Photoemission Studies of the Initial Adsorption and Growth of Ag on Ge(111)

We present electron diffraction, and high-resolution angle-resolved and angle-integrated photoemission studies of the initial phases of adsorption and growth of Ag on Ge(111). The results provide information on the structural properties of the Ge(111)-c(2×8) substrate surface, show Ag grows upon it almost laminarly at room temperature, and unambiguously demonstrate the presence of a small amount of Ge segregating on top of the growing Ag overlayer. The origins and behavior of these segregated atoms are discussed. Ag films more than a few monolayers thick exhibit quantum well states which are observed to evolve as a function of film thickness.

Structural Analysis and Electronic Properties of in on Si(100) from Synchrotron Photoemission Studies

High-resolution photoemission spectroscopy was used to study the initial growth and interaction of In on Si(100). A quantification of the number of Si surface atoms selectively modified in the presence of an In adatom is enabled by decomposing the Si 2p core level into bulk and surface-shifted components; this analysis leads to an In-Si bonding coordination number determination. The In-to-Si bonding coordination number is 3 for very low In coverages and decreases to 2 for one half monolayer coverage. An analysis of the In 4d core levels indicates that the In adatoms occupy equivalent sites for the first 0.5 monolayers. Surface state emission near the top of the valence band persists for coverages exhibiting no Si 2p surface core level shift; implications regarding the different mechanisms I ehind the surface state and surface core level shift are addressed. The results are consistent with a structural model deduced from electron diffraction, Auger, and scanning electron microscopy studies.

Graphene growth on Ni(111) by transformation of a surface carbide

A novel growth mechanism of graphene on Ni(111) has been discovered that occurs at temperatures below 460 °C. At these conditions, a surface-confined nickel-carbide phase coexists with single layer graphene. The graphene grows by in-plane transformation of the carbide along a one-dimensional phase-boundary, which is distinctively different from known growth processes on other transition metals and on Ni above 460 °C, where carbon atoms attach to "free" edges of graphene islands.

Safety of 1000 CT-guided steroid injections with air used to localize the epidural space

Historically, ESIs were performed without any imaging guidance, resulting in erroneous placement in up to 30% of injections. Fluoroscopic imaging is now used to guide most procedures. Recently, several reports have described the use of CT to guide ESIs instead of fluoroscopy. CT provides the ability to use air as contrast to localize the epidural space. This retrospective review will discuss findings in 1000 CT-guided ESIs with air localization.

Phonon-induced gaps in graphene and graphite observed by angle-resolved photoemission

Mapping by angle-resolved photoemission spectroscopy of the spectral functions of graphite and graphene layers at low temperatures reveals a heretofore unreported gap of ~ 67 meV at normal emission. This gap persists to room temperature and beyond, and diminishes for increasing emission angles. We show that this gap arises from electronic coupling to out-of-plane vibrational modes at the K(¯) point in the surface Brillouin zone in accordance with conservation laws and selection rules governed by quantum mechanics. Our study suggests a new approach for characterizing phonons and electron-phonon coupling in solids.

Using electronic coherence to probe a deeply embedded quantum well in bimetallic Pb/Ag films on Si(111)

We report an experiment in which we utilize electronic coherence to probe a deeply embedded thin film as a quantum well. An atomically uniform Ag film prepared on Si(111) was covered by Pb films up to 70 A thick, and the resulting electronic structure was examined by angle-resolved photoemission spectroscopy. Despite a photoemission escape depth of just a few Angströms and an incommensurate Pb/Ag interface, the data reveal a striking Fabry-Pérot-like structure characteristic of an Ag etalon buried deeply under the Pb overlayers. Our simulations clearly illustrate the manifest coherence of the electronic structures, permitting the characterization of the embedded Ag quantum well.

Phase relations associated with one-dimensional shell effects in thin metal films

The physical and chemical properties of thin metal films show damped oscillations as a function of film thickness (one-dimensional shell effects). While the oscillation period, determined by subband crossings of the Fermi level, is the same for all properties, the phases can be different. Specifically, oscillations in the work function and surface energy are offset by 1/4 of a period. For Pb(111) films, this offset is approximately 0.18 monolayers, a seemingly very small effect. However, aliasing caused by the discrete atomic layer structure leads to striking out-of-phase beating patterns displayed by these two quantities.

Cyclic supraventricular tachycardia in the parturient: to treat or not to treat?

Cardiac arrhythmias are more common in pregnant women than in non-pregnant women. In the asymptomatic pregnant patient with a stable fetus, watchful waiting might be the best strategy. Herein, we describe the first reported case of a pregnant patient who developed cyclic supraventricular tachycardia during labor. No treatment was prescribed, with a good maternal and fetal outcome.

Cost of injuries from a prospective cohort study of North Carolina high school athletes

OBJECTIVE

To estimate the economic cost of injuries in a population of US high school varsity athletes.

DESIGN AND SETTING

The North Carolina High School Athletic Injury Study, conducted from 1996 to 1999, was a prospective cohort study of injury incidence and severity. A two-stage cluster sampling technique was used to select athletic teams from 100 high schools in North Carolina. An injury cost model was used to estimate the economic cost of injury.

PARTICIPANTS

Varsity athletes from 12 sports: football, girls' and boy's soccer, girls' and boys' track, girls' and boy's basketball, baseball, softball, wrestling, volleyball, and cheerleading.

MAIN OUTCOME MEASURES

Descriptive data were collected at the time of injury. Three types of costs were estimated: medical, human capital (medical costs plus loss of future earnings), and comprehensive (human capital costs plus lost quality of life).

RESULTS

The annual statewide estimates were $9.9 million in medical costs, $44.7 million in human capital costs, and $144.6 million in comprehensive costs. The mean medical cost was $709 per injury (95% CI $542 to $927), $2223 per injury (95% CI $1709 to $2893) in human capital costs, and $10,432 per injury (95% CI $8062 to $13,449) in comprehensive costs. Sport and competition division were significant predictors of injury costs.

CONCLUSIONS

Injuries among high school athletes represent a significant economic cost to society. Further research should estimate costs in additional populations to begin to develop cost-effective sports injury prevention programs.

A phase I/II study of galiximab (an anti-CD80 monoclonal antibody) in combination with rituximab for relapsed or refractory, follicular lymphoma

BACKGROUND

Galiximab is a monoclonal antibody that targets CD80, a costimulatory molecule constitutively expressed on follicular and other lymphomas. Modest single-agent clinical activity and tolerability were demonstrated in a phase I study in relapsed or refractory, follicular non-Hodgkin's lymphoma (NHL). A phase I/II study was conducted to evaluate galiximab in combination with a standard course of rituximab. Safety, pharmacokinetics, and efficacy were evaluated.

PATIENTS AND METHODS

Patients with follicular NHL who had relapsed or failed primary therapy were enrolled. Rituximab-refractory patients (no response or a response with time to progression <6 months) were excluded. Patients received 4 weekly i.v. infusions of galiximab (125, 250, 375, or 500 mg/m(2)) and rituximab (375 mg/m(2)). International Workshop Response Criteria (IWRC) were used to evaluate response.

RESULTS

Seventy-three patients received treatment. All had received at least one prior lymphoma therapy; 40% were rituximab naive. Infusions were delivered in an outpatient setting and were well tolerated. The most common study-related adverse events (AE) were lymphopenia, leukopenia, neutropenia, fatigue, and chills. The overall response rate at the recommended phase II dose of galiximab (500 mg/m(2)) was 66%: 19% complete response, 14% unconfirmed complete response, and 33% partial response. The median progression free survival was 12.1 months. Combination therapy did not appear to alter pharmacokinetics.

CONCLUSION

These results indicate that galiximab can be safely combined with a standard course of rituximab. This doublet biologic approach offers the potential to avoid or delay chemotherapy or to integrate with other lymphoma therapies. A phase III, randomized study evaluating clinical benefit of rituximab versus the combination has been initiated.

Incidence and lifetime costs of injuries in the United States

BACKGROUND

Standardized methodologies for assessing economic burden of injury at the national or international level do not exist.

OBJECTIVE

To measure national incidence, medical costs, and productivity losses of medically treated injuries using the most recent data available in the United States, as a case study for similarly developed countries undertaking economic burden analyses.

METHOD

The authors combined several data sets to estimate the incidence of fatal and non-fatal injuries in 2000. They computed unit medical and productivity costs and multiplied these costs by corresponding incidence estimates to yield total lifetime costs of injuries occurring in 2000.

MAIN OUTCOME MEASURES

Incidence, medical costs, productivity losses, and total costs for injuries stratified by age group, sex, and mechanism.

RESULTS

More than 50 million Americans experienced a medically treated injury in 2000, resulting in lifetime costs of 406 billion dollars; 80 billion dollars for medical treatment and 326 billion dollars for lost productivity. Males had a 20% higher rate of injury than females. Injuries resulting from falls or being struck by/against an object accounted for more than 44% of injuries. The rate of medically treated injuries declined by 15% from 1985 to 2000 in the US. For those aged 0-44, the incidence rate of injuries declined by more than 20%; while persons aged 75 and older experienced a 20% increase.

CONCLUSIONS

These national burden estimates provide unequivocal evidence of the large health and financial burden of injuries. This study can serve as a template for other countries or be used in intercountry comparisons.

Coherent Electronic Fringe Structure in Incommensurate Silver-Silicon Quantum Wells

Atomically uniform silver films grown on highly doped n-type Si(111) substrates show fine-structured electronic fringes near the silicon valence band edge as observed by angle-resolved photoemission. No such fringes are observed for silver films grown on lightly doped n-type substrates or p-type substrates, although all cases exhibited the usual quantum-well states corresponding to electron confinement in the film. The fringes correspond to electronic states extending over the silver film as a quantum well and reaching into the silicon substrate as a quantum slope, with the two parts coherently coupled through an incommensurate interface structure.

[Predictive validity of the Scale of Prodromal Symptoms (SOPS)]

INTRODUCTION

We conduct an exploratory factor analysis with the Scale of Prodromal Symptoms (SOPS) items, to determine its psychometric characteristics and construct validity, as well as we analyze criterion or predictive validity of its clinical subscales in the conversion of high mental risk subjects from prodrome to psychosis in a 1 year follow-up period.

METHOD

The subjects were 30 patients referred for evaluation with the Structured Interview of Prodromal Syndromes (SIPS), which includes the SOPS, because of a suspected psychosis prodromal syndrome, a factor analysis with varimax rotation was carried out: Cronbach internal coherence indices were obtained, and predictive validity of the subscales comprising this instrument were analyzed using logistic regression.

RESULTS

Three first-order factors were found, one of them was a homogeneous component made up of negative symptoms, consistent with previous studies, and higher scores were observed in negative, disorganized and general symptoms in males. Cronbach's alpha indices were 0.880, in the recruitment phase of risk patients, and 0.952 one year later. With an incidence rate of psychosis of 26.67 % in the sample studied, during the 1 year follow-up period, an excellent positive predictive value of the SOPS subscales was found, with negative symptoms having the best specificity (95.5 %) and sensitivity (100 %) indices.

CONCLUSIONS

Diagnostic criteria based on the SIPS/ SOPS make it possible to identify persons at high risk of psychosis, and to make an accurate prediction of medium term psychotic episodes. It is a valid, economical and easy to use instrument in primary health care systems.

Umklapp-mediated quantization of electronic states in Ag films on Ge(111)

We employ angle-resolved photoemission to study the electronic structure of atomically uniform films of Ag grown on Ge(111). A new kind of quantum well state is observed near a specific emission direction away from the surface normal. In contrast with the usual quantum well state arising from electron confinement by specular reflections at the surface and interface of the film, the new kind involves retroreflections, or umklapp reflections, at the interface. It requires four reflections, instead of the usual two reflections, to complete a coherent interference path.

Iris ring melanoma: fine needle biopsy

AIMS

To delineate the diagnostic accuracy of fine needle biopsy in iris ring melanoma and determine the tumour related mortality of this neoplasm.

METHODS

A retrospective analysis of 22 patients with iris melanomas that involve the entire 360 degrees of the anterior chamber angle.

RESULTS

Iris ring melanomas were correctly diagnosed in all cases. In 11 of 16 cases (69%) a fine needle biopsy performed 180 degrees away from the main mass was positive for an iris ring melanoma. The tumour related mortality in iris ring melanoma cases was four of 22 patients (18%). Actuarial survival analysis showed a 10 year mortality (Kaplan-Meier) of 15%.

CONCLUSION

A fine needle aspiration biopsy can be used to diagnose an iris ring melanoma. Iris ring melanomas have significant mortality compared with focal tumours.

Peripheral neuropathies in Waldenström's macroglobulinaemia

OBJECTIVE

We sought to determine the prevalence, clinical features, and laboratory characteristics of polyneuropathies in Waldenström's macroglobulinaemia (WM), a malignant bone marrow disorder with lymphocytes that produce monoclonal IgM.

METHODS

We prospectively studied 119 patients with WM and 58 controls. Medical history was taken, and neurological examinations, electrodiagnostic tests, and serum studies were performed by different examiners who were blinded to results except the diagnosis of WM.

RESULTS

Polyneuropathy symptoms, including discomfort and sensory loss in the legs, occurred more frequently (p<0.001) in patients with WM (47%) than in controls (9%). Patients with WM had 35% lower quantitative vibration scores, and more frequent pin loss (3.4 times) and gait disorders (5.5 times) than controls (all p<0.001). Patients with IgM binding to sulphatide (5% of WM) had sensory axon loss; those with IgM binding to myelin associated glycoprotein (MAG) (4% of WM) had sensorimotor axon loss and demyelination. Patients with WM with IgM binding to sulphatide (p<0.005) or MAG (p<0.001) had more severe sensory axon loss than other patients with WM. Demyelination occurred in 4% of patients with WM with no IgM binding to MAG. Age related reductions in vibration sense and sural SNAP amplitudes were similar ( approximately 30%) in WM and controls.

CONCLUSIONS

Peripheral nerve symptoms and signs occur more frequently in patients with WM than controls, involve sensory modalities, and are often associated with gait disorders. IgM binding to MAG or sulphatide is associated with a further increase in the frequency and severity of peripheral nerve involvement. Age related changes, similar to those in controls, add to the degree of reduced nerve function in patients with WM.