Traditional studies in biology are conducted using statistical ensemble experiments, typically using pico- to micro-molar concentrations of macromolecules. Because the molecules that comprise living cells are so small, techniques such as PCR amplification, gel blotting, fluorescence labeling and in vivo staining are used so that experimental results are observable with an unaided eye or, at most, optical magnification. Using these techniques, biologists attempt to elucidate the complex systems of interactions that give rise to the processes that make life possible. Biophysics typically addresses biological questions similar to those in biology, but the questions are asked at a molecular (i.e. low Reynolds number) level. By drawing knowledge and experimental techniques from a wide variety of disciplines (as described below), biophysicists are able to indirectly observe or model the structures and interactions of individual molecules or complexes of molecules. In addition to things like solving a protein structure or measuring the kinetics of single molecule interactions, biophysics is also understood to encompass research areas that apply models and experimental techniques derived from physics (e.g. electromagnetism and quantum mechanics) to larger systems such as tissues or organs (hence the inclusion of basic neuroscience as well as more applied techniques such as fMRI). Biophysics often does not have university-level departments of its own, but have presence as groups across departments within the fields of biology, biochemistry, chemistry, computer science, mathematics, medicine, pharmacology, physiology, physics, and neuroscience. What follows is a list of examples of how each department applies its efforts toward the study of biophysics. This list is hardly all inclusive. Nor does each subject of study belong exclusively to any particular department. Each academic institution makes its own rules and there is much mixing between departments. Biology and molecular biology - Almost all forms of biophysics efforts are included in some biology department somewhere. To include some: gene regulation, single protein dynamics, bioenergetics, patch clamping, biomechanics. Structural biology - angstrom-resolution structures of proteins, nucleic acids, lipids, carbohydrates, and complexes thereof. Biochemistry and chemistry - biomolecular structure, siRNA, nucleic acid structure, structure-activity relationships. Computer science - molecular simulations, sequence alignment, neural networks, databases. Mathematics - graph/network theory, population modeling, dynamical systems, phylogenetical analysis. Medicine and neuroscience - tackling neural networks experimentally (brain slicing) as well as theoretically (computer models), membrane permitivity, gene therapy, understanding tumors. Pharmacology and physiology - channel biology, biomolecular interactions, cellular membranes, polyketides. Physics - biomolecular free energy, biomolecular structures and dynamics, protein folding, stochastic processes, surface dynamics. Many biophysical techniques are unique to this field. Many of the research traditions in biophysics were initiated by scientists who were straight physicists, chemists, and biologists by training.