BUILDING BRIDGES BETWEEN
THE PHYSICALAND BIOLOGICALSCIENCES
B.W. NINHAM1✍and M. BOSTRÖM2
1✍Research School of Physical S ciences and Engineering, Australian National University, 0200 Canberra, Australia
2 Department of Physics and Measurement Technology, Linköping University, SE-581 83 Linköping, Sweden
Fax: +61 2 6125 0732; E-mail: Barry.Ninham@anu.edu.au
Received March 31, 2005; Accepted April 14, 2005; Published December 16, 2005
Abstract- This paper attempts to identify major conceptual issues that have inhibited the application of physical chemistry to problems
in the biological sciences. We will trace out where theories went wrong, how to repair the present foundations, and discuss current
progress toward building a better dialogue.
Key words:Hofmeister series, dissolved gases, language of shape, conceptual locks, intermolecular forces
If all the seas were one sea,
what a great sea that would be.
If all the trees were one tree,
what a great tree that would be.
If all the men were one man,
what a great man he would be.
And if the great man took a great axe,
and chopped down the great tree,
what a huge splish splach that would be!
Unknown or Dr. Zeuss
In 1900, in Paris, at the world congress of
Mathematicians, David Hilbert enunciated his famous 23
propositions. These delineated the last outstanding
unsolved problems of mathematics. Once solved, the
edifice was to have been complete.
But unlike St. Augustine’s Eternal City of God which is
still with us, very soon thereafter cracks appeared in the
edifice. Non Euclidean Geometries, previously a
mathematical curiosity, emerged as the real language of
space and nature. There were problems with the infinite,
the calculus, and with much else. Until finally, in 1933,
Goedel’s theorem put paid to the whole rigorisation
enterprisea. This was the day the music really died.
The notion of absolute proof had gone. Mathematics
abdicated its former role as queen of the sciences. There
were now not one, but many mathematics. The sciences
were infinitely poorer for it. The catastrophe which befell
Mathematics is described by Morris Kline in his beautiful
book, Mathematics: The Loss of Certainty (23).
Something similar but in lower key has happened to the
physicists who are not so stridently confident as they once
were. And bemused that they have not been able to
contribute, conceptually, to the new molecular biology as
they once imagined they should.
The biologists, triumphant in the first flush of success
of a new science, gallop across the desert sweeping all
before, like the first followers of Mohammad crying "Allah
akbar", with DNAthe new God. (And curiously too, as for
mathematics, there are now not one, but many specialist
Cellular and Molecular BiologyTM51, 803-813
2005 Cell. Mol. Biol.
The physical chemists, the marines as it were of the
army of physical scientists in their attempts to build a
bridge between biology and the physical sciences, have
failed signally. There is an almost complete disjunction
between the biological and physical sciences. This is not to
say that biologists do not use the experimental tools and
language of the physical sciences. Of course they do, from
electron microscopes to X-rays and neutron scattering,
from computers to pH and buffers. But the role for the
physical sciences in biology seems to be ancillary and
irrelevant. The modeling that is done is imitative, not
This is genuinely puzzling, for reductionistsb.
Almost a century ago now d’Arcy Thompson, in his
famous book ‘On Growth and Form" (16), reported the
views of the early founders of the cell theory of biology and
of the physiologists. They believed that progress in their
sciences would depend on advances in understanding of
molecular forces, in what we now call colloid, surface and
solution chemistry. This simply did not happen.
(Nanotechnology and biotechnology are fashionable
words that have replaced colloid, surface and polymer
science; technologies, notice, not sciences, implying we
have only to apply what is already known).
It is only a little more then 100 years since Planck
resolved the ultraviolet catastrophe by postulating the
quantum nature of light. It is just 100 years since Einstein
used that to explain the photoelectric effect. It is scarcely 70
years since Goedel’s theorem, de Broglie’s wave particle
duality, quantum mechanics and the theory of the chemical
bond emerged. The scientific world turned upside down in
the first half of the 20thcentury.
It is only half a century since Watson and Crick
announced the new biology revolution. The whole scientific
world turned upside down again.
New dogmas dominate science. They are embodied for
these authors in a slide from a lecture at a Nobel
Symposium 20 years ago.
The slide said :
One would think it meant Nuclear Magnetic Resonance.
NMR Means: No More Research !
By which the preposterous lecturer meant that it was
now possible to simulate any complex chemical on a
computer and design new drugs. Cancer solved, the whole
bit. When a perceptive English biochemist asked him what
would happen to his model protein if he heated it to say37
degrees and so denatured it, the earnest NMR adept
confidently said that he would change the parameters of his
15,000 molecular force parameters.
Nor have things moved. The NMR syndrome is now
the macromolecular simulator syndrome, being endemic,
even at the 100thanniversary Nobel symposium in 2001.
There are now libraries of model proteins, gorgeous
disneyesque cartoons that purport to represent reality, with
a hundred thousand molecular potential parameters.
Yet no one can simulatec, or calculate from solution
theories the osmotic pressure of a solution of sodium
chloride. Or the strength of a "hydrogen bond"d. Nor can
one simulate the surface tension of water, or explain why
ice floats on water. [Actually one can now but not within
the conventional theories (3)].
Why should we care? After all, Allah akbar.
Galileo was persecuted by the Church not because of
his propagation of Copernican views. The Jesuit scholars
were not stupid, and accepted quietly, without any
problem, that the earth revolved around the sun. But
Galileo blotted his copybook by including in the appendix
of his book, mimicking Plato’s dialogues, a debate between
"Simplicio"-a thinly disguised Pope Urban V11, and
himself. Galileo ridiculed St. Thomas Acquinas’
Aristotelian argument that after the consecration of the host
and wine in the Mass, Christ was physically present. Abad
mistake. You can not attack the foundations of the Catholic
Church and expect no reaction.
The Vatican of modern science is represented
unwittingly today by the editors of the most cited journals,
journals with their own Orders. Like the Church before
Luther, before the Enlightenment, there shall be no
questioning of this order. But as happened for Mathematics,
cracks are beginning to appear in the edifice. It is our
purpose here to try to identify what went wrong, where the
cracks lie. And to speculate on what will become of it all.
Before we go further, it is necessary to try to be clear
about what we mean by saying that the physical and
biological sciences are conceptually disjunct. To many
people, e.g. those that can model with apparently exquisite
delicacy the transport of particular macromolecules across
pores in a membrane, and indeed the membrane itself, the
question is ridiculous. The response from such people
would be that the physical sciences, here molecular
simulations, ARE contributing to the biological sciences.
And as Maurice Wilkins was reported to have said when
someone pointed out that Rosalind Franklin’s DNA
samples were four, not two stranded, "why mess with a
good theory". So too the Ptolemaic system of the planets,
with ever increasing numbers of parameters, worked well
for hundreds of years. But if engineers tried to use it to put
a man on the moon, a feat requiring some predictability,
they would surely fail. The heliocentric Newtonian system
here has some advantages, besides being more nearly
correct. It turns out, as we shall see below, that the
foundations of the physical sciences as often applied to
biological problems are just as flawed or more so than the
Ptolemaic planetary system is for the solar system.
By a theory then we mean, as physical scientists, a
804B.W.Ninham and M.Boström
Bridges between physical and biological sciences805
predictive, encompassing, systematic dictionary of events.
A theory proper must be subject to rigorous scrutiny. For
example if we claim to predict that a protein folds in a
particular conformation at a certain concentration of
sodium chloride, then a proper theory must also predict the
conformation in any other 1:1 salt, say sodium chlorate.
And why a particular molecule turns inside out to become
a prion, if they do exist. And the same for crystallization of
the protein. Or again, if we calculate via theory the force
between membrane bilayers in Na Cl, we should be able to
calculate the same forces (ten times larger) in sodium
acetate. If we can not, then we are curve fitting and may as
well just do the experiment.
Stephen J. Gould, the famous writer on evolutionary
theories wrote, in his book Eight Little Piggies, that "I have
long argued that conceptual locks are more powerful than
factual lacks as barriers to scientific understanding".
It is a nice aphorism. What are these conceptual locks?
Surely one would think that the foundations of the physical
sciences must be correct? Not so. It turns out that just as for
mathematics itself, the foundations are shot full of holes.
This is an astonishing statement, but it happens to be true.
The first of our problems is that all simulations or
theories of chemistry relevant to biological systems, be
they water, solutions, electrolytes, proteins, membranes,
polyelectrolytes, ignore dissolved atmospheric gas.
Dissolved oxygen is about 5 x 10–3molar at 1 atmosphere
pressure. Nitrogen is about the same (Carbon dioxide adds
more complication). The solubility varies with salt and
drops to essentially zero at 1 M. These gases are at a 10
times higher concentration in oil (lipids). These annoying
components are usually completely ignored.
But we did not evolve in a gasless atmosphere. So
what? Well, it turns out that hydrophobic interactions
central to self assembly of membranes, and to interactions
between proteins and colloidal particles are much reduced
in magnitude (by factors of 10 or more) or switched off,
with removal of dissolved gas (e.g. air, oxygen, or
nitrogen) (1,21,27,39). This is hugely important practically.
But it also means that virtually all theories we have that
depend on molecular forces may not be relevant, at least
quantitatively, to the real world!
The structure of salt water is also completely different
in bulk, and at hydrophobic and hydrophilic interfaces, if it
contains dissolved gas or does not (13,14,43).
Dissolved gas may well be the source of hydrophobic
cavitation providing the driving force for enzyme action in
some cases (22). Very recent work suggests that this may
very well be the correct mechanism (17).
The language of shape: cubic phases
In studies on the statistical mechanics of self assembly
of soft condensed matter, surfactants and lipids, of
microemulsions and emulsions, the multimolecular
aggregates usually considered are limited to the perfect
Euclidean shapes of spheres (micelles), cylinders
(hexagonal phases), bilayers (vesicles, multilamellar
phases), and reversed spherical micelles. (20,30,35,42,44).
It turns out that the language of nature is much richer. The
description of the ubiquitous shapes formed by membranes
and in cell organelles is more often than not given by
hyperbolic geometries. (19). The same is true in inorganic
These, often cubic phases, called cubic because of their
rotational symmetry, are everywhere bicontinuous. A
multilayered lipid membrane can transform to a porous
honeycomb structure where the average curvature of the
bilayer is zero, but the Gaussian (product) curvature varies
continuously over the surface. The cubic phases can be
either thermodynamically equilibrium structures, or
metastable. It is natural that they should form, as the
channeling and delivery and exchange of biochemical
reactants, for example, (Mg2+vsH+in chloroplasts); would
be impossible were the membrane to be a multilamellar
stack. There are now 1000 or so of electron micrographs of
such structures from a very wide range of cells. A large
collection and identification of their crystallographic
symmetries by T. Landh is in the book The Language of
Shape(19). With pure lipids and surfactants in water, cubic
phases are equilibrium structures with pore dimensions of
the order of the size of the lipids, about 13 Å. In cells
cubosomes often have pore sizes of the order of 1300 Å.
They form probably as a consequence of Le Chatelier’s
principle, a 3-dimensional analogue of Gibbs Marangoni
hydrodynamic phenomena well known in two dimensions.
Opposing diffusion gradients of reactants and energy are
both the source and sink of the organizing principle.
The classic conceptual lock occurred in medicine.
Descartes might have said: "I breathe, therefore I am".
Because without breathing his capacity to contemplate
almighty God would have been limited. Until very
recently, 5 years ago, all the literature on lung alveolar
structure held it to be a monolayer. The fact was that this
model could in no way physically explain how the lungs
operated at essentially zero tension, and exchanged oxygen
with carbon dioxide and water. This perturbed researchers
not at all. It was surreal, rather like our knowledge of
circulation of the blood prior to Harvey. Can modern
medicine really be so limited? The correct structure, a
bicontinuous cubic-like phase was revealed by careful
cryo-transmission electron microscopy. From this correct
structure one could understand the system and use that
knowledge to design better artificial lung surfactants (25).
Supra-self assembled states, with cubic phases
surrounded by a few protecting bilayers, occur as natural
states with surfactants and microemulsions. Such
inhomogenous objects occur because any topologically
closed container has a physico- chemical environment
different inside and outside. The different environments in
which different driving forces are operating lead to the
inhomogeneous state of self assembly (20,30,35,42,44).
Such cubosomes surrounded by bilayers are responsible
for "vesicles" that transport calcium across synapses.
Just as three dimensional cubic phases are now
understood to be natural and everywhere, so to it is likely
that 2 dimensional analogues called mesh phases occur in
nature. Lipids can self assemble into not just bilayers but
bilayers with holes or meshes. These can accommodate the
proteins. A number of such self assembled equilbrium
structures now exist. If we are allowed to be speculative,
conduction of the action potential along the nerve
membrane would involve cooperative phase changes that
couple the lipid phase changes from the mesh phases to
ordinary bilayers with the transmembrane ion transport.
Such a process would explain general anaesthesia via
hydrophobic gases like hydrofluorane. General anaesthesia
is not remotely understood. The very hydrophobic gas has
to partition into the oil-like interior of the membrane
bilayers of cells, in so doing changes curvature and induces
a too strong change in state to a mesh phase. The effect is
surely physical, no real chemistry involved and it must
involve temporary changes in the membrane structure. (As
early as 1959, Pauling proposed a physical explanation for
anaesthesia. It is attributed to the formation in the brain of
minute hydrate crystals of clathrate type (40), but if this is
true or not is still uncertain. It is not known if Argon goes
into the membrane or forms clathrate at the membrane
surface. Argon, Xenon and Krypton have anesthetic
properties, Pauling attributed this to their capacity to form
hydrates (chlathrates) due to their high apolar character.
What is interesting too, is that nitrogen, which is only
weakly apolar under the atmospheric pressure can form
hydrates under higher pressures (according to theprinciple
of Le Chatelier, because water in hydrates is more dense
than 1) and then is responsible for the divers’ narcosis).
The point is that with a conceptual lock for membrane
structure limited to ordinary Danielli-Davson bilayers, one
is unlikely to find a testable rationale for this kind of
anaesthesia. (Exposure of multilamellar liposomes of
phosphatidylcholine to hydrofluorane gas induces an
immediate transition to a lipid cubic phase). The same
process would be responsible for the apparently permanent
brain damage caused by petrol sniffing of octane or gassing
with CO2. Local anaesthesia with cationic drugs like
lidocaine is easily explained by conventional ideas.
The existence of mesh phases can also explain why it is
that bacteria in the mouth and others like pseudomonas
become immune to cationic surfactants. These are
routinely used in all household products and in hospitals
sterilising agents. Above the critical micelle concentration
(CMC), they disrupt cell membranes. Below the CMC,
these surfactants are potent immunosuppressants for
reasons solely physico- chemical, that are as understood as
they are completely ignored (3,4).
Bacteria that become immune to cationics could do so
by mutating to take on a modified mesh membrane that
actually needs the surfactant in order to survive! Again
removal of a conceptual lock on bilayer structure at least
allows a strategy to be developed to attempt a solution to
an apparently insoluble problem.
The conceptual locks above are, in the language of
football, spectacular own goals. How the entire scientific
community could ignore the effects of dissolved
atmospheric gas on the molecular forces that drive self
assembly is incomprensible. After the fact, neglect of the
biologically ubiquitous bicontinous or cubic phases is
almost as mysterious. Both have enormous ramifications.
The situation can only be understood with a religious
Henry II of England went to Rocamadour to do
penance for the murder of Archbishop Thomas a’Beckett.
His penance was to traverse the 14 stations of the Cross on
his knees. The pilgrimage site on the steep banks of the
Dordogne river has many stairs from bottom to top.
Anyone doing such penance, or not, can see that each stair
is full of fossils. Millions did the pilgrimage each year for
a thousand years. Yet the possibility that the fossils
represented the remains of real animals and that the earth
might be older than Bishop Ushur’s biblical projection
occurred to no one until almost Darwin’s time. Or if they
voiced such suspicions they were laughed out of court.
Hofmeister and molecular forces
The third of our conceptual locks, and probably the
most serious has to do with specific ion effects missing
from classical theories. These were discovered in the 1880s
in a series of elegant simple experiments by Franz
Hofmeister. As we have written elsewhere (24,38): "The
phenomena remain ubiquitous in physical and
biochemistry, and are as important in the scheme of things
as was Mendel’s work in genetics".
Hofmeister effects or sequences refer to the relative
effectiveness of anions or cations, on a wide range of
phenomena. They remain unexplained by present theories
of physical chemistry or colloid science. They run the
gammut from solubility of salts, to electrolyte activities,
surface tensions to ion exchange resins, pH measurements,
zeta potentials, buffers, micellar cmcs, microemulsion
microstructure, cloud points of non ionic surfactants, ion
binding to micelles, proteins and membranes, transport
806 B.W.Ninham and M.Boström
Bridges between physical and biological sciences807
across membranes, gel-coagel transitions, molecular forces
and colloid stability. They occur in complicated systems, in
water retention by wool, in ordinary and restriction enzyme
(17,22), and other enzyme activities (41), and in bacterial
growth (26). Although not widely recognized, precipitation
of inorganic nanoparticles, and zeolites, their morphology,
size and structure depend critically on Hofmeister effects.
Even the simplest problem of all, gas bubble-bubble
interactions (15) and their dramatic dependence on the
nature of cations or anions remains a mystery. The effects
are attributed to and subsumed under different names in
what is now a veritable zoo of "new forces": hydration
forces, specific pi electron-cation interactions, ionic
bonding, hydrogen bonding, hydrophobic forces, and so on.
In the end these come back to the original effects studied by
Hofmeister, electrolyte, surface, and macromolecular and
other solute induced water structure, and vv.
From one point of view, apart from the tantalizing hints
provided by the ubiquitous Hofmeister fingerprints, the
lack of any systematics in phenomena dealing with
electrolytes is not a concern. We are used to thinking that
all of chemistry and especially biochemistry and molecular
biology, is specific. And certainly most scientists in the new
biological sciences consider it so. They have enough
concerns of their own not to be bothered with the subtleties
of theories which seem irrelevant. But if it is all specific
then no systematics like Hofmeister series would exist.
And the fact remains that nearly all conceptualization of
phenomena the biologists have to deal with do depend on
basic theories of solution and colloid chemistry and
molecular forces. This is so both for the interpretation of
measurements, and for the intuition that underlies
experimental design. Ideas at the foundations of
physiology, like proton and ion pumps across membranes,
are derived from the theory of the electrical double layer.
Simulations that "confirm" such intuitions are tautological.
Measurements, of ion binding, or pKas, or pH, of self
assembly of surfactants and lipids all depend on
electrostatic theories that we know are seriously deficient
and lack predictive capacity. The result is that the barriers
between the physical and biological sciences remain.
Equally, and even somewhat more alarming, chemical
engineers and chemists in the real world know that apart
from a good book on Gibbs’phase rules, nearly all they are
taught is useless, and misleading. In the end a phlogiston
theory can go so far and then no further.
The inclusion of specific ion effects correctly in a
predictive dictionary of events that we call a theory is a
central task of chemistry today. It was not possible in
There has been some progress. Recent work has shown
that simplified theories, of electrolyte solutions and their
interfacial tensions, and of colloid stability, are all
fundamentally flawed (35).
Many of these issues are addressed in the papers
contained in Ref. (24,38).
A large number have been written by the present
authors recently and we refer the reader to those papers,
and to (24,38) for information on the present state of affairs
(see also other papers of the special journal issue of Ref.
(24) devoted to the Hofmeister effect). Suffice it to say here
that the whole business is undergoing a massive shake-out.
Even the interpretation of measurements on pH, pKas, and
buffers, besides electrochemistry generally have to be and
are being revised. All depend substantially on specific ion
effects (and dissolved gas), that previous theories do not
Where did we go wrong? The matter is highly
technical. It can be seen by considering the prototype
problem of Colloid Science, the interaction forces of two
molecularly smooth particles across salt water. The nature
and strength of these forces determines the stability of a
colloidal suspension against flocculation. The theory is
named the DLVO theory after Deryaguin, Landau, Verwey
and Overbeek, and was the core of colloid and liquid
surface science for more than 50 years. It makes the ansatz
that the forces acting are of two kinds, and that can be
considered separately. The one is electrostatic, treated by
the (non-linear) electrical double layer. The other,
attractive, forces are quantum mechanical in origin. They
are many body forces in no way accessible by two and
three body molecular forces. But they can be accessed by
Lifshitz theoryewhich purports to be a complete quantum
electrodynamic solution of the many body interaction
problem. But it is only a linear approximation. The net
result is that the combined theory, which treats half the
forces in a nonlinear theory and the other half in a linear
theory, violates two fundamental principles –the Gibbs
adsorption isotherm and the gauge condition on the
electromagnetic field– charge current conservation (35).
So the theory does not work. It misses all specific ion
effects, and where agreement between theory and
experiment is claimed, either curve fitting or poor eyesight
are generally to blame, or else the wish being father to the
thought. (Deryaguin and Overbeek, inventors of the theory,
did not claim it worked at the high salt concentrations
appropriate to biology. Indeed Deryaguin taught his
students that it failed above 0.01 M and did not know why).
Nevertheless there is much progress in sorting out this mess.
The confusion spreads out equally to theories of
electrolytes (Debye-Huckel and modifications thereof) to
interfacial tensions (9,11), to interpretation of pH (7,8) and
membrane potentials (12), to the Born free energy of
transport of an ion across membranes (6). In all these
problems one gets the electrostatics right, even including
the hydration due to charge, but ignores the specific ion
effects due to the other half of the problem, the ignored or
incorrectly treated electrodynamic forces.
Once again, how we came to this unpretty state of
affairs is incomprehensible. These matters are being
In essence, we can adduce that the reason the physical
sciences have not contributed to modern biology is that
they have not contributed to themselves!
Conceptual locks in physics and biology
Lest we imagine that all the problems can be assigned
to us benighted physical chemists, we have to remark that
the physicists are equally culpable. It had been thought that
Lifshitz theory of interactions, a triumph of modern mid-
century physics, represented a complete solution of the
quantum mechanical many body problem. It does not. At a
certain point in its mathematical derivation, the theory goes
through a magic mirror and smoke routine and a sleight of
hand that means it collapses to a semi classical theory. See
(35,28) and the appendix to Ref. (24).
It is worse than that. Even the classical derivation of the
famous Casimir Polder "retarded" interaction between two
atoms is just plain wrong, being correct only at zero
That might be considered an idle curiosity, with no
intersection with biology. But the related problem of
photon transfer between an excited state molecule and one
in the ground state is of paramount interest, in
photosynthesis. Here again the long range form of the
Förster, or the resonance, interaction potential is not even
right at zero temperature.
At any finite temperature the classical 50 year old
textbook result is quite wrong (10)!
Direct role for physics in biology? The theories used to
interpret photon and electron transfer in biological
molecules are at the same level as the DLVO theory. The
two processes, photon transfer and electron transfer are
coupled and can not be treated separately. Long range
infrared photon transfer between pheromone molecules
emitted in a metastable state and protein receptors on the
insect antenna are probably the mechanism for
communication via pheromones. While the sequence of
biochemical and neurophysiological events consequent on
recognition of a pheromone is well understood, the
recognition process is not. All pheromones are simple, non-
ionic, non-reactive hydrophobic molecules. Typically they
are short e.g. C12 hydrocarbons, with a simple terminal or
medial group, such as aldehydes, alcohols and acetates.
They differ, in the nature of this group, and position of an
occasional double bond. The emitted pheromone plume
from the female often consists of two or more compounds.
For the pheromonal communication system to be effective,
the male has to be able to single out the specific pheromone
blend from other blends emitted by different species. Odor
discrimination is accomplished by the sensitive olfactory
system, which is primarily located in the insect antennae.
Recognition of the pheromone molecule is supposed to
proceed as follows: The hydrophobic pheromone is
physisorbed via van der Waals forces on the solid
hydrophobic antennae. The adsorbed pheromone then
diffuses along the surface until it finds a molecular sized
pore tubule containing an aqueous sensillar lymph
protecting the sensitive olfactory neurons. The sensillar
lymph contains a highly abundant protein that specifically
binds to pheromones, thereby facilitating the transport of
the hydrophobic odor molecules through the aqueous
lymph to the receptor at the dendritic membrane. Upon
reaching the receptor site, either the pheromone molecule
alone or the pheromone-protein complex activates the
receptor, which give rise to action potentials that in turn
elicit a behavioral response. For the olfactory system to be
effective, it is of great importance that the pheromone
molecules are rapidly eliminated to maintain high
sensitivity towards additional pheromones. It has been
shown that little desorption takes place on the antennae
which indicates that most of the adsorbed pheromones
enter the sensillum as well as that the desorption process
can be ruled out as a mechanism of removal and
inactivation of the odor molecules. This also implies that all
the molecules adsorbed on the antennae are degraded in the
sensillar lymph. It has been suggested that the pheromone
binding proteins as well as certain enzymes might be
involved in the inactivation and degradation of the
This hypothesis can not be correct. There is nothing
specifically different in the visible or ultra-violet spectrum
of all pheromone molecules that determine the nature of
the van der Waals forces. There can be no discrimination in
adsorption, surface diffusion or protein-pheromone
interaction. Further, every other hydrophobic molecule in
the atmosphere, present in billions of times larger
concentrations would also bind to the antenna with the
same van der Waals forces. The antenna of the unfortunate
male insect would be coated with a thick film of all these
other molecules. This would effectively prevent detection
of the relevant pheromones emitted by the female insect.
There is an additional well-known objection. The
proposed van der Waals interaction is far to weak and far to
short-ranged to account for recognition of the extremely
low concentrations of pheromones emitted by the female.
The mass balances simply do not add up and are missing
factors of more than 106. That conclusion from numerous
experiments is despite the fact that only a few receptor
molecules need to be activated to trigger a response. Some
other much longer ranged specific communication must be
In seeking other possible explanations we remark that
no chemical reaction between pheromone and receptor
protein seems to be involved. Since van der Waals forces,
due to molecular polarisabilities in the visible and
808 B.W.Ninham and M.Boström
ultraviolet are non-specific and too short ranged, we
consider the infrared region. Here certainly the pheromone
molecules differ substantially. In the infrared the response
functions are indeed highly specific. We then propose that
a pheromone is emitted by the female in a long-lived
metastable excited state. The pheromone may also be
excited into this long-lived metastable excited state by
sunlight. The vibration modes of the protein receptor
molecule in different conformations, again in the infrared,
are also highly specific. If the energy of one of these
excited states coincides with that of the metastable
pheromone, then energy transfer can take place through
photon exchange via the quantum mechanical resonance
energy mechanism (10). This interaction between an
excited and ground state molecule is stronger, of longer
range, highly directional, and most importantly highly
specific. At distances large compared to molecular scales
of van der Waals interaction we can envisage a process
whereby the pheromone molecule in its metastable excited
state identifies an identical resonance frequency in the
protein receptor and transfers a photon of precisely the
right energy to induce the required conformational change.
This interaction does not require that the pheromone
actually come into physical contact to activate the receptor
protein. The conformation change so induced allows the
receptor protein to be released. Pheromones certainly will
have resonances in the IR. Some must coincide with those
in the IR spectra of candles. Which might explain the fatal
attraction of moths to candle flames and the frequently
observed mass immolation of insects attracted to
Australian bush fires. Further, insects are not too much
engaged in mating when the atmosphere is moist –water is
a very strong infrared adsorber and likely to de-excite the
pheromone molecules. As further hint that such a physical,
as opposed to chemical mechanism might be involved we
note too that fireflies evidently communicate in the visible
region, but the emission spectrum must contain a weak
contribution from the infrared. One can test this hypothesis
by experiment as follows. Isolation of male insects in a
closed container with an infrared window and exposure to
a very weak tuneable infrared laser source either evinces a
response or does not. Estimates of an appropriate range of
frequencies for particular pheromone molecules might be
obtained via quantum chemistry calculations. To suggest
that this be tested as the only plausible mechanism so far,
will cause apoplexy to entomologists who know no
Consequences of using flawed theories
– pH: The determination of pH is a matter prescribed
by an International Union (IUPAC). The measurements
these days are done with typically a glass electrode. If pH
is fixed with a buffer and the pH of the solution measured
as a function of salt concentration, apparent pH changes
with salt and follows a Hofmeister series. (So in fact do
activity coefficients). The variation can be as much as a
whole pH unit, which is significant. The theory used to
interpret the measured surface electrochemical potential
from which the pH is deduced is purely electrostatic. Any
changes in pH with salt, salt type, proteins, polyelectrolyte,
are attributed to bulk electrolyte activities. The standard
theory ignores any adsorption of anions and cations at the
glass electrode due to electrodynamic (dispersion) forces,
as for the DLVO theory. In fact the entire effect can be
estimated and assigned to this missing surface adsorption
alone! With a different buffer, and the same supposed pH,
the effect can be reversed (7,8). So we do not know what
pH we really have. The result is that all assumed pKa’s for
proteins that depend on salt concentration and ionic species
may well be in error!
– Ion binding: The measurement of ion binding, e.g.
Ca2+to micelles or membranes or polyelectrolytes is
usually done via NMR. Again the interpretation of the
measurement requires a theory. The "theory" used is
apparently phenomenological. But it can be shown (31,32)
that this is exactly equivalent to an electrostatic double
layer model which gives the phenomenological theory as a
special limiting case. (The same comment applies to the
Manning theory of counterion condensation on
polyelectrolyes). Since it is missing a major component,
the ion specific, dispersion or Hofmeister forces, the
interpretation of the measurements which yield ion binding
parameters is wrong.
– Ion transport: A similar situation occurs with
transport of ions across a lipid membrane (6). The usual
theory derives from the Born electrostatic self energy of an
ion, which depends on the dielectric constant of the media
(water-oil) involved. But there is a significant contribution
due to the missing dispersion –electrodynamic fluctuation–
elf energies. This is important too for solubilities. Again for
transport across real pores in a membrane (Na+, K+, Ca2+)
it is often assumed that the anions are irrelevant except to
contribute to bulk activities because the membrane is
negatively charged. But again the anions (and cations) do
experience over-riding dispersion forces that are ion
specific and are involved in the real, not model, transport
process. This has a bearing on the meaning of ion pumps,
in particular, the Mitchell proton pump, based on what is
essentially the double layer theory. These matters are
equally serious for electrochemistry.
– Red cell: The concentrations of ions inside and
outside a red cell, are very different. The cell fluid has huge
amount of potassium and magnesium ions. There are only
low concentrations of these ions in the blood plasma where
it instead is large concentration of sodium ions.
It is not clear, given the matters raised above that this
can be attributed entirely to some magical pumps. At least
the level of proteins inside the cell is very high, with high
Bridges between physical and biological sciences809
surface area, the partitioning of ions between the finite
external reservoir and that inside cells should indeed be ion
specific. This is supported by the fact that exchange of
chloride to salicylate ions can reverse the permeability of
ions across a cell membrane. How much this Hofmester
contribution could be has not yet been estimated. The same
effect would occur with cells of the nervous system.
– Enzymatic catalysis: Given the abundance of
enzymes, it might be thought that the physical scientists
might have some to say on enzymatic activity. The
attachment via weak physical forces of enzyme and
substrate is at least an order of magnitude too low to
provide enough energy. Where might the energy come
from. Subcritical hydrophobic cavitation in the active site
cavity that depends on dissolved gas is one plausible
mechanism for restriction enzymes,and presumably for
many others (17,22). For others it is not so clear. For
example, with horseradish peroxidase, the "active site" is
just not known. There may well be NO active site. This
enzyme and many others are very large. That should
provide a lead. It does, and again this is directly connected
to the missing dispersion-Hofmeister forces, and self
energies. To see this, consider the problem of cracking of
oils by zeolites. These are molecular silica framework
sieves. The energy to do so, say to cut hexadecane to
decane and hexane, comes from adsorption of the
hexadecane into the pores of the framework by dispersion
forces. The change in self energy of the molecule due to its
adsorption is such that it essentially shakes itself to bits, to a
lower energy state comprising the two fragments (5). The
same physical process could be involved in the ATP-ADP-
H+reactions, catalysed via the favourable dispersion
energies due to interaction with the large enzyme "surface".
Maybe. Maybe not. But in the absence of any other
explanation for the source of the energy, we are sticking to it.
THE BIGGER PICTURE:
CLIMATE CHANGE AND ALLTHATJAZZ
Evolution and the bubbles
Stephen J. Gould wrote a great deal on the Burgess
Shales extinctions of the early Cambrian. Why so many
flourishing phyla, 24, suddenly disappeared with only a
miserable few that became us, about 4, is a mystery. As
indeed was the apparently complete extinction of their
predecessors in the Ediacara fauna, the first multicelled life
forms. In his attempts to rescue an increasingly modified
Darwinism, Gould invented the concept of contingency in
evolution. Suppose, he says, one could play the tape of the
evolutionary tape backwards, and start again. The next
time round a totally different set of phyla would inherit the
earth. Entirely a matter of contingency, an accident.
That view implies a profoundly pessimistic philosophy.
Because it implies that there is no hope. Yet it is not
necessarily so. Consider the bubbles (15). Whatever the
ultimate reasons that depend on molecular forcesfthe
phenomenon exists. In the Burgesss Shales and in several
other major extinctions, like the Permian, the salt
concentration in the seas where life existed dropped below
the critical optimal level of 0.15 M (the optimal
concentration is 0.9% NaCl (about 0.15 M) in the
mammals and birds that emerged in the Permian or just
previously, but only 0.6% in all the other Vertebrates. In the
Invertebrates, it can be higher than 0.15 M). This is because
the preceding ice ages removed massive amounts of water.
A consequence was precipitation of massive salt beds.
When the ice melted one can envisage a situation like the
Baltic Sea, with salt concentration below 0.15 M. The
result is that many plankton, the first stage in the food
chain, die. (This is known: they died of diver’s disease, the
bends, due to bubble nucleation and fusion in hydrophobic
organelles in their cells. This does not occur for higher salt
Fantastic or false, the argument shows that contingency
is not yet necessarily the answer.
A great deal of grant-application – driven work has
gone over the past few years into so called microfossils.
These are from rocks of great age, discovered first near
Marble Bar in Western Australia. They appear to be precise
replicas in miniature of much larger small fossil shells.
Mars microfossils are too small to be microfossils. The
ones from Marble Bar are of the right size region but still
not microfossils (18). Their age – 3 or so billion years - is
about twice or more of the earliest previously known life
forms. That has huge consequences for our expectations on
the nature of the early Earth atmosphere. And flowing on
from that, of our expectations on climate change. Of
singular further interest was the discovery of such
microfossils in a meteorite from Mars found in Antarctica.
This suggested that life occurred on Mars, maybe before
us. The implications are immense. Regrettably it turns out
that exactly the same diversity of such microfossils can be
made in the lab by simple precipitation experiments. These
take about a day (6). Astrobiologists are undeterred.
One of the first discoveries of "life-from-space‘ was
made by a student in one of the author’s own university. A
visiting Professor to BWN’s Department had a piece of a
chondoraceous meteorite that arrived from Mars on a farm
in Victoria. The farmer sold it to NASAillegally. The idea
was to extract carbonaceous material from this meteorite,
characterize its properties using Langmuir Blodgett
techniques of surface chemistry to see if it contained any
life-forming molecules. It did, the result publicized to great
fanfare! The American professor departed happily. Shortly
after the Australian hosts got access to a missing surface
810 B.W.Ninham and M.Boström
infrared spectrometer to push the work further. Alas. The
spectrum of the outer space life forming molecules was
exactly that of bovine serum albumin. The conclusion is
inevitable. Either there are cows flying around in space or
the meteorite landed on a cowpad in the field. Sic transit
From a different perspective Gould is surely correct in
his views on contingency. The sun ultimately is the arbiter
of all, and the massive climate changes that led to the
geological record in a relatively short time frame can only
be due to fluctuations in the sun’s magnetic field, and
consequent solar wind. Or real changes in direct energy
output from the sun. The little ice ages after 1000 AD can
have had no input from mankind. Nor those of the last
Yet the present theory of the sun, the standard solar
model, in no way explains the Sun’s magnetic field.
Astrophysicists’view of the earth’s early atmosphere is
diametrically opposed to that of the Geochemists. It is an
important matter. Either we are running out of CO2or we
have too much. Some skepticism on such science is
The sun’s magnetic field seems to have now been
explained, and the standard solar model discredited. It
seems the sun is the residue of a supernova explosion, the
view held and later dismissed long ago. The arguments are
based on very careful accumulation of elemental
abundances in the solar system obtained over 40 years
from space probes (29).
It is much the same story all over again. The present
theories of nuclear forces supposed to fuel the sun and of
apparently missing neutrinos invented as joke by Fermi
and now taken seriously has the same problems as our
DLVO theory (34). We leave this matter because as the
Romans said: hic sunt leones. The point is that even in the
established senior sciences we have some problems to
To the outsider, the areas of science with which we have
been concerned, at the boundaries of the biological and
physical sciences, seem well and even flourishing.
As the Cat in the Hat, of Dr. Zeuss fame, puts it:
Many mumbling mice,
Making midnight music,
In the moonlight,
The music is a bit out of tune.
It might be thought that the problems that face us are
nothing more than a matter of style, approaches to science
attributed to Aristotle, unfairly, or to Galileo. But some of
our conceptual locks can not be dismissed. Dissolved gas,
bicontinuous geometries and cubic phases, supra self
assembly, Hofmeister effects in molecular forces, the flaws
in text book theories on matters as fundamental as pH and
buffers and electrochemistry come as shock at first
exposure. It is not a matter of taste, hypothesis or even
These are matters of fact that, once we recognize them,
can no longer be swept under the carpet. The identification
of a problem is the first stage in its solution, so there is a
Let us finish now on a less strident note, and borrow
from wiser predecessors:
From Morris Kline in his peroration on the plight of
It behooves us therefore to learn why, despite its uncertain
foundations and despite the conflicting theories of
mathematics, mathematics has proved to be so incredibly
successful. So too for science.
And from his translation of some aphorisms of
Xenophanes that seem to be apposite:
The Gods have not revealed all things from the beginning,
But men seek and so find out better in time.
Let us suppose these things are like the truth.
But surely no man knows or will ever know
The truth about the gods and all I speak of.
For even if he happens to tell the perfect truth,
He does not know it, but appearance is
fashioned over everything.
There are rapid strides being made to improve and
remedy present theories. And what is encouraging is that
when the chemistry is done correctly, when the conceptual
locks are removed, more often than not the emerging
theories do actually work, predictively!
Acknowledgments – Mathias Boström thanks the Swedish Research
Council for financial support. We are deeply grateful towards our editors
Pascale Mentré and Yolène Thomas for helping us improve this paper. We
are grateful for critical reading to Stephen Hyde, Peter Stewart, Veronica
Ninham, Giles Pickford, John Molony, and others of our lay friends that
convinced us that it is possible to communicate science in non technical
aThe theorem more or less says that:
Given any set off axioms, and a set of rules to manipulate them, i.e., a logic
of which mathematics is one of many. Then: it is possible to prove that
there are acceptable propositions, questions, within the logic, the truth of
which it is impossible to determine. Some things are unknowable, so the
idea of absolute proof falls to the ground.
bReductionists: The word means exactly what I mean it to mean, neither
more nor less, as the Red Queen said to Alice, in Wonderland.
Exemplars to us are Kepler and Newton. For them, perhaps not for James
Clerk Maxwell, the subsuming of a vast panoply of phenomena into a few
simple laws revealed the fingerprints of God.
Bridges between physical and biological sciences811
This corollary is not necessary. Nonetheless it is arguable that much of
science in the heyday of mathematics that followed the Age of Faith,
derived unconsciously from a Western, Christian view of the world, that
good will eventually triumph over evil. The physicists continue to
theologise. Witness the Big Bang theory.
The present time, the age of biology, is dominated by dogmatic
Darwinism. Darwin’s writings are so prolix that it is impossible to find
out what he really thought. Like St Paul and Christianity we have to rely
on Darwin’s champions who seem to have extracted from his writings a
content- free tautology. This is consistent with a Grecian, pagan view of
history which is tragic because it was subject to transience and destiny.
Darwin was probably clinically depressed due to his illness, and the loss
of his favourite daughter Annie. It should not be surprising then if his
writings reflected a mood to which an amoral, "survival of the fittest"
attitude could be misattributed. This is antithetical to the previous belief
in self sufficient progress. But in what we might term the Age of
Unreason, it is in concert with socioeconomic views consistent with
modern capitalism. Fortunately scientific theories, like civilizations, are
cThis statement may seem to be too perjorative.
The word "simulation" has come to take on a multitude of shades, like
"love" in the English language. It lacks the subtlety of the French. Good
simulation, like studies on the packings of objects, can reveal much
about, say molecular order and liquid structure. It is essentially an
experiment. The loss of mathematical skills in classical analysis means
that scientists generally now have no idea of how to extract a meaningful
asymptotic result that encapsulates the essence of a phenomenon from a
model; nor even what a physically acceptable model is.
dThe idea of a hydrogen bond derives from a quantum perturbation
calculation for two water molecules and is used with gay abandon. But
the universe of solutions or of DNA comprises more than two water
molecules, and a hydrogen bond, if it exists at all, has never been
quantified precisely to within a factor of 10, immeasurably small, up to
eDespite its deficiencies Lifschitz theory DOES represent a very great
advance. One can actually access say the force between proteins in
solution, or between a protein and membrane. It does so via the
measured dielectric susceptibility of a solution as a function of
electromagnetic frequency (28). This includes all many body
interactions. The clamor of the Boeotians that a protein is not a sphere,
and how can one speak of the surface of such a sphere? –and hence one
must simulate the entire complex set of molecules– is, well,
characteristic of Boeotians. No amount of explanation can satisfy such
people as the Athenians knew.
fProbably the reason for the mysterious bubble-bubble specific ion
effect is, in the end, simple. It is much as the long range hydrophobic
interaction. Without dissolved gas or other sparingly soluble solutes its
range is a maximum about 6 water molecules. This is what any
simulation of surface induced hydration or statistical mechanical
calculation would give. The interaction is due to subcritical
fluctuations in the water separating the two objects. These
fluctuations, so to speak dynamic "cracks" joining the surfaces are
only about 1/10 of Ångstrom in thickness. Dissolved gas molecules
are just far enough apart to act as intermediate surfaces that propagate
the cracks and extend the range of the forces. This is a dimensional
argument and therefore hard to dispute (45). With bubble- bubble
forces the same now critical fluctuations occur, mediated by dissolved
gas. But with salt (at 0.15 M the salt molecules are only about 18 Å
apart) the particular hydration associated with a given ion paircan
enhance or oppose the fluctuations.
1. Alfridsson, M., Ninham, B.W. and Wall, S., Role of cooions and
atmospheric gas in colloid interaction. Langmuir 2000, 16: 10087-
Andersson, S. and Ninham, B.W., Why ice floats on water. Solid
State Sciences2003, 5: 683-693.
Ashman, R.B. and Ninham, B.W., Immunosuppressive effects of
cationic vesicles.Mol. Immunol.1985, 22: 609-612.
Ashman, R.B., Blanden, R.V. and Ninham, B.W., The interaction of
amphiphilic aggregates with cells of the immune system.
Immunology Today1986, 7: 278-283.
Blum, Z., Hyde, S.T. and Ninham, B.W., Adsorption in zeolites,
dispersion self energy and Gaussian curvature. J. Phys. Chem. 1993,
Boström M. and Ninham, B.W., Energy of an ion crossing a low
dielectric membrane: the role of dispersion self-free energy. Biophys.
Chem. 2005, 114: 95-101.
Boström, M., Craig, V.S.J., Albion, R., Williams, D.R.M. and
Ninham, B.W., Hofmeister effects in pH measurements: the role of
added salt and co-ions. J. Phys. Chem. B2003, 107: 2875.
Boström, M., Fratini, E., Lonetti, B., Baglioni, P., Pinna, M.C., Salis,
A., Monduzzi, M. and. Ninham, B.W., Specific ion effects: Why pH
titration in buffer and protein solutions follow a Hofmeister series. J.
Phys. Chem. B2005, submitted.
Boström, M., Kunz, W. and Ninham, B.W., Hofmeister effects in
surface tension of aqueous electrolyte solution. Langmuir 2005, 21:
10. Bostrom, M., Longdell, J.J., Mitchell, D.J. and Ninham, B.W.,
Resonance interaction between one excited and one ground state
atom. Eur. Phys. J. D2003, 22: 47-52.
11. Boström, M., Williams, D.R.M. and Ninham, B.W., Surface tension
of electrolytes: Specific ion effects explained by dispersion forces.
Langmuir2001, 17: 4475-4478.
12. Boström, M., Williams, D.R.M., Stewart, P.R. and Ninham, B.W.,
Hofmeister effects in membrane biology: the role of ionic dispersion
potentials. Phys. Rev. E2003, 68: 041902.
13. Bunkin, N.F., Kochergin, A.V., Lobeyev, A.V., Ninham, B.W. and
Vinogradova, O.I., Existence in polar liquids of charged
submicrobubble clusters as revealed by correlation between optical
cavitation and electric conductivity. Colloids Surfaces A:
Physicochem. Eng. Aspects1996, 110: 207-212.
14. Bunkin, N.F., Kiseleva, O.A, Lobeyev, A.V., Movchan, T.G.,
Ninham, B.W. and Vinogradova, O.I., Effects of salts and dissolved
gas on optical cavitation near hydrophobic and hydrophilic surfaces.
Langmuir1997, 13: 3024-3028.
15. Craig, V.S.J., Ninham, B.W. and Pashley, R.M., The effect of
electrolytes on bubble coalescence in water. J. Phys. Chem.1993, 97:
16. d’Arcy Thompson, In: On Growth and Form, Cambridge University
17. Flannigan, D.J. and Suslick, K.S., Plasma formation and temperature
measurement during single-bubble cavitation. Nature2005, 434: 52-
18. García Ruíz, J.M., Hyde, S.T., Carnerup, A.M., Christy, A.G., Van
Kranendonk, M.J. and Welham, N.J., Self-assembled silica-
carbonate structures and detection of ancient microfossils Science
2003, 302: 1194-1197.
19. Hyde, S., Andersson, S., Larsson, K., Blum, Z., Landh, T., Lidin, S.
and Ninham, B.W., In: The Language of Shape, Elsevier Science,
20. Israelachvili, J.N., Mitchell, D.J. and Ninham, B.W., Theory of self-
assembly of hydrocarbon ampliphiles into micelles and bilayers. J.
Chem. Soc. Faraday Trans. II1976, 72: 1525-1568.
812 B.W.Ninham and M.Boström
21. Karaman, M.E., Ninham, B.W. and Pashley, R.M., Effects of
dissolved gas on emulsions, emulsion polymerisation andsurfactant
aggregation.J. Phys. Chem.1996, 100: 15503-15507.
22. Kim, H.-K., Tuite, E., Nordén, B. and Ninham, B.W., Co-ion
dependence of DNA nuclease activity suggests hydrophobic
cavitation as a potential source of activation energy. Eur. Phys. J.E
Soft Matter2001, 4: 411-417.
23. Kline M., In: Mathematics: The Loss of Certainty, Oxford University
Press, NewYork, 1980, ISBN 0-19-502754-X.
24. Kunz, W., Lo Nostro, P. and Ninham, B.W., The present state of
affairs with Hofmeister effects. Curr. Opin. Colloid Interface Sci.
25. Larsson, M., Larsson, K., Andersson, S., Kaqkahr, J., Nylander, T.,
Wollmer, P. and Ninham, B.W., The alveolar surface structure:
transformation from a liposome-like dispersion into a tetragoan CLP
bilayer phase. J. Dispersion Sci. Technol.1999, 20: 1-12.
26. Lo Nostro, P., Ninham, B.W., Lo Nostro, A., Pesavento, G., Fratoni,
L. and Baglioni, P., Specific ion effects on the growth rates of
Staphylococcus aureus and Pseudomonas aeruginosa. Phys. Biol.
2005, 2: 1-7.
27. Maeda, N., Rosenberg, K.J., Israelachvili, J.N. and Pashley, R.M.,
Further studies on the effect of degassing on the dispersion and
stability of surfactant-free emulsions. Langmuir 2004, 20: 3129-
28. Mahanty, J. and Ninham, B.W., In: Dispersion Forces. Acad. Press,
London, 1976, 236 p.
29. Manuel, O., Ninham, B.W. and Friberg, S., Superfluiddity in the
Solar interior: Implications for Solar eruptions and climate. J. Fusion
Energy2003, 21: 193-198.
30. Mitchell, D.J. and Ninham, B.W., Micelles, vesicles and
microemulsions. J. Chem. Soc. Faraday Trans. II 1981,77: 601-629.
31. Mitchell, D.J., Ninham, B.W. and Evans, D.F., Ion binding and
dressed micelles. J. Phys. Chem.1984, 88: 6344-6348.
32. Mohanty, U., Ninham, B.W. and Oppenheim, I., Dressed polyions,
counterions condensation, and adsorption excess in polyelectrolyte
solutions. Proc. Natl. Acad. Sci. USA1996, 93: 4342-4344.
33. Ninham, B.W., The Confederacy retreats: An appreciation of Sten
Andersson. Solid State Sciences2003, 5: 31-33.
34. Ninham, B.W. and Bostrom, M., Screened Casimir force at finite
temperatures: A possible role in nuclear interactions. Phys. Rev. A
2003, 67: 030701 (R).
35. Ninham, B.W. and Evans, D.F., The Rideal lecture: Vesicles and
molecular forces. Faraday Discussion Chemical Society 1986, 81: 1-
36. Ninham, B.W. and Daicic, J., Lifshitz theory of Casimir forces at
finite temperature. Phys. Rev. A1998, 57: 1870-1880.
37. Ninham, B.W. and Yaminsky, V.V., Ion binding and ion specificity -
The Hofmeister effect, Onsager and Lifshitz theories. Langmuir
1997, 13: 2097-2108.
38. Ninham, B.W., Physical chemistry: The loss of certainty. Progr.
Colloid Polym. Sci2002, 120:1-12.
39. Pashley, R.M., Effect of degasing on the formation and stability of
surfactant-free emulsions and fine Teflon dispersions. J. Phys. Chem.
B2003, 107: 1714-1720.
40. Paulin, L., Amolecular theory of general anaesthesia. Science1959,
41. Pinna, M.C., Salis, A., Monduzzi, M. and Ninham, B.W., Hofmeister
series: the hydrolytic activity of niger lipase depends on specific ion
effects. J. Phys. Chem. B 2005, 109: 5406-5408.
42. Radlinska, E.Z., Zemb, T.N., Dalbiez, J.P. and Ninham, B.W.,
Lamellar to vesicle transitions of highly charged bilayers. Langmuir
1993, 9: 2844-2850.
43. Vinogradova, O.I., Bunkin, N.F., Churaev, N.V., Kiseleva, O.A.,
Lobeyev, A.V. and Ninham, B.W., Submicrocavity structure of water
between hydrophobic and hydrophilic walls as revealed by optical
cavitation. J. Colloid Interface Sci. 1995, 173: 443-447.
44. Wang, K., Oradd, G., Almgren, T., Asakawa, T. and Bergenstahl, B.,
Phase behavior and phase structure of a cationic fluorosurfactant in
water. Langmuir2000, 16: 1042.
45. Yaminski, V.V. and Ninham, B.W., The hydrophobic force: The
lateral enhancement of subcriticals fluctuations. Langmuir 1993, 9:
Bridges between physical and biological sciences813
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