Electron-Hole Condensation in Semiconductors: Electrons and holes condense into freely moving liquid metallic droplets, a plasma phase with novel properties.

In Ge and Si, and also in Ge-Si alloys (74), there is extensive evidence for the stable binding of electrons and holes into a cold plasma of constant density, which undergoes a phase separation. Liquid metallic drops 1 to 300 microm in size are formed, with lifetimes ranging from 0.1 to 600 microsec. For Ge a surprising amount is known: the phase diagram, the surface energy, the work function, the decay kinetics. Much less is known for Si. There is good agreement between theoretical and experimental values of the liquid density, the critical density, the critical temperature, and the binding energy. The stability of the liquid phase is strikingly dependent on band structure. The multivalley structure and mass anisotropy of Si, Ge, and Ge-Si, together with their indirect band gap, are no doubt responsible for the observed stability in these crystals. In the similar semiconductor gallium phosphide, drops have not yet been observed, most likely because the high impurity content traps the excitons. In gallium arsenide the existence of drops is controversial (75). Undoubtedly drops will be found to exist in other semiconductors, perhaps at even higher temperatures. This is an exciting field for the experimentalist; new phenomena are being rapidly discovered, usually before they are predicted. For the theorist, the electron-hole drop is of high intrinsic interest. It represents the first example of a quantum liquid of constant density in a periodic crystal lattice. A number of challenging experimental and theoretical problems remain.

Insights into psychosis risk from leukocyte microRNA expression.

Dysregulation of immune system functions has been implicated in schizophrenia, suggesting that immune cells may be involved in the development of the disorder. With the goal of a biomarker assay for psychosis risk, we performed small RNA sequencing on RNA isolated from circulating immune cells. We compared baseline microRNA (miRNA) expression for persons who were unaffected (n=27) or who, over a subsequent 2-year period, were at clinical high risk but did not progress to psychosis (n=37), or were at high risk and did progress to psychosis (n=30). A greedy algorithm process led to selection of five miRNAs that when summed with +1 weights distinguished progressed from nonprogressed subjects with an area under the receiver operating characteristic curve of 0.86. Of the five, miR-941 is human-specific with incompletely understood functions, but the other four are prominent in multiple immune system pathways. Three of those four are downregulated in progressed vs. nonprogressed subjects (with weight -1 in a classifier function that increases with risk); all three have also been independently reported as downregulated in monocytes from schizophrenia patients vs. unaffected subjects. Importantly, these findings passed stringent randomization tests that minimized the risk of conclusions arising by chance. Regarding miRNA-miRNA correlations over the three groups, progressed subjects were found to have much weaker miRNA orchestration than nonprogressed or unaffected subjects. If independently verified, the leukocytic miRNA biomarker assay might improve accuracy of psychosis high-risk assessments and eventually help rationalize preventative intervention decisions.

Simultaneous infection with Treponema pallidum and herpes simplex virus.

Two cases are presented of simultaneous infection with Treponema pallidum and herpes simplex virus. The occasional concurrence of these diseases suggests that all cases of herpes genitalis, including those with negative darkfield examinations and initial nonreactive serologic tests for syphilis, should be followed in two to four weeks by a repeat serologic test for syphilis.

Opportunistic fungi in Detroit's rats and opossum.

Four Norway rats (Rattus norvegicus) and one opossum (Didelphis virginiana) were surveyed for the presence of fungi. Eighteen different fungi were isolated from rat samples and six from the opossum, including Trichophyton mentagrophytes. Hair and skin scrapings from laboratory raised Norway rats, bedding and air from the room yielded only Penicillium sp.

Bacteriophage typing of Proteus mirabilis, Proteus vulgaris, and Proteus morganii.

A bacteriphage typing scheme for differentiating Proteus isolated from clinical specimens was developed. Twenty-one distinct patterns of lysis were seen when 15 bacteriophages isolated on 8 Proteus mirabilis, 1 P. vulgaris, and 1 P. morganii were used to type 162 of 189 (85.7%) P. mirabilis and P. vulgaris isolates. Seven phages isolated on 3 P. morganii were used to type 13 of 19 (68.4%) P. morganii isolates. Overall, 84.1% of the 208 isolates were lysed by at least 1 phage at routine test dilution (RTD) or 1,000 x RTD. Fifty isolates, retyped several weeks after the initial testing, showed no changes in lytic patterns. The phages retained their titers after storage at 4 C for several months. A computer analysis of the data showed that there was no relationship between the source of the isolate and bacteriophage type. This bacteriophage typing system may provide epidemiological information on strains involved in human infections.

An indirect fluorescent antibody technique for Haemophilus ducreyi.

An indirect fluorescent antibody technique which allows the detection of antibody against or the recognition of Haemophilus ducreyi has been developed. Heat inactivated antiserum was reacted uith prepared smears of Haimophilus species and selected organisms commonly associated with penile ulcerations. In serum absorbed with Haemophilus sp no fluorescence was observed with 156 heterologous organisms, but all six strains of bacteriologically confirmed H. ducreyi gave significant reactions with the absorbed anti-WD-68 serum.

Analytical isoelectric focusing of secreted dermatophyte proteins applied to taxonomic differentiation of Microsporum and Trichophyton species (preliminary studies).

Culture filtrates were prepared from dermatophytes under standard conditions and adapted for analytical isoelectric focusing in thin layer polyacrylamide gels over the pH range 3.5-9.5. Dermatophytes grown in trypticase soy broth secreted a large number of proteins displaying a wide range of isoelectric points (pIs). Trichophyton megninii extracts contained a triplet of proteins focusing in the pH 8.0-8.5 range that were absent in taxonomically related T. kuryangei isolates. Single ascospore isolates and standard tester strains of Nannizzia otae (+) mating type were differentiated from the (-) mating type by proteins focusing at pH 6.5 and 8.4. These were markedly reduced in the (+) type. The isofocused pattern of Microsporum canis conformed closely to the (-) mating type of N. otae. The protein patterns of T. megninii and T. kuryangei were distinct from those obtained with M. canis and M. equinum because of an intense-staining broad protein band, pI 7.2, and three periodic acid-Schiff-positive glycoproteins focusing in the acidic range which were absent in the Microsporum species. A characteristic protein or doublet (pI 8.7) was present in the Microsporum species and absent in the Trichophyton species. Analytical isoelectric focusing is a potentially useful method to distinguish inter- and intra-species differences in the pattern of secreted dermatophyte proteins present in culture filtrates and in trichophytins. The information derived may be useful in the classification of species.

Curvularia lunata in experimental phaeohyphomycosis.

Curvularia lunata strain SP, isolated from a disseminated human infection, infected normal mice, but three other strains of C. lunata and one each of C. pallescens and C. spicifera did not. The SP strain was recovered in cultures from, and hyphal filaments were observed in, abscesses in the liver and spleen of experimentally infected mice. All strains of Curvularia infected mice treated with 400 rads X-irradiation and 10.0 mg cortisone, but at 400 rads and 5.0 mg only two strains of C. lunata (SP and Ghosh) and C. pallescens and C. spicifera infected mice. At 200 rads and 10.0 mg, C. lunata Sp, C. pallescens and C. spicifera; and at 200 rads and 5.0 mg, only C. lunata SP and C. pallescens caused infection. After X-irradiation (200 or 400 rads) or cortisone (5.0 or 10.0 mg) alone only C. lunata SP caused infections in mice.

Mating behaviour of Keratinomyces ceretanicus with Arthroderma uncinatum.

Keratinomyces ceretanicus was described as a new taxon distinct from Trichophyton ajelloi. Because of the morphological similarity between the two species, their mating behaviour was studied. The optimum temperature for growth of K. ceretanicus was found to be 25 degrees C rather than 17 degrees C. The type culture produced moderate numbers of microconidia on potato glucose agar after 2 weeks at 25 degrees C and a large number of smooth, thick-walled, cylindro-fusiform, 7-to 12-celled macroconidia. On Sabouraud glucose agar containing chloramphenicol and cycloheximide growth was partially but not completely inhibited. When crossed on a soil-hair medium, K. ceretanicus produced fertile gymnothecia typical of Arthroderma uncinatum with 10 (-) mating type isolates of A. uncinatum. As a result, it is concluded that K. ceretanicus is a facultative synonym of T. ajelloi.

Influence of genital herpes on results of fluorescent treponemal antibody absorption test.

Both the fluorescent treponemal antibody absorption (FTS-ABS) test and Venereal Disease Laboratory (VDRL) test for syphilis were performed routinely on 113 men with histories of genital ulcerations. The difference in negative VDRL and borderline FTS-ABS results between patients with and without herpes simplex virus in their genital ulcers and no evidence of previous or untreated syphilis was not statistically significant. Furthermore, use of the FTA-ABS test as a confirmatory rather than a screening test eliminates false-positive, borderline, or reactive results in patients with non-syphilitic ulcers.

Class-specific antibody in human dermatophytosis reactive with Trichophyton rubrum derived antigen.

Dermatophyte infections induce a humoral immune response and an enzyme linked immunosorbent assay was used to detect specific antibody classes against antigen derived from Trichophyton rubrum. Sera from 19 acute patients, 18 chronic patients, and 27 normal controls were evaluated. Mean IgG titers against dermatophyte antigen were significantly higher in all patients than in controls. Mean IgM levels were significantly higher in acute patients than in controls. No significant difference was detected in IgE titers between the patients and controls. These results do not reveal whether the humoral immune response has a role in the progression of the infection.

Acquired ability of Staphylococcus aureus to produce toxic shock-associated protein and resulting illness in a rabbit model.

Staphylococcus aureus from patients with toxic shock syndrome (TSS) produce TSS toxin 1. We transferred, by a bacteriophage, the ability to produce TSS toxin 1 from a TSS toxin 1-positive to a TSS toxin 1-negative strain of S. aureus. This recombinant strain produced TSS toxin 1 as confirmed by isoelectric focusing, immunodiffusion, radioimmunoassay, and autoradiography. The recombinant produced TSS-like illness in rabbits, and was significantly (P less than 0.001) more lethal than the recipient strain. Both strains produced fever and diarrhea, but, in addition, rabbits challenged with the recombinant also developed lowered blood pressure (P = 0.002), conjunctival hyperemia, erythroderma, and respiratory distress. Histopathological findings in rabbits challenged with the recombinant strain were remarkably similar to those described for humans with TSS, e.g., erythrophagocytosis, liver "triaditis," and vasodilatation. This study demonstrates that this protein may contribute to the pathogenesis of the TSS.