In 1964, Hückel method calculations ( using a simple linear combination of atomic orbitals ( LCAO ) method for the determination of electron energies of molecular orbitals of π electrons in conjugated hydrocarbon systems ) of molecules ranging in complexity from butadiene and benzene to ovalene, were generated on computers at Berkeley and Oxford.

From the known atomic mass of iron he calculated the molecular mass of hemoglobin to n × 16000 ( n = number of irons per hemoglobin, now known to be 4 ), the first determination of a protein's molecular mass.

The determination of their molecular structure by Roderick MacKinnon using X-ray crystallography won a share of the 2003 Nobel Prize in Chemistry.

The basis for determination of molecular weight according to the Staudinger method ( since replaced by the more general Mark-Houwink equation ) is the fact that relative viscosity of suspensions depends on volumetric proportion of solid particles.

* Dumas method of molecular weight determination

( Blue dextran is not recommended for Vo determination because it is heterogeneous and may give variable results ) The elution volumes of the standards are divided by the elution volume of the thyroglobulin ( Ve / Vo ) and plotted against the log of the standards ' molecular weights.

Due to the difference in size of two polymers with identical molecular weights, the absolute determination methods are, in general, more desirable.

This technique is widely used for the molecular weight determination of polysaccharides.

Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing.

It is a uniquely precise tool for the determination of molecular structure in gas phase molecules.

Jean Baptiste André Dumas ( 14 July 1800 – 10 April 1884 ) was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights ( relative atomic masses ) and molecular weights by measuring vapor densities.

Clore, " Using Xplor-NIH for NMR molecular structure determination ," Progr.

The determination and publication of the complete genome sequences of three clinical L. pneumophila isolates in 2004 paved the way for the understanding of the molecular biology of L. pneumophila in particular and Legionella in general.

The determination of molecular structure uses a multitude of experimental methods, that include X-ray diffraction, electron diffraction, many kinds of optical spectroscopy, nuclear magnetic resonance, electron spin resonance, and mass spectrometry.

He is notably known for the determination of the molecular structure of the enzyme ribonuclease in 1967.

He pioneered and developed a mathematical method that has changed the whole field of chemistry and opened a new era in research in determination of molecular structures of crystallized materials.

This is often used by chemists for the determination of average molecular weight.

* Dumas method of molecular weight determination

The number average molecular weight of a polymer can be determined by gel permeation chromatography, viscometry via the ( Mark-Houwink equation ), colligative methods such as vapor pressure osmometry, end-group determination or proton NMR.

* SHAPE ( molecular biology ), an NMR-based RNA structure determination experiment

The SPR-based biosensors can be used in determination of active concentration as well as characterization of molecular interactions in terms of both affinity and chemical kinetics.

The modern understanding why metachromasy occurs was advanced by Belgian histologist Lucien Lison, who studied it between 1933 and 1936 and ascertained its value in the quantitative determination of sulfate esters of high molecular weight.

This new database provides sharing of information between members of the science community that was not previously seen in northern blotting as it was in sequence analysis, genome determination, protein structure, etc.

Common experimental methods of structure determination include X-ray crystallography and NMR spectroscopy, both of which can produce information at atomic resolution.

Further, the set of solved structures is biased toward proteins that can be easily subjected to the conditions required in X-ray crystallography, one of the major structure determination methods.

For instance, determination of the structure of the ribosome — an enzyme that catalyzes peptide bond formation — revealed that its active site is composed entirely of RNA.

Methods for the structure determination of oligosaccharides and polysaccharides include NMR spectroscopy and methylation analysis.

The hydrogen bonding patterns may be significantly distorted, which makes an automatic determination of secondary structure difficult.

Since the tertiary structure of proteins is an important problem in biochemistry, and since structure determination is relatively difficult, protein structure prediction has been a long-standing problem.

"... progress in structure determination, for new polyborane species and for substituted boranes and carboranes, would be greatly accelerated if the nuclear magnetic resonance spectra, rather than X-ray diffraction, could be used.

Moreover the strong interaction of electrons with matter ( about 1000 times stronger than for X-rays ) allows determination of the atomic structure of extremely small volumes.

Neutron diffraction is an excellent method for structure determination, although it has been difficult to obtain intense, monochromatic beams of neutrons in sufficient quantities.

* Lecture notes on X-ray crystallography and structure determination

The quantum Hall effect also provides an extremely precise independent determination of the fine structure constant, a quantity of fundamental importance in quantum electrodynamics.

Such a method can be used to obtain the product in the form of single crystals suitable for structure determination by X-ray diffraction.

The unit cell volume ( V < sub > cell </ sub >) may be calculated from the unit cell parameters, whose determination is the first step in an X-ray crystallography experiment ( the calculation is performed automatically by the structure determination software ).

Very high purity PEG has recently been shown to be crystalline, allowing determination of a crystal structure by x-ray diffraction.

Nonetheless, bacterial expression has the advantage of easily producing large amounts of protein, which is required for X-ray crystallography or nuclear magnetic resonance experiments for structure determination.

In chemistry, MD serves as an important tool in protein structure determination and refinement using experimental tools such as X-ray crystallography and NMR.

With the earlier determination of the structure and central importance of DNA, it became clear that all proteins were being produced in some way from its genetic code, and that this step might form a key control point.

) DNA Changing Science and Society: The Darwin Lectures for 2003 CUP 2003, includes a lecture by Sir Aaron Klug on Rosalind Franklin's involvement in the determination of the structure of DNA.

Although this phenomenon may be exploited to study the magnetic domains of materials by Lorentz force microscopy, it may make crystal structure determination virtually impossible.