Investigating the Chemical Ordering in Quaternary Clathrate BaAlGaGe.

Recently, there has been an increased interest in quaternary clathrate systems as promising thermoelectric materials. Because of their increased complexity, however, the chemical ordering in the host framework of quaternary clathrates has not yet been comprehensively analyzed. Here, we have synthesized a prototypical quaternary type-I clathrate BaAlGaGe by Czochralski and flux methods, and we employed a combination of X-ray and neutron diffraction along with atomic scale simulations to investigate chemical ordering in this material.

Free-energy perturbation and quantum mechanical study of SAMPL4 octa-acid host-guest binding energies.

We have estimated free energies for the binding of nine cyclic carboxylate guest molecules to the octa-acid host in the SAMPL4 blind-test challenge with four different approaches. First, we used standard free-energy perturbation calculations of relative binding affinities, performed at the molecular-mechanics (MM) level with TIP3P waters, the GAFF force field, and two different sets of charges for the host and the guest, obtained either with the restrained electrostatic potential or AM1-BCC methods. Both charge sets give good and nearly identical results, with a mean absolute deviation (MAD) of 4 kJ/mol and a correlation coefficient (R (2)) of 0.

Disseminated aspergillosis treated with amphotericin B and surgery in a boy with chronic granulomatous disease.

A case of systemic infection caused by Aspergillus fumigatus in a seven-year-old boy suffering from chronic granulomatous disease is described. The fungus had infiltrated his lungs, his left foot and the popliteal and inguinal lymph nodes. Amphotericin B, 1 mg/kg daily, was given for three months via a central venous catheter, Progressive anaemia made amputation of his left leg necessary.

Comparative study of the in vitro antibacterial activity of cefoxitin, cefuroxine, and cephaloridine.

The in vitro antibacterial effects of cefoxitin, a semisynthetic cephamycin, cefuroxime, a new cephalosporin antibiotic, and cephaloridine were compared. With gram-positive bacteria, marked differences were found only in the effects against Streptococcus faecalis, where cephaloridine and cefuroxime were superior to cefoxitin. With gram-negative aerobic bacteria, cefoxitin, which is known to be more resistant to beta-lactamases from gram-negative bacteria than any cephalosporin, was found to be more effective than cefuroxime and cephaloridine against ampicillin-resistant strains of Escherichia coli and indole-positive strains of Proteus.