J.M. Dabbs to Professor Silver, 5 June 1959

Professional correspondenc

The Pinhole/Occulter Facility

Scientific objectives and requirements are discussed for solar X-ray observations, coronagraph observations, studies of coronal particle acceleration, and cosmic X-ray observations. Improved sensitivity and resolution can be provided for these studies using the pinhole/occulter facility which consists of a self-deployed boom of 50 m length separating an occulter plane from a detector plane. The X-ray detectors and coronagraphic optics mounted on the detector plane are analogous to the focal plane instrumentation of an ordinary telescope except that they use the occulter only for providing a shadow pattern. The occulter plane is passive and has no electrical interface with the rest of the facility

Cloning, sequencing, and characterization of the hexahydro-1,3,5-trinitro-1,3,5-triazine degradation gene cluster from Rhodococcus rhodochrous

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a high explosive which presents an environmental hazard as a major land and groundwater contaminant. Rhodococcus rhodochrous strain 11Y was isolated from explosive contaminated land and is capable of degrading RDX when provided as the sole source of nitrogen for growth. Products of RDX degradation in resting-cell incubations were analyzed and found to include nitrite, formaldehyde, and formate. No ammonium was excreted into the medium, and no dead-end metabolites were observed. The gene responsible for the degradation of RDX in strain 11Y is a constitutively expressed cytochrome P450-like gene, xpLA, which is found in a gene cluster with an adrenodoxin reductase homologue, xplB. The cytochrome P450 also has a flavodoxin domain at the N terminus. This study is the first to present a gene which has been identified as being responsible for RDX biodegradation. The mechanism of action of XplA on RDX is thought to involve initial denitration followed by spontaneous ring cleavage and mineralization

Assessing the affective Simon paradigm as a measure of individual differences in implicit social cognition about death

The authors describe the use of the affective Simon paradigm as a measure of individual differences in implicit social cognition about death. Participants made verbal responses of "good" or "bad" to death and neutral stimuli based on whether the word was a person or a thing. Participants also completed the Revised Death Attitude Profile, a Stroop task, and a version of the Implicit Association Test using death-related words. Although the affective Simon paradigm has some theoretical advantages over the IAT and Stroop procedures, we found no evidence for its validity in the present study

A time-resolved fluorescence immunoassay for the measurement of testosterone in saliva: Monitoring of testosterone replacement therapy with testosterone buciclate

Monitoring of testosterone replacement therapy requires a reliable method for testosterone measurement. Determination of salivary testosterone, which reflects the hormone's biologically active plasma fraction, is a superior technique for this purpose. The aim of the present study was to establish a new sensitive time-resolved fluorescence immunoassay for the accurate measurement of testosterone levels in saliva and to validate it by monitoring testosterone replacement therapy in eight hypogonadal men. A clinical phase I- study with the new ester testosterone buciclate was performed to search for new testosterone preparations to produce constant serum levels in the therapy of male hypogonadism. After two control examinations eight male patients with primary hypogonadism were randomly assigned to two treatment groups (n = 2x4) and given single doses of either 200 mg (group I) or 600 mg (group II) testosterone buciclate intramuscularly. Saliva and blood samples were obtained 1, 2, 3, 5 and 7 days post injection and then weekly for three months. The time-resolved fluorescence immunoassay for salivary testosterone shows a detection limit of 16 pmol/l, an intra-assay CV of 8.9% (at a testosterone concentration of 302 pmol/l), an inter-assay CV of 8.7% (at a testosterone concentration of 305 pmol/l) and a good correlation with an established radioimmunsassay of r = 0.89. The sample volume required by this method is only 180 mu l for extraction and duplicate determination. The assay procedure requires no more than three hours. In group I (200 mg) testosterone did not increase to normal levels either in saliva or in serum. However, in group II, androgen levels increased significantly and were maintained in the normal range for up to 12 weeks with maximal salivary testosterone levels of 303 +/- 18 pmol/l (mean+/-SE) and maximal testosterone levels of 13.1 +/- 0.9 nmol/l (mean+/-SE) in serum in study week 6 and 7. The time-resolved fluorescence immunoassay for salivary testosterone provides a useful tool for monitoring androgen status in men and women and is well suited for the follow-up of testosterone replacement therapy on an outpatient basis. The long-acting ester testosterone buciclate is a promising agent for substitution therapy of male hypogonadism and in combination with testosterone monitoring in saliva offers an interesting new perspective for male contraception

Development of an atom buncher

An ‘‘atom buncher’’ for controlling the concentration of gaseous samples has been conceptualized, evaluated theoretically, fabricated, and tested with excellent results. In effect, the atom buncher greatly increases the probability that a free atom will be in a small detector volume at a desired time. This was accomplished by using cryogenic techniques to condense atoms on a small spot and a pulsed laser to momentarily heat the spot to release the atoms at the desired time. Our work on noble gas atom counting by using resonance ionization spectroscopy is discussed as one example of the applications of the atom buncher

Pseudo-Foster Kennedy Syndrome due to unilateral optic nerve hypoplasia: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pseudo-Foster Kennedy Syndrome is described as unilateral optic disc swelling with contralateral optic atrophy in the absence of an intracranial mass causing compression of the optic nerve. This occurs typically due to bilateral sequential optic neuritis or ischaemic optic neuropathy.</p> <p>Case Presentation</p> <p>We describe a case of pseudo-Foster Kennedy Syndrome in a two year old boy with unilateral papilloedema due to a congenital optic disc anomaly in one eye preventing transmission of raised intracranial pressure to the optic nerve.</p> <p>Conclusion</p> <p>From our findings we conclude that congenital optic nerve hypoplasia is a cause of pseudo-Foster Kennedy Syndrome.</p

PSYCHOSOCIAL FACTORS AND MOBILE HEALTH INTERVENTION: IMPACT ON LONG-TERM OUTCOMES AFTER LUNG TRANSPLANTATION

Identifying and intervening on modifiable risk factors may improve outcomes in lung transplantation (LTx), which, despite recent improvements, remain suboptimal. Evidence suggests that two modifiable risk factors, psychiatric disorders and nonadherence, may improve LTx outcomes in the short-term; however, neither has been explored in the long-term. Therefore, the overarching goal of this dissertation was to determine the long-term impact of these modifiable risk factors and intervention to attenuate them. First, we examined the relationship of pre- and early post-transplant psychiatric disorders on LTx-related morbidity and mortality for up to 15 years post-LTx. Our sample included 155 1-year LTx survivors enrolled in a prospective study of mental health post- LTx. We found that depression during the first year post-LTx increased risk of BOS, mortality and graft loss by nearly twofold, and that pre-transplant depression and pre- and post-transplant anxiety were not associated with clinical outcomes. Next, we examined the impact of a mobile health intervention designed to promote adherence to the post-LTx regimen, PocketPATH, on long-term LTx-related morbidity, mortality and nonadherence. We conducted two follow-up studies to the original yearlong randomized controlled trial in which participants assigned to PocketPATH showed improved adherence to the regimen, relative to usual care. Among the 182 LTx recipients (LTxRs) who survived the original trial, we found that PocketPATH had a protective indirect effect on mortality by promoting LTxRs’ communication with the LTx team during the first year. Among the 104 LTxRs who completed the follow-up assessment, we found that PocketPATH’s adherence benefits over the first year were not sustained into the long-term, although LTxRs assigned to PocketPATH were more likely than LTxRs assigned to usual care to perform the home self-care tasks of the regimen at follow-up. Median time since LTx for participants in both follow-up studies was 4.2 years (range, 2.8-5.7 years). This dissertation presents an important first step toward identifying and intervening on modifiable risk factors to improve long-term LTx outcomes. Mobile health technologies offer limitless potential to target these risk factors and others. More work is needed to determine specific features and long-term patient engagement strategies that will optimize and sustain intervention effectiveness