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.

Microbiology of upper extremity soft tissue abscesses in injecting drug abusers

Drug injection often results in upper extremity soft tissue infections. We determined the bacteriology of soft tissue abscesses in substance abusers who inject drugs to provide guidelines for empiric antibiotic therapy. We retrospectively studied 855 patients (638 men and 217 women; mean age, 41.5 years) with a history of injecting illicit drugs and a diagnosis of an upper extremity soft tissue abscess. In the 694 patients with positive cultures the most common organism was Staphylococcus aureus, identified in 359 of 694 patients (52%). An increase in the incidence of oxacillin-resistant S. aureus over time was observed. Oxacillin-resistant S. aureus comprised 5% of S. aureus infections in 1999, 50% in 2001, 56% in 2003, and 82% in 2005. Microaerophilic streptococci were present in 37% of culture-positive cases and other anaerobes in 10%. Infections were monomicrobial in 366 of 694 patients (53%) and polymicrobial in 328 of 694 patients (47%). S. aureus is the most common pathogen in soft tissue abscesses in injecting drug abusers with an increasing incidence of oxacillin-resistant S. aureus. In addition to surgical decompression of abscesses, broad-spectrum empiric antibiotic therapy is necessary.

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.

Rehabilitation After Intramedullary Skeletal Kinetic Distractor Implantation

Adult limb lengthening occurs via distraction osteogenesis and traditionally involves use of an external fixator. Complications after placement of hardware often disrupt rehabilitative efforts and hinder patients' progress. A completely internal limb-lengthening device has been developed and increasingly used, and it may more commonly be seen by a physiatrist in consultation for postoperative rehabilitation. We present two cases of patients who underwent implantation of the intramedullary skeletal kinetic distractor and required acute inpatient rehabilitation. One patient had previously suffered a malunion deformity with a resultant limb shortening, and the second patient was born with a congenital leg-length inequality. Both patients had successful femoral intramedullary skeletal kinetic distractor implantation and were transferred for acute inpatient rehabilitation. Distraction occurred daily, based on the patient's level of physical activity in therapy, and was measured using a hand-held monitor. Both patients were successfully discharged home, without complications throughout the hospital stay. Knowledge of the theory and mechanism of action of the device is important to guide both the amount and type of therapy prescribed and to follow patient progress. We present general guidelines during the acute rehabilitation of a patient after intramedullary skeletal kinetic distractor surgery.

Modification of surface states in ultrathin films via hybridization with the substrate: a study of Ag on Ge

The Shockley surface state of Ag(111) develops unusual band dispersion relations for Ag films of decreasing thicknesses on Ge(111), as observed by angle-resolved photoemission. Its parabolic dispersion in the thick-film limit shifts toward higher binding energies and splits into multiple bands with dispersions that reflect the valence band structure of Ge including the heavy-hole, light-hole, and split-off bands. The results are explained in terms of a hybridization interaction between the Ag surface state and the Ge substrate states.

Peripheral neuropathy in an outpatient cohort of patients with Sjögren's syndrome

Peripheral neuropathy is common in patients with Sjögren's syndrome (SS), but its precise prevalence is unknown. Most prior studies were conducted at neurology or rheumatology specialty clinics and likely selected for a more severely affected population. We evaluated 22 SS patients and 10 controls for evidence of neuropathy in an outpatient setting at a regional meeting of the Sjögren's Syndrome Foundation. We performed neurological examinations and nerve conduction studies (NCSs) and measured serum antinuclear antibody (ANA) and SS-A and SS-B antibody levels. Participants filled out a questionnaire pertaining to symptoms, diagnosis, and treatment. We found that signs and symptoms related to small axons were more common in patients with SS than in controls. Complaints of painful distal paresthesias in the feet were noted in 59% of patients but in only 10% of controls, and of abnormal sweating in 41% and 0%, respectively. Examination revealed decreased pinprick sensation in 64% of patients with SS, but in only 30% of controls. Overall, 45% of the patients but none of the controls were thought to have an isolated small-fiber neuropathy. Large-fiber dysfunction (as measured by testing vibration, deep tendon reflexes, and NCSs) was similar between the two groups. We conclude that small-fiber neuropathy is common in patients with SS.

Correlation between initial and early follow-up CT perfusion parameters with endoscopic tumor response in patients with advanced squamous cell carcinomas of the oropharynx treated with organ-preservation therapy

BACKGROUND AND PURPOSE

Current organ-preservation regimens for upper aerodigestive tract squamous cell carcinoma (SCCA) require endoscopic procedures under general anesthesia to evaluate the tumor response. The purpose of our study was to determine whether CT perfusion (CTP) parameters correlate with response to induction chemotherapy as assessed by endoscopy under general anesthesia.

METHODS

Nine patients with advanced (stage 3 or 4) SCCA of the oropharynx were enrolled in a nested phase 2 prospective trial in which induction chemotherapy was used to assess the tumor response. Patients underwent direct laryngoscopy and CTP before and 3 weeks after one cycle of induction chemotherapy. The outcome variables were the surgeon's estimate of tumor volume during endoscopy with biopsy under anesthesia and CTP parameters (capillary permeability (CP), blood volume (BV), blood flow (BF), and mean transit time (MTT)). Wilcoxon rank sum analysis was used to correlate the baseline values of BF and BV with response to induction chemotherapy. Comparison of agreement between the reduction in tumor volume and change in CTP parameters was performed by using kappa estimates.

RESULTS

Seven of 9 patients demonstrated > or =50% tumor volume reduction, representing positive response to induction chemotherapy. In the responder group, the following changes in mean pre- and postinduction chemotherapy values were noted: mean BF, 114.2 mL/100 g /min (preinduction) to 45.1 mL/100 g/min (postinduction); mean BV, 5.11 mL/100 g to 3.1 mL/100 g; mean CP, 25.6 mL/100 g /min (preinduction) to 18.3 mL/100 g / min (postinduction); mean MTT, 4.9 seconds (preinduction) to 8.0 seconds (postinduction). In the nonresponder group, the following changes were noted: mean BF, 56.9 mL/100 g/min to 75.9 mL/100 g/min; mean, BV 2.7 mL/100 g to 4.71 mL/100 g; mean CP, 24.1 mL/100 g/min to 23.7 mL/100 g/min; mean MTT, 4.3 seconds to 5.34 seconds. Higher baseline (pretherapy) values of BV showed significant correlation with endoscopic tumor response (P < .05). Reduction in the BV (by >/=20%) on follow-up studies also showed substantial agreement with clinical response as assessed with endoscopy (kappa = 0.73). The agreement between decreased BF, decreased CP, and increased MTT and clinical response was fair (kappa = 0.37).

CONCLUSION

These preliminary results show that deconvolution-based CTP technique offers potential for noninvasive monitoring of response to induction chemotherapy in patients with oropharyngeal cancers. Percentage reduction of BV is significantly correlated to endoscopic response to induction chemotherapy, though we acknowledge that the data correspond to short-term outcomes and long-term durability of response cannot be established. Nevertheless, validation of the use of deconvolution CTP parameters as predictors of tumor response may permit replacement of an invasive diagnostic procedure conducted under anesthesia currently used to assess response with noninvasive perfusion CT imaging.

Controlling the thermal stability of thin films by interfacial engineering

The quantized electronic structure in Pb films on Si(111) varies substantially as the film thickness increases. The changes in electronic energy cause the thermal stability of the films to oscillate with an approximate bilayer period. The phase of the oscillations can be controlled by interfacial engineering. Comparison of Pb films prepared on Si(111) terminated by In, Au, and Pb as interfactants reveals a phase reversal. For , films made of odd numbers of atomic layers (5, 7, and 9) are more stable than the even ones. This trend is reversed for the other two cases.

Functional architecture of the mammalian striatum: mouse vascular and striosome organization and their anatomic relationships

To determine whether the general architecture of striatal vessels and mu opioid receptor-rich striosomes is similar, we investigated 3D reconstructions of coronal sections in 10 FVB mice. The sections were stained for striosomes using a mu opioid receptor antibody (MOR1). We used computerized procedures to detect striosomes and vessels and to calculate volume, number and colocalization of striosomes and vessels. The results showed a lattice-like pattern of striosomes similar to, and often surrounding, blood vessels. Furthermore, co-localization calculations suggested that the striosomes are more vascular than the matrix. Vessel volume was 5.0+/-1.3% per microm3 in striosomes versus 3.6+/-0.9%microm3 in matrix (p=0.01). The findings emphasize the probable importance of a grid- or lattice-like structure as an organizing principle of striatal anatomy and function. In addition, the greater vascularity of the striosomes compared to the matrix suggests a unique function of this compartment in relation to humoral signals and neurotropic drugs.

Comparison of injury case fatality rates in the United States and New Zealand

OBJECTIVE

To compare injury case fatality rates in the United States (US) with New Zealand (NZ) to guide future information collection, research, and evaluation.

DESIGN

Using NZ (1992-96) and US (1996-98) mortality censuses, NZ national 1992-96 hospital discharge censuses, and US 1996-98 National Hospital Discharge Survey data, the authors compared case fatality rates by mechanism and intent of injury and age group. The analysis was restricted to severe injuries (AIS> or =3).

SUBJECTS

NZ (1992-96) and US (1996-98) populations.

MAIN OUTCOME MEASURES

Ratio of case fatality rates in NZ versus the US (RCFR(NZ:US)).

RESULTS

Overall, among cases meeting the study criteria, unintentional injuries were 1.57 times more likely fatal in NZ and intentional assault injuries were 1.14 times more likely to be fatal in the US. Firearms were involved in 50% of US assaults versus 8% of NZ assaults. By mechanism, cutting/piercing injuries were 1.86, firearm injuries were 1.41, and motor vehicle injuries were 1.44 times more to be likely fatal in NZ. Natural/environmental injuries (RCFR(NZ:US) = 0.57), unintentional poisonings (RCFR(NZ:US) = 0.26), and unintentional suffocations (RCFR(NZ:US) = 0.67) were significantly more likely to be fatal in the US.

CONCLUSIONS

Possible reasons for the observed results include: differences in geography and proportion of population in rural areas, trauma system differences, road design and vehicle types, seat belt use, larger role of firearms in US assaults, coding practices, policies, and environmental factors. Disparities evoke hypotheses to test in future research that will guide priority setting and intervention.

Biochemical and immunological properties of cytokines conjugated to dendritic polymers

Here we describe a post-translational modification of SC-63032, a variant of the species restricted, multi-lineage hematopoeitic factor human interleukin-3 (hIL-3). We have made two new dendritic polymer (polyamidoamine or PAMAM dendrimers, generation 5)-SC-63032 bioconjugates. Using two distinct chemistries (one of which is novel to this work), we achieved site-specific conjugation with respect to the amino acid in the proteins ligated to the dendrimers. In both bioconjugates, conjugated cytokine maintains its ability to bind the hIL-3 alpha receptor subunit, but is significantly (about 10-fold) less potent in inducing hIL-3 dependent in vitro cell proliferation than is the free cytokine. In vivo data indicates that conjugation decreases the immunogenicity of the conjugated cytokine modestly. In the absence of pharmacokinetic or biodistribution effects associated with the bioconjugates that increase their potency in vivo (which can only be tested in a higher primate, due to the species restriction of hIL-3 and its derivatives), these immune mitigation effects may be too small to be therapeutically significant. Though unmodified PAMAM dendrimers fail to elicit an antibody response in mice, protein conjugation to dendrimers haptenizes them, and a dendrimer-specific antibody response is produced. In toto, the principal limitation of the dendrimer-cytokine bioconjugates herein is in their reduced receptor affinity and potency in vitro. Were the in vivo potency of the bioconjugates to parallel the in vitro potency of the conjugates reported here, it is likely that particular dendrimer bioconjugates could not justify their higher costs of goods relative to the parent SC-63032 molecule, though retention of SC-63032 biological activities in conjugates suggests that other cytokine-dendrimer bioconjugates may be bioactive. This is good news to the nanotechnology community, in as much as PAMAM dendrimers are among the monodisperse polymeric nanomaterials available, and these results show that they can be used successfully in conjugates to bioactive proteins.

Sensory exam with a quantitative tuning fork: rapid, sensitive and predictive of SNAP amplitude

BACKGROUND

In the standard neurologic examination, outcome measures of sensation testing are typically qualitative and subjective. The authors compared the outcome of vibratory sense evaluation using a quantitative Rydel-Seiffer 64 Hz tuning fork with qualitative vibration testing, and two other features of the neurologic evaluation, deep tendon reflexes and sensory nerve conduction studies.

METHODS

The authors studied 184 subjects, including 126 with Waldenström's macroglobulinemia and 58 controls, over the course of a weekend. Standard neurologic examinations and quantitative vibratory testing were performed. Sensory nerve action potentials (SNAP) were tested as a measure of sensory nerve function. Tests were carried out by different examiners who were blinded to the results of other testing and to clinical information other than the diagnosis of Waldenström's macroglobulinemia.

RESULTS

Quantitative vibration measurements in all body regions correlated with sural SNAP amplitudes. Quantitative vibration outcomes were more strongly related to sural SNAP results than qualitative evaluations of vibration. Quantitative vibration testing also detected a loss of sensation with increased age in all body regions tested.

CONCLUSIONS

Quantitative vibratory evaluation with Rydel-Seiffer tuning fork is rapid, has high inter- and intrarater reliability, and provides measures for evaluating changes in sensory function over time. Examinations with the quantitative tuning fork are also more sensitive and specific than qualitative vibration testing for detecting changes in sensory nerve function. Use of the quantitative tuning fork takes no more time, provides more objective information, and should replace the qualitative vibratory testing method that is now commonly used in the standard neurologic examination.

Breakup of quasiparticles in thin-film quantum wells

Quantum well states in thin films are commonly described in terms of a quasiparticle confined in a quantum box, but this single-particle picture can fail dramatically near a substrate band edge, as shown by this angle-resolved photoemission study. Atomically uniform Ag films are prepared on Ge(111) to facilitate accurate line shape and dispersion relation measurements. A quantum well peak is observed to split into two peaks near the Ge valence band edge. The unusual line shapes are shown to be due to many-body interactions and are quantitatively explained by a Green's function calculation.

Chemical tuning of metal-semiconductor interfaces

We report a study of the Schottky barrier for Pb films grown on Si surfaces terminated by various metals (Ag, In, Au, and Pb) to explore the atomic-scale physics of the interface barrier and a means to control the barrier height. Electronic confinement by the Schottky barrier results in quantum well states in the Pb films, which are measured by angle-resolved photoemission. The barrier height is determined from the atomic-layer-resolved energy levels and the line widths. A calculation based on the known interface chemistry and the electronegativity yields predicted barrier heights in good agreement with the experiment.

Transfection of airway epithelium by stable PEGylated poly-L-lysine DNA nanoparticles in vivo

DNA can be compacted using polyethylene glycol-substituted poly-L-lysine into discrete unimolecular (with respect to DNA) nanoparticles with minor diameter < 20 nm that are stable in normal saline for at least 23 months at 4 degrees C. We compared the activity of firefly luciferase in lungs of C57BL/6 mice that received 100 microg compacted plasmid in 25 microl saline (shown to be the optimal dose) via intratracheal or intranasal instillation with levels in animals given 100 microg naked plasmid or in untreated mice. Mice dosed with compacted DNA nanoparticles had peak activity of luciferase in lung at 2 days postinstillation, which declined in log-linear fashion with a half-life of 1.4 days. Luciferase activity in animals dosed with naked DNA was 200-fold less. Addition of polyethylene glycol to the complex was necessary for efficient gene transfer and animals that received DNA compacted with unmodified poly-L-lysine did not exhibit luciferase activity above background. Immunohistochemical staining for bacterial beta-galactosidase 2 days after administration of a compacted lacZ expression plasmid (n = 8) revealed expression predominantly in the dependent portions of the right lungs of mice, in alveolar and airway epithelial cells, though macrophages and sometimes endothelial cells also were transfected. No staining for beta-galactosidase was observed in uninjected animals (n = 4) or those dosed with naked lacZ plasmid (n = 7). Tissue survey for transgene expression shows expression only in lung and trachea following intranasal administration. Stable compacted DNA nanoparticles transfer exogenous genes to airway epithelium and show promise for lung gene therapy.

Thermal stability and electronic structure of atomically uniform Pb films on Si(111)

Atomically uniform Pb films are successfully prepared on Si(111), despite a large lattice mismatch. Angle-resolved photoemission measurements of the electronic structure show layer-resolved quantum well states which can be correlated with dramatic variations in thermal stability. The odd film thicknesses N = 5, 7, and 9 monolayers show sharp quantum well states. The even film thicknesses N = 6 and 8 do not, but are much more stable than the odd film thicknesses. This correlation is discussed in terms of a total energy calculation and Friedel-like oscillations in properties.

Electronic-structure dependence of the electron-phonon interaction in Ag

The linewidths of sp- and d-band derived electronic quantum-well states in thin films of Ag on Fe(100) are measured as a function of temperature to yield the electron-phonon coupling parameters. The results vary by a factor of up to 35 among the different states. The origin of these huge differences is traced to the decay path selection for the various initial states of the holes created by the photoemission process. The electron-phonon coupling parameter for the top d-band quantum-well state, 0.015+/-0.006, is the smallest ever reported.

Treatment of IgM antibody associated polyneuropathies using rituximab

OBJECTIVES

Polyneuropathies with associated serum IgM antibodies are often difficult to treat. Rituximab is a monoclonal antibody directed against the B cell surface membrane marker CD20. Rituximab eliminates B cells from the circulation, and, over time, could reduce cells producing autoantibodies. This study tested the ability of rituximab to produce changes in serum antibody titres, and improvement in strength, in patients with neuromuscular disorders and IgM autoantibodies.

METHODS

Over a period of two years, the authors evaluated changes in strength, measured by quantitative dynamometry, and concentrations of several types of serum antibodies in patients with polyneuropathies and serum IgM autoantibodies. Twenty one patients treated with rituximab were compared with 13 untreated controls.

RESULTS

Treatment with rituximab was followed by improved strength (an increase of mean (SEM) 23% (2%)of normal levels of strength), a reduction in serum IgM autoantibodies (to 43% (4%) of initial values), and a reduction in total levels of IgM (to 55% (4%) of initial values). There was no change in levels of serum IgG antibodies. There were no major side effects, even though B cells were virtually eliminated from the circulation for periods up to two years.

CONCLUSIONS

In patients with IgM autoantibody associated peripheral neuropathies, rituximab treatment is followed by reduced serum concentrations of IgM, but not IgG, antibodies, and by improvement in strength. Additional studies, with placebo controls and blinded outcome measures, are warranted to further test the efficacy of rituximab treatment of IgM associated polyneuropathies.

Myopathy with antibodies to the signal recognition particle: clinical and pathological features

OBJECTIVES

To study myopathies with serum antibodies to the signal recognition particle (SRP), an unusual, myositis specific antibody associated syndrome that has not been well characterised pathologically.

METHODS

Clinical, laboratory, and myopathological features were evaluated in seven consecutive patients with a myopathy and serum anti-SRP antibodies, identified over three years. The anti-SRP myopathy was compared with myopathology in other types of inflammatory and immune myopathies.

RESULTS

The patients with anti-SRP antibodies developed weakness at ages ranging from 32 to 70 years. Onset was seasonal (August to January). Weakness became severe and disability developed rapidly over a period of months. Muscle pain and fatigue were present in some patients. No patient had a dermatomyositis-like rash. Serum creatine kinase was very high (3000 to 25 000 IU/l). Muscle biopsies showed an active myopathy, including muscle fibre necrosis and regeneration. There was prominent endomysial fibrosis, but little or no inflammation. Endomysial capillaries were enlarged, reduced in number, and associated with deposits of the terminal components of complement (C5b-9, membrane attack complex). Strength improved in several patients after corticosteroid treatment.

CONCLUSIONS

Myopathies associated with anti-SRP antibodies may produce severe and rapidly progressive weakness and disability. Muscle biopsies show active myopathy with pathological changes in endomysial capillaries but little inflammation. Corticosteroid treatment early in the course of the illness is often followed by improvement in strength. In patients with rapidly progressive myopathies and a high serum creatine kinase but little inflammation on muscle biopsy, measurement of anti-SRP antibodies and pathological examination of muscle, including evaluation of endomysial capillaries, may provide useful information on diagnosis and treatment.

HARM 2000: crash cost and consequence data for the new millennium

This paper presents the most detailed and current costs per US motor vehicle crash victim. These unit costs, which include the first keyed to AIS90, are reported by category, body part, whether a fracture/dislocation was involved, and MAIS. This level of detail allows for reliable analyses of interventions targeting narrow ranges of injuries and, hopefully, for the development of a biomechanical injury cost model.

Large electron-phonon coupling at an interface

The strength of electron-phonon coupling in atomically uniform films of Ag on Fe is determined by angle-resolved photoemission from quantum well states in these films over a wide temperature range. As the film thickness is reduced, contributions from the surface and interface should become more important, and, experimentally, a large enhancement with superimposed quantum oscillations is observed. An analysis of the quantum oscillations indicates that this large enhancement is an interface effect.

Electron-hole coupling and the charge density wave transition in TiSe2

Angle-resolved photoemission is employed to measure the band structure of TiSe2 in order to clarify the nature of the ( 2 x 2 x 2) charge density wave transition. The results show a very small indirect gap in the normal phase transforming into a larger indirect gap at a different location in the Brillouin zone. Fermi surface topology is irrelevant in this case. Instead, electron-hole coupling together with a novel indirect Jahn-Teller effect drives the transition.

How successfully do general practitioners diagnose herpetic gingivo-stomatitis clinically?

Herpetic gingivo-stomatitis is a common, often painful affliction of young children. Recently, aciclovir treatment has been found to be effective in hospital-referred cases, an approach limited in general practice where laboratory diagnosis is invariably impractical. This study demonstrated that 49 out of 63 clinical diagnoses of herpetic gingivo-stomatitis [PPV = 78%] made by 27 GPs were subsequently validated by laboratory virus culture. This suggests that herpetic gingivo-stomatitis might be treated with aciclovir in general practice on the basis of a clinical diagnosis alone.

New experimental limits on strongly interacting massive particles at the TeV scale

We have carried out a search for strongly interacting massive particles (SIMPs) bound to Au and Fe nuclei, which could manifest themselves as anomalously heavy isotopes of these elements. Our samples included gold from the NASA Long Duration Exposure Facility satellite, RHIC at Brookhaven National Laboratory, and from various geological sources. We find no evidence for SIMPs in any of our samples, and our results set stringent limits (as low as approximately 10(-12)) on the abundances of anomalous Au or Fe isotopes with masses up to 1.67 and 0.65 TeV/c(2), respectively.