Monday, August 29, 2011

Inciting Brownian motion at the macro-scale

Entropy is the process of moving from order to disorder, for example one’s desk becoming cluttered after being cleaned. In many cases, lower entropy states are desirable as they connote greater order. Without doing work to decrease entropy, it generally increases at the macro level (the spacetime of objects that humans encounter on a daily basis). Entropy increases and time appears to move only forward.

At the micro scale of atoms, Brownian motion occurs (the constant jiggling of atoms), and creates an important case where the Second Law of Thermodynamics (heat eventually dissipates; systems move from being warm to cold) does not hold. Brownian motion at the micro scale also allows fluctuations in the arrow of time and in entropy, e.g.; time may flow forwards and backwards, and there may be fluctuations towards lower and higher states of entropy. This can be seen not just at the very-very small Planck scale and the atomic scale of statistical mechanics (for example, atoms jiggling in a gas), but also at the level of cells in the body, and in another example, pollen cells suspended just the right way in water.

That Brownian motion can occur at the comparatively larger scale of cells suggests that it may occur, or be induced to occur at even more macro levels too. For example, in complex adaptive systems, an economy has phases of Brownian motion, when rational agents are jiggling constantly to make the invisible hand of supply and demand meet. Perhaps incentive structures including policy may be used to facilitate the persistence of Brownian motion and devolution of entropy in macro-level systems.

Sunday, August 21, 2011

A system is a balance: complex systems design

The Inconsistency Robustness symposium held at Stanford August 16-18, 2011 featured discussion of a number of challenges that arise in the design of complex systems, and potential solutions to them. The dialogue ranged from computer science details (for example, message passing in concurrent systems) to systemic assessments (for example, ecological concerns and homeostasis). Researcher attendees applied their varied backgrounds to the discussion.

A universal point in complex systems design is the importance of expecting and incorporating inconsistency and potential points of failure into a system. Flexible robust systems may be dynamical and adaptive within boundaries (Figure 1 - "Complex Dynamical") provided there is some mechanism for identifying and monitoring potential out-of-bounds conditions.

Figure 1. Three patterns of behavior in complex dynamical systems (Source)

Sunday, August 14, 2011

Scaling citizen health science and ethical review

Many things are needed to scale citizen science from small cohorts on the order of a few individuals to medium and large-sized cohorts. Building trust in online health communities, motivating sustained engagement from study participants, and lower-cost easier-access blood tests are a few things that are needed.

Legal and ethical issues are also a challenge. Independent ethical review is appropriate but the current IRB (Institutional Review Board) requirement for funding and journal publication is a barrier to crowdsourced study growth. In 23andMe's early studies, there was a definitional debate as to whether their research constituted 'human subjects research,' and whether there was a difference in interacting with subjects in-person versus over the internet.

The U.S. HHS (Health and Human Services) definition of 'humans subjects research' is research that "obtains (1) data through intervention or interaction with the individual, or (2) identifiable private information." (45 CFR 46.102(f)) The strict reading is that any research obtained by 'interacting' with a human subject (e.g.; likely all personalized health collaboration community research) would require an IRB for the funding needed to do it at scale.

Acknowledgement: Thank you to Thomas Pickard for providing background research

Sunday, August 07, 2011

Further advance in the integration of organic and inorganic matter

A fundamental research focus in nanotechnology is the deliberate creation of organic-inorganic hybrids such as rotaxanes that have the properties of both organic and inorganic matter. These nanomaterials can greatly extend the range of control and manipulation that can occur in nanomedicine and other applications.

One interesting recent example is engineered fusion proteins, inorganic-binding peptides conjugated with bioluminescence proteins. The fusion proteins can be used as bioimaging molecular probes both targeting minerals (through fluorescence labeling) and monitoring the rate of biomineralization (through induced reactions). (Yuca et al., Biotechnol Bioeng. 2011 May;108(5):1021-30.)

Figure 1. Integrating organic and inorganic materials: graphene sheet sandwiched in the hydrophobic interior of a phospholipid

Another example (Figure 1) is graphene sheets sandwiched in the hydrophobic interior of a phospholipid. The phospholipid layers of the membrane electrically isolate the embedded graphene from the external solution which means that the composite system could be used in the development of biosensors and bioelectronic materials. (Titov et al., ACS Nano. 2010 Jan 26;4(1):229-34.)