Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 1. Urogenital morphology and placental androgen production during fetal life

The pre-T cell receptor (TCR) associates with CD3-transducing subunits and triggers the selective expansion and maturation of T cell precursors expressing a TCR-beta chain. Recent experiments in pre-Talpha chain-deficient mice have suggested that the pre-TCR may not be required for signaling allelic exclusion at the TCR-beta locus. Using CD3-epsilon- and CD3-zeta/eta-deficient mice harboring a productively rearranged TCR-beta transgene, we showed that the CD3-gammadeltaepsilon and CD3-zeta/eta modules, and by inference the pre-TCR/CD3 complex, are each essential for the establishment of allelic exclusion at the endogenous TCR-beta locus. Furthermore, using mutant mice lacking both the CD3-epsilon and CD3-zeta/eta genes, we established that the CD3 gene products are dispensable for the onset of V to (D)J recombination (V, variable; D, diversity; J, joining) at the TCR-beta, TCR-gamma, and TCR-delta loci. Thus, the CD3 components are differentially involved in the sequential events that make the TCR-beta locus first accessible to, and later insulated from, the action of the V(D)J recombinase.     

Human immunodeficiency virus seropositivity in adolescents with syphilis

OBJECTIVE: The purpose of this study was to assess the relationship between syphilis and human immunodeficiency virus (HIV) infection among inner-city, minority group adolescents. METHODS: From August 1989 through June 1990, serum from all positive serologic tests for syphilis, obtained from patients attending a comprehensive adolescent health center in an acquired immunodeficiency syndrome epicenter and its two school-based clinics, were frozen without patient identifiers and were subsequently screened for HIV by enzyme-linked immunosorbent assay with confirmatory Western blot for positives. In addition, a retrospective chart review was performed for all patients with a positive serologic test for syphilis during the study period. RESULTS: Of the 59 specimens with a positive syphilis serologic test, 9 (15.3%) were HIV seropositive. Of the patients with syphilis, 57.4% were black and 42.6% were Hispanic; 16.4% were male (mean age 18.1) and 83.6% were female (mean age 17.8). Only 1 subject (female) was an injection drug user; 4 of the male subjects self-identified as having had sex with other males. Of the subjects, 27.8% had primary, 19.7% had secondary, and 52.5% had latent syphilis at the time of diagnosis. A prior or concurrent sexually transmitted disease was present in 90% of the males and 80% of the females; gonorrhea was the most prevalent sexually transmitted disease in the males (89%) and chlamydia was most prevalent in the females (35%). A history of chancroid and/or herpes was present in 16.4% of the subjects. CONCLUSIONS: It is concluded that the diagnosis of syphilis in an adolescent is a risk factor for HIV infection. All sexually active adolescents should be routinely screened for syphilis, regardless of sexual practices. Those with syphilis should be specifically counseled about their increased risk for HIV infection and the importance of consistent condom use, and they should be referred for formal HIV pretest counseling.     

Distributed Store-and-Forward Deadlock Detection and Resolution Algorithms

Distributed algorithms for the detection and resolution of deadlocks in store-and-forward computer communication networks are presented and validated. The algorithms use a fixed amount of storage at each node (that is independent of the size of the network). The detection algorithm is simple but requires network-wide coordination. The resolution algorithm is based on earlier approaches, but uses the network-wide coordination to address certain synchronization problems. When the detection and resolution algorithms are merged, it is guaranteed that packets will arrive at their destinations in finite time.     

Multilocular thymic cysts: imaging features in children with human immunodeficiency virus infection

Southern blot analysis has been the best method available for the screening and detection of mitochondrial DNA (mtDNA) rearrangements. Recent developments in polymerase chain reaction (PCR) technology allowed the amplification of the whole mitochondrial genome (16.6 kb), making PCR a potentially useful technique for the detection of mtDNA deletions. We tested the usefulness of whole mitochondrial genome PCR by studying skeletal muscle DNA from seven patients with single and multiple deletions and controls from ages 3 to 91 years old. Specific patterns for single and multiple deletions were obtained with whole genome PCR, which were confirmed by the Southern analysis with probes hybridizing to mtDNA sequences. Amplifications from young controls (3 to 23 years old) yielded only one band (16.5 kh) while amplification from older controls revealed one or more additional smaller bands. The amplification from the 91-year-old control showed a pattern similar to amplifications from patients with multiple mtDNA deletions. Although single and multiple mtDNA deletions could be readily detected from patient samples, the high sensitivity of this method can lead to false positive results due to the presence of age-related deletions in old control samples. Despite its limitations, whole mitochondrial genome PCR can be useful for the detection of single deletions in muscle samples obtained from young individuals since the levels of age-related deletions are too low to be amplified.     

Theoretical studies of optical modulation in lattice matched and strained quantum wells due to transverse electric fields

Electrooptical modulators based on quantum well structures have become an important area of research due to potential applications in high-speed optical modulation and image processing. In this paper, we examine the physics of a quantum well modulator within the generalized Kohn-Luttinger Hamiltonian. Issues of importance for the modulator structure are the excitonic absorption shift, exciton binding energy, line broadening, tunneling rates for electrons and holes in the presence of a transverse electric field, and changes in optical absorption coefficients as a function of electric field. A formalism to study these effects for both lattice matched and nonlattice matched quantum well structures is provided and the potential of material tailoring for specific optical response is discussed. It is shown that the reliability of this technology is critically related to the fabrication of high-quality interfaces and alloys since even a one-monolayer variation in quantum well size can have a substantial effect on the modulation properties.     

Effect of self-differentiation and anonymity in group on deindividuation.

Investigated the effects of deindividuating conditions (i.e., anonymity) on the behaviors and feelings of self-differentiated and less self-differentiated individuals. 40 male 17–18 yr olds were divided on the basis of their scores on the portable rod-and-frame test into self-differentiated and undifferentiated groups. Each S was exposed to transgressive and prosocial behavior of 2 group members who were confederates. Exposure to the models' behavior occurred under conditions of anonymity or identifiability. Additionally, measures of Ss' feelings were taken. Data indicate that relative to identifiability conditions, the transgressions and prosocial actions of the models had stronger effects on the behaviors of undifferentiated Ss under anonymity conditions. Also, undifferentiated Ss felt less self-conscious and less inhibited under anonymity than identifiability conditions. The behaviors and feelings of self-differentiated Ss were relatively unaffected by the anonymity–identifiability manipulation. A conceptual link between self-differentiation, self-awareness, and deindividuation is proposed. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)