The Berlin Airlift

Watch the fascinating documentary “The Berlin Airlift, The Sound of Freedom”to include comments on the production and contents of the film, by Tom Cossaboom. Tom served as executive producer for the film and was responsible for the historical content and interviews. He was also the USAF Historian from 1975-2003 in both Europe and the U.S

Hook length biases for self-conjugate partitions and partitions with distinct odd parts

We establish a hook length bias between self-conjugate partitions and partitions of distinct odd parts, demonstrating that there are more hooks of fixed length $t \geq 2$ among self-conjugate partitions of $n$ than among partitions of distinct odd parts of $n$ for sufficiently large $n$. More precisely, we derive asymptotic formulas for the total number of hooks of fixed length $t$ in both classes. This resolves a conjecture of Ballantine, Burson, Craig, Folsom, and Wen.Comment: 23 page

Rescue of a genotype 4 human hepatitis E virus from cloned cDNA and characterization of intergenotypic chimeric viruses in cultured human liver cells and in pigs

Hepatitis E virus (HEV) is an important but extremely understudied human pathogen. Genotypes 1 and 2 are restricted to humans, whereas genotypes 3 and 4 are zoonotic, infecting both humans and pigs. This report describes, for the first time, the successful rescue of infectious HEV in vitro and in vivo from cloned cDNA of a genotype 4 human HEV (strain TW6196E). The complete genomic sequence of the TW6196E virus was determined and a full-length cDNA clone (pHEV-4TW) was assembled. Capped RNA transcripts from the pHEV-4TW clone were replication competent in Huh7 cells and infectious in HepG2/C3A cells. Pigs inoculated intrahepatically with capped RNA transcripts from pHEV-4TW developed an active infection, as evidenced by faecal virus shedding and seroconversion, indicating the successful rescue of infectious genotype 4 HEV and cross-species infection of pigs by a genotype 4 human HEV. To demonstrate the utility of the genotype 4 HEV infectious clone and to evaluate the potential viral determinant(s) for species tropism, four intergenotypic chimeric clones were constructed by swapping various genomic regions between genotypes 1 and 4, and genotypes 1 and 3. All four chimeric clones were replication competent in Huh7 cells, but only the two chimeras with sequences swapped between genotypes 1 and 4 human HEVs produced viruses capable of infecting HepG2/C3A cells. None of the four chimeras was able to establish a robust infection in pigs. The availability of a genotype 4 HEV infectious clone affords an opportunity to delineate the molecular mechanisms of HEV cross-species infection in the future

Identification and Characteristics of a Fungal Contaminant in Naphthenic Metal Working Fluid

Microbial contamination of metalworking fluids is an ongoing problem. The fluid provides nutrients and thus the mocrobes degrade the emulsion oil fluid. Samples were obtained from a metal fabrication factory that was experienceing intermittent contamination and fouling of machinery with the resulting biofilm. The funal contaminant was isolated and then identified by morphological characteristics based on the Saccardo System of Classification. Morphological characteristics were observed with two approaches, light and scanning electron microscopies. The fungal contaminant was identified as Penicillium. Culture tubes of naphthenic metalworking fluid were incolulated with a sterile loop of conidia. The fluid was preared as one part oil to six parts sterile municipal water for incubation periods, 2, 3, 4, and 5 weeks at 23 degrees Celcius and 37 degrees Celcius. The interaction between the metalworking fluid and fungal contaminant was characterized by gas chromatography. The gas chromatograph curves were digitized into area sthat corresponded to boiling point fractins of standard alkanes. Gas chromatographs showed unique peak differences between culture samples of different ages and termperatures. The boiling point fraction of 60-110 degrees Celcius contained unique peaks that were observed with Penicillium and occurred as early as two weeks of age. The fungal cultures showed decreases in the relative percent of the areas of the gas chromatograph in higher boiling point fractions, by the age of 5 weeks. These fungal chemical byproducts found in the 60-100 degrees Celcius fraction correspond to compounds of 6-10 carbon atoms. This research demonstrates that Penicillium can grow in naphthenic metalworking fluid and thus, alter the chemical composition of that fluid.Master'sCollege of Arts and Sciences: BiologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/117691/1/Cossaboom.pd

Genetic variability and the classification of hepatitis E virus

The classification of hepatitis E virus (HEV) variants is currently in transition without agreed definitions for genotypes and subtypes or for deeper taxonomic groupings into species and genera that could incorporate more recently characterized viruses assigned to the Hepeviridae family that infect birds, bats, rodents, and fish. These conflicts arise because of differences in the viruses and genomic regions compared and in the methodology used. We have reexamined published sequences and found that synonymous substitutions were saturated in comparisons between and within virus genotypes. Analysis of complete genome sequences or concatenated ORF1/ORF2 amino acid sequences indicated that HEV variants most closely related to those infecting humans can be consistently divided into six genotypes (types 1 to 4 and two additional genotypes from wild boar). Variants isolated from rabbits, closely related to genotype 3, occupy an intermediate position. No consistent criteria could be defined for the assignment of virus subtypes. Analysis of amino acid sequences from these viruses with the more divergent variants from chickens, bats, and rodents in three conserved subgenomic regions (residues 1 to 452 or 974 to 1534 of ORF1 or residues 105 to 458 of ORF2) provided consistent support for a division into 4 groups, corresponding to HEV variants infecting humans and pigs, those infecting rats and ferrets, those from bats, and those from chickens. This approach may form the basis for a future genetic classification of HEV into four species, with the more divergent HEV-like virus from fish (cutthroat trout virus) representing a second genus