68 views

### Negative retention for chloride in hydrolysate filtration

I tried to fractionate proteins as a function of their size with an ultrafiltration membrane. I observed a higher concentration of chloride in my permeate than in my feed or retentate. The proteins do ...
66 views

### What happens when you mix alum with soap?

I was handling alum one day and accidentally I touched toilet soap after that. They reacted with each other and formed a rubberlike sticky substance (like dried glue on palm). I am curious what was ...
41 views

### Are chiral quasicrystals possible?

Quasicrystals are materials that have long-range atomic order but lack the translational symmetry of conventional crystals. All quasicrystalline tilings and packings I have read about thus far, whilst ...
78 views

### Efficiency of various Ewald-type schemes for the summation of electrostatic interactions

I am looking into implementation of Ewald summation techniques for a number of point charges in periodic 3D space (i.e. a molecular simulation box with periodic boundary conditions). The “mainstream” ...
69 views

### What is antisymmetric exchange? What is J-strain? Where does it come from?

I'm reading a paper1 by Sanakis, et al. that characterises the magnetic coupling in the $\ce{Fe3S4}$ clusters present in bacterial ferredoxin II and beef heart aconitase as arising through something ...
125 views

### Does the chemical in an alkaline battery make battery leaks unavoidable?

Battery leaks was an issue in the 80s and 90s, and since quality and innovation is constantly improving, I thought battery leak might be slowly going away. But I found that even nowadays, name brand ...
44 views

### How can I update a map/mesh and coordinates in a PyMol session file?

I have a PyMol session file I was using to create my figures. It contains a protein and ligand broken into several groups of atoms with a fair bit of overlap. There are also a few meshes built from ...
129 views

### What is Cβ (C-beta) deviation?

Molprobity and some other protein structure validation tools report a Cβ deviation statistic and offer plots for it (example below). Apparently if the Cβ is greater than 0.25 Å, some ...
62 views

### What are the mechanisms for capture of $\ce{As(III)}$ and $\ce{As(V)}$ by magnetite from water?

Magnetite, $\ce{Fe3O4}$ is able to capture $\ce{As(III)}$ and $\ce{As(V)}$ from drinking water through the following mechanisms. Bidentate-binuclear complex Monodentate-binuclear complex ...
113 views

### Predict XPS Spectrum of Organic Monolayers on a Semiconductor

X-ray photoelectron spectroscopy (XPS) is a particularly useful technique for examining the surfaces of all sorts of materials. Organic monolayers are particularly difficult to characterize completely ...
279 views

### How are turbostratic graphite phases formed?

Turbostratic graphite is graphite in which there is quenched rotational disalignment between adjacent graphene sheets, i.e. one sheet is rotated with respect to its neighbor. I suppose this could be ...
82 views

### Atomic structure

In the molecular orbital theory, the fact that a bonding and antibonding molecular orbitals have different energies is accompanied by the fact that the energy by which the bonding is lowered is less ...
43 views

### Do I really need 4 different water treatment systems with this water analysis?

We installed an artesian well and we had some surprises. We asked a few places around and they all told me that we needed 4 different systems to solve our water problem. I am ready to accept this fact ...