”

“Because sound is associated with very small air displacement velocities, its dissipation as a function of frequency must obey the linear response theory, in which the generalized flux (e.g., electrical current density, flow rate, heat flux) is linearly proportional to the generalized force (e.g., gradients of electrical potential, pressure, temperature). Because dissipative force varies linearly as function of the rate (e.g., dynamic friction varies linearly as a function of relative velocity) and dissipated power is given by the product of force and flux, it follows that sound dissipation is a quadratic function of frequency, as shown below. Hence, for low frequency sound, dissipation is inherently much weaker than for high-frequency sound.”

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.

 

Brewing Science and a Fantastic Interview: Annual Review of Chemical and Biomolecular Engineering Volume 8

Browse the Annual Review of Chemical and Biomolecular Engineering Volume 8 table of contents.

While some home brewers may appreciate the more detailed breakdown of the various ingredients and each stage of the brewing process in the article by Dr. Bamforth, “Progress in Brewing Science and Beer Production,” I enjoyed the opening section on the history of brewing:

“Despite the enormous depths of understanding of the brewing process, it is nevertheless a fact that the fundamental shape of the brewing process has not changed in millennia. Were one to be time-transported to the Middle Ages, one would find fundamentally the same unit operations that continue to be employed in the brewing of beer.”

CH9-McKettaI’m always delighted to read the autobiographies, or watch the video interviews, especially when the subject turns out to be a wonderful storyteller.  I really enjoyed “A Conversation with John McKetta” by Thomas Truskett.   The questions were interesting and the answers revealed a few of McKetta’s extraordinary experiences:

“I looked forward to the time when I could work in the mine because they paid you $0.25 for every ton that you brought to the surface. And I did this after I graduated from high school. I just couldn’t wait until the day that I could go into the mines…until I went that first day, and then I hated it. I never liked it all. What happened was, our mine was 100 and some feet deep—that’s kind of shallow. And the first day that we were in the mines, the couple working right next to us were under a fall. There was a rock fall over their heads. And it took us a couple of days to scrape away the dirt and get them out as well as we could. And of course, they were dead the minute the rock hit them. So I just hated it.”

I’ve been hearing about the possibility of making oil from algae since childhood when my grandfather mentioned it as we were fishing at a local pond with some spectacular algae infestations. I found the note in the abstract of “Algae to Economically Viable Low-Carbon-Footprint Oil” by Bhujade, Chidambaram, Kumar & Sapre  about the historically cyclical research really interesting:

“Whenever crude prices declined, research on algae stopped. The scenario today is different. Even given low and volatile crude prices ($30–$50/barrel), interest in algae continues all over the world. Algae, with their cure-all characteristics, have the potential to provide sustainable solutions to problems in the energy-food-climate nexus. However, after years of effort, there are no signs of algae-to-biofuel technology being commercialized.”

 

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.

Annual Review of Biomedical Engineering Volume 19

Browse the Annual Review of Biomedical Engineering Volume 19 table of contents.

I’ve noticed a lot of articles recently about wearable and insertable technologies.   “Energy Harvesting from the Animal/Human Body for Self-Powered Electronics” by Dagdeviren, Li & Wang is the first article I recall discussing how to use the subjects wearing the technology to power the batteries as well! Personally, I love the idea of charging my cellphone via a brisk walk around the block. The authors point out there are many energy sources available:

BE19-wearable“Although there are various applicable energy sources for harvesters, including sunlight, IR light from the environment, and radio-frequency power sources through inductive coupling, the body of a living subject is a particularly favorable energy source, given the vast number and wide variety of available energies. For instance, theoretical calculations have demonstrated that body heat, breathing, and arm movements can generate 2.8–4.8 W, 0.83 W, and 60 W, respectively. Although these power sources could offer a compelling way to accommodate the operation of a cardiac pacemaker (50 μW for 7 years), a hearing aid (1 mW for 5 days), and a smartphone (1 W for 5 h), practical demonstrations are needed to show the feasibility of powering such electronics.”

I feel like I have followed many of the ideas presented in Black, Perez-Pinera & Gersbach’s article “Mammalian Synthetic Biology: Engineering Biological Systems” from science fiction to reality. These synthetic circuits could offer new ways to treat many diseases and genetic problems:

“Synthetic biology aims to create new biological functions through the design and controlled assembly of genetic circuits. A genetic circuit is a combination of biological parts that together execute a defined function within a host organism. By deconstructing natural genetic circuits that have been refined by evolution and reconstructing them from modular components, synthetic biologists can gain insight into the structure–function relationship of natural biological systems and use this information to build systems with novel activity.”

 

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.

The Complicated Immune Response: Annual Review of Immunology, Volume 35

Browse the Annual Review of Immunology, Volume 35 table of contents.

While proofing this volume, I was impressed again by how complicated the immune system is. It seemed so very simple in high school biology! But there are so many related actions that have to happen in precise sequences, and even systems that I thought were disconnected from immunity turn out to be quite important. For instance, see the abstract of “The Lymphatic System: Integral Roles in Immunity” by Gwendalyn Randolph et al.:IY35-lymphatic

The lymphatic vasculature is not considered a formal part of the immune system, but it is critical to immunity. One of its major roles is in the coordination of the trafficking of antigen and immune cells. However, other roles in immunity are emerging. Lymphatic endothelial cells, for example, directly present antigen or express factors that greatly influence the local environment.

The study of immunology has progressed in recent years and is producing huge amounts of data—as I discovered in Arup K. Chakraborty’s article, “A Perspective on the Role of Computational Models in Immunology.” To make use of that data, because the processes are so complex, researchers are using computational models:

Computational or theoretical studies of the model can keep track of every possible event that can occur consistent with a hypothesis and reveal whether a particular hypothesis is plausible. Hypotheses that appear feasible at first glance can be incorrect because of the complexity of the underlying phenomena. Computational biophysics–based models not only can screen out these hypotheses prior to fruitless experimental tests, but also can shed light on the reason a hypothesis is unlikely to be right and thus guide the choice of other feasible hypotheses. Such computational studies are not exercises in fitting parameters to quantitate known mechanistic models. Rather they offer ways to obtain mechanistic insights and guide the choice of meaningful hypotheses underlying puzzling observations and the design of realistic experiments that can test the hypotheses.

Another article that caught my interest was Kole T. Roybal &Wendell A. Lim’s “Synthetic Immunology: Hacking Immune Cells to Expand Their Therapeutic Capabilities.” I was intrigued by the title’s use of “hacking” in a biomedical context and the article itself proved to be fascinating!

[I]mmune cells are relatively easy to remove, modify, and transfer back into a patient. Given these unique properties, immune cells provide a remarkable platform for interfacing with and treating disease. There are many complex diseases, such as cancer and autoimmunity, that our natural immune systems either cannot handle or pathologically contribute to. Thus, there is a strong rationale to engineer new disease sensing and response behaviors in immune cells, especially given recent powerful advances in synthetic biology and genome editing, which give us unprecedented ability to modify and engineer cellular functions.

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.