Tunable electrochemistry of gold-silver alloy nanoshells

Nano Research - The widespread and increasing interest in enhancing biosensing technologies by increasing their sensitivities and lowering their costs has led to the exploration and application of...     

The "first generation" of endovascular stent-grafts for patients with aneurysms of the descending thoracic aorta

OBJECTIVE: Our goal was to determine whether endovascular stent-grafting is feasible and effective for patients with aneurysms of the descending thoracic aorta. METHODS: Starting in July 1992, we conducted a prospective, uncontrolled clinical trial in 103 patients (mean age 69 years [range 34-89 years]) who underwent endovascular treatment of aneurysms of the descending thoracic aorta using a custom-fabricated, self-expanding stent-graft device. Follow-up was 100% complete and averaged 22 months. Sixty-two patients (60%) were judged not to be reasonable candidates for a conventional "open" surgical procedure. RESULTS: Complete thrombosis of the aneurysm was ultimately achieved in 86 (83%) patients. The early mortality rate was 9% +/- 3% (+/- 70% CL). Multivariable analysis revealed that myocardial infarction or stroke was linked with a higher likelihood of early death (P = .001). Early serious complications included paraplegia in 3% +/- 2% and stroke in 7% +/- 3%. Actuarial survival estimates at 1 year and 2 years were 81% +/- 4% and 73% +/- 5% (+/- 1 SE), respectively; being judged not to be a surgical candidate portended a higher probability of death (P = .003). According to the intent-to-treat principle, "treatment failure" (including all late sudden unexplained deaths) occurred in 38 patients; 53% +/- 10% of patients were free from treatment failure at 3.7 years. Stent-graft related complications occurred commonly and were linked with several anatomic, technical, and patient-related risk factors. CONCLUSIONS: This 5-year clinical trial involving use of a "first generation" device indicates that endovascular stent-grafting of descending thoracic aortic aneurysms is feasible with acceptable medium-term results. More refined, commercially developed devices available today offer less traumatic and more precise stent-graft deployment; these major technical advantages, coupled with important lessons we have learned over time and better patient selection, should be associated with more salutary clinical results in the future.     

The impact of employment and serious illness on grandmothers who are raising their grandchildren

Increasing numbers of children are living in families consisting of grandparents and grandchildren. This paper presents findings of a study in which 123 caregiving grandmothers were interviewed. Fifty-eight percent of these grandmothers were "career caregivers," whose homes were always filled with a child or grandchild. Most of them were in good to excellent physical health and their mental health was at least as good as that of a national sample. Regression analyses found that having a life-threatening physical condition, being younger and white explained psychological anxiety; and having a life-threatening physical condition and not being employed explained psychophysiological mental health symptoms. These findings suggest that some grandmothers are at risk for mental health symptoms and raise questions about the implications of caregiving of grandchildren for women.     

Lobectomy combined with volume reduction for patients with lung cancer and advanced emphysema

Methanol-induced conformational transitions of hen egg white lysozyme were investigated with a combined use of far- and near-UV CD and NMR spectroscopies, ANS binding and small-angle X-ray scattering. Addition of methanol induced no global change in the native conformation itself, but induced a transition from the native state to the denatured state which was highly cooperative, as shown by the coincidence of transition curves monitored by the far- and near-UV CD spectroscopy, by isodichroic points in the far- and near-UV CD spectra and by the concomitant disappearance of individual 1H NMR signals of the native state. The ANS binding experiments could detect no intermediate conformer similar to the molten globule state in the process of the methanol denaturation. However, at high concentration of methanol, e.g., 60% (v/v) methanol/water, a highly helical state (H) was realized. The H state had a helical content much higher than the native state, monitored by far-UV CD spectroscopy, and had no specific tertiary structure, monitored both by near-UV CD and NMR spectroscopy. The radius of gyration in the H state, 24.9 angstroms, was significantly larger than that in the native state (15.7 angstroms). The Kratky plot for the H state did not show a clear peak and was quite similar to that for the urea-denatured state, indicating a complete lack of globularity. Thus we conclude that the H state has a considerably expanded, flexible broken rod-like conformation which is clearly distinguishable from the "molten globule" state. The stability of both N and H states depends on pH and methanol concentration. Thus a phase diagram involving N and H was constructed.     

Genetic effects of 1,3-butadiene and associated risk for heritable damage

A summary of the results of the studies conducted in the EU Project "Multi-endpoint analysis of genetic damage induced by 1,3-butadiene and its major metabolites in somatic and germ cells of mice, rats and man" is presented. Results of the project are summarized on the detection of DNA and hemoglobin adducts, on the cytotoxic and clastogenic effects in somatic and germinal cells of mice and rats, on the induction of somatic mutations at the hprt locus of experimental rodents and occupationally exposed workers, on the induction of dominant lethal mutations in mice and rats, and on heritable translocations induced in mice, after exposure to butadiene (BD) or its major metabolites, butadiene monoepoxide (BMO), diepoxybutane (DEB) and butadiene diolepoxide (BDE). The primary goal of this project was to collect experimental data on the genetic effects of BD in order to estimate the germ cell genetic risk to humans of exposure to BD. To achieve this, the butadiene exposure are based on data for heritable translocations and bone marrow micronuclei induced in mice and chromosome aberrations observed in lymphocytes of exposed workers. A doubling dose for heritable translocations in human germ cells of 4900 ppm/h is estimated, which, assuming cumulative BD exposure over the sensitive period of spermatogenesis, corresponds to 5-6 weeks of continuous exposure at the workplace to 20-25 ppm. Alternatively, the rate of heritable translocation induction per ppm/h of BD exposure is estimated to be approximately 0.8 per million live born, compared to a spontaneous incidence of balanced translocations in humans of approximately 800 per million live born. These estimates have large confidence intervals and are only intended to indicate orders of magnitude of human genetic risk. These risk estimates are based on data from germ cells of BD-exposed male mice. The demonstration that clastogenic damage was induced by DEB in preovulatory oocytes at doses which were not ovotoxic implies that additional studies on the response of mammalian female germ cells to BD and its metabolites are needed. The basic assumption of the above genetic risk estimates is that experimental mouse data obtained after BD exposure can be extrapolated to humans. Several points exist in the present report and in the literature which contradict this assumption: (1) the level of BMO-hemoglobin adducts was significantly elevated in BD-exposed workers; however, it was considerably lower than would have been predicted from comparable rat and mouse exposures; (2) the concentrations of the metabolites DEB and BMO were significantly higher in mouse than in rat blood after BD exposure. Thus, while metabolism of BD is qualitatively similar in the two species, it is quantitatively different; (3) no increase of HPRT mutations was shown in 19 workers exposed on average to 1.8 ppm of BD, while in a different population of workers from a US plant exposed on average to 3.5 ppm of BD, a significant increase of HPRT variants was detected; and (4) data from cancer bioassays and cancer epidemiology suggest that rat is a more appropriate model than mouse for human cancer risk from BD exposure. However, the dominant lethal study in rats gave a negative result. At present, we do not know which BD metabolite(s) may be responsible for the genetic effects even though the bifunctional alkylating agent DEB is the most likely candidate for the induction of clastogenic events. Unfortunately, methods to measure DEB adducts in hemoglobin or DNA are only presently being developed. Despite these several uncertainties the use of the mouse genetic data is regarded as a justifiable and conservative approach to human genetic risk estimation given the considerable heterogeneity observed in the biotransformation of BD in humans.     

Treatment of pulmonary hypertension with inhaled nitric oxide during hepatic transplantation in an adolescent: reversibility of pulmonary hypertension after transplantation

Accusations of rape or sexual harassment are currently very high-profile in the military. This article discusses rape allegations in the military legal system from a psychiatric perspective. The original definition of "rape trauma syndrome" and subsequent psychiatric thinking about the diagnosis are briefly outlined. Common reactions seen in military victims in this era are described. A prototypical military case is presented. An adequate evaluation of an alleged victim is outlined. Credentials and preparation of an expert witness are also briefly discussed, with cautions about the use of expert testimony in cases of alleged sexual assault and rape trauma syndrome.     

Speech perception performance in experienced cochlear-implant patients receiving the SPEAK processing strategy in the Nucleus Spectra-22 cochlear implant

Sixteen experienced cochlear implant patients with a wide range of speech-perception abilities received the SPEAK processing strategy in the Nucleus Spectra-22 cochlear implant. Speech perception was assessed in quiet and in noise with SPEAK and with the patients' previous strategies (for most, Multipeak) at the study onset, as well as after using SPEAK for 6 months. Comparisons were made within and across the two test sessions to elucidate possible learning effects. Patients were also asked to rate the strategies on seven speech recognition and sound quality scales. After 6 months' experience with SPEAK, patients showed significantly improved mean performance on a range of speech recognition measures in quiet and noise. When mean subjective ratings were compared over time there were no significant differences noted between strategies. However, many individuals rated the SPEAK strategy better for two or more of the seven subjective measures. Ratings for "appreciation of music" and "quality of my own voice" in particular were generally higher for SPEAK. Improvements were realized by patients with a wide range of speech perception abilities, including those with little or no open-set speech recognition.     

Migration and right atrial perforation of an Accufix atrial lead retention wire following partial lead removal during myomectomy

A 36-year-old man with a history of hypertrophic obstructive cardiomyopathy presented to the emergency room with "stabbing" chest pain. He had undergone dual-chamber pacemaker implantation in 1993 using an atrial lead (Accufix; Telectronics; Englewood, Colo) and a myomectomy in 1996 during which the distal portion of the atrial lead was removed. Digital fluoroscopy revealed that the retention wire had migrated out of the remaining atrial lead and perforated the right atrium. The retention wire was successfully removed percutaneously. The need for complete removal of the retention wire in the Accufix lead at the time of open-heart surgery is emphasized.     

Numerical simulation of steady planar die swell for a Newtonian fluid using the spectral element method

This paper is concerned with two dimensional numerical simulations of plane extrusion of a Newtonian fluid. The problem is discretized using the spectral element method and the free surface is evolved according to an ALE treatment. Numerical simulations are performed over a wide range of Reynolds and Weber numbers to highlight the effects of inertia and surface tension, respectively. Convergence of the numerical approximations with respect to polynomial order is demonstrated for the sensitive measures of free surface location and downstream relaxation distance. The higher the inertia the further downstream the relaxation occurs. Numerical results show good qualitative and quantitative agreement with predictions of other numerical schemes and experiments.