Hot electron plasmon-protected solar cell.

A solar cell based on a hot electron plasmon protection effect is proposed and made plausible by simulations, non-local modeling of the response, and quantum mechanical calculations. In this cell, a thin-film, plasmonic metamaterial structure acts as both an efficient photon absorber in the visible frequency range and a plasmonic resonator in the IR range, the latter of which absorbs and protects against phonon emission the free energy of the hot electrons in an adjacent semiconductor junction. We show that in this structure, electron-plasmon scattering is much more efficient than electron-phonon scattering in cooling-off hot electrons, and the plasmon-stored energy is recoverable as an additional cell voltage. The proposed structure could become a prototype of a new generation of high efficiency solar cells.

Nanoscope based on nanowaveguides.

The far field spatial resolution of conventional optical lenses is of the order of the wavelength of light, due to loss in the far field of evanescent, near electromagnetic field components. We show that subwavelength details can be restored in the far field with an array of divergent nanowaveguides, which map the discretized, subwavelength image of an object into a magnified image observable with a conventional optical microscope. We demonstrate in simulations that metallic nanowires, nanocoaxes, and nanogrooves can be used as such nanowaveguides. Thus, an optical microscope capable of subwavelength resolution - a nanoscope - can be produced, with possible applications in a variety of fields where nanoscale optical imaging is of value.

The suspected scaphoid injury: resource implications in the absence of magnetic resonance imaging.

INTRODUCTION: Undiagnosed and untreated scaphoid fractures have poorer outcomes and many patients are unnecessarily immobilised for prolonged periods of time to avoid missing occult injuries. Magnetic resonance imaging has a high sensitivity and specificity in detecting occult scaphoid fractures, but many units do not routinely use this imaging modality in the diagnostic pathway. We aimed to determine the patterns of suspected scaphoid injuries, report the process of care, and calculate the costs involved in their management. METHODS: We prospectively identified all adult patients referred to fracture clinic at the Royal Infirmary of Edinburgh with a scaphoid-related injury, between October 2007 and September 2008. Clinical notes were examined retrospectively. We defined three injury groups: true fractures, occult fractures, and suspected scaphoid injuries. We analysed patient demographics, treatment timelines, and the treatment costs involved. RESULTS: Fracture clinic received 537 scaphoid-related referrals. There were 87 true fractures, 43 occult fractures, and 407 suspected injuries, incurring average treatment costs of £1,173, £773, and £384 respectively. Occult fractures accounted for 33% of all confirmed scaphoid fractures. The majority of scaphoid-related referrals (76%) were never proven to have a scaphoid fracture, and many were unnecessarily immobilised. The costs involved in the treatment of suspected scaphoid injuries were found to be higher than the cost of magnetic resonance imaging (£97). CONCLUSION: In this group of suspected scaphoid injury, we believe the introduction of an early magnetic resonance imaging protocol would lead to an earlier definitive diagnosis and potentially a more cost-effective service.

Suppression of crosstalk in multielectrode arrays with local shielding.

Electrical crosstalk can constrain the performance of multielectrode arrays in electro- and neurophysiology, in terms of both stimulation and recording. This is especially so at high electrode density, desirable for spatiotemporal mapping of bioelectrical signals from multiple cells. Channel interference due to crosstalk is currently only partially addressed, via continuous interleaved sampling or post-data acquisition spike sorting. Here, we show that a locally-shielded electrode architecture significantly suppresses crosstalk, and enables multi-site recording at high electrode density without the need for spike sorting. Arrays of shielded electrodes, prepared by micro- and nanofabrication techniques in a vertically-oriented coaxial geometry, demonstrate at least a 400 times improvement in spatial density over the unshielded case.

An extended core nanocoax pillar architecture for enhanced molecular detection.

Biosensors that incorporate nanomaterials and nanofabrication techniques enable molecular detection of chemical and biological macromolecules with a high degree of specificity and ultrasensitivity. Here, we present a novel fabrication process that yields a nanostructure capable of detecting biological macromolecules. The extended core nanocoax (ECC) structure builds on a previously reported nanocoaxial-based sensor. The fabrication of the device incorporates an extended inner pillar, with controllable extension above the annulus and into the surrounding solution. This new design eliminates structural constraints inherent in the original nanocoax architecture. We also provide results demonstrating improvement in biosensing capability. Specifically, we show the capability of the new architecture to detect the B subunit of the Vibrio cholerae toxin at improved sensitivity (100 pg/ml) in comparison to optical enzyme-linked immunosorbant assay (1 ng/ml) and previously reported coaxial nanostructures (2 ng/ml).

Women's health measures in two North Carolina regions sampled from the Basic Automated Birth Yearbook (BABY) datasets: experimental findings, methodological limits and future directions.

PURPOSE: To compare selected characteristics in two North Carolina counties to document women's health services at the geographical extremes of the state. METHODS: Using aggregated 2004 data obtained from the North Carolina State Center for Health Statistics, obstetric and perinatal characteristics were experimentally analyzed for the westernmost and easternmost counties in North Carolina (Cherokee and Dare County, respectively). FINDINGS: During the experiment period, 489 infants were delivered in Dare County (population 33,518), while 259 births were recorded in Cherokee County (population 25,289). Prenatal care was established by most women in both counties by the second gestational month. Women in Cherokee County were younger and less educated at delivery than women in Dare County, and smoking prevalence was higher in Cherokee County than in Dare County (31.3% vs 12.9%; p <0.01). Cherokee County infants required assisted ventilation and other medical interventions more often than babies born in Dare County (p <0.01) yet significantly fewer cesarean deliveries were performed in Cherokee County than Dare County (25.5% vs 35.2%; p = 0.04). CONCLUSION: This pilot study showed a significantly higher rate of tobacco use, and lower maternal education level in Cherokee County was associated with a higher incidence of multiple maternal complications and neonatal interventions compared to Dare County. Interestingly, the cesarean delivery rate was lower in Cherokee County despite these factors. We found < 10% of babies born in the study regions required any neonatal intervention. Early and almost universal access to prenatal care did not appear to be a problem at either site. Our preliminary comparison identified important limitations in this government-sponsored dataset that rendered logistic regression analysis methodologically impossible. Changes in process could improve surveillance based on patient-level data and facilitate multivariate analysis. Specific interventions to optimize women's health services form the basis of future experimental research, including larger regional populations.

SABRE hyperpolarisation of vitamin B3 as a function of pH.

In this work we describe how the signal enhancements obtained through the SABRE process in methanol-d4 solution are significantly affected by pH. Nicotinic acid (vitamin B3, NA) is used as the agent, and changing pH is shown to modify the level of polarisation transfer by over an order of magnitude, with significant improvements being seen in terms of the signal amplitude and relaxation rate at high pH values. These observations reveal that manipulating pH to improve SABRE enhancements levels may improve the potential of this method to quantify low concentrations of analytes in mixtures. 1H NMR spectroscopy results link this change to the form of the SABRE catalyst, which changes with pH, resulting in dramatic changes in the magnitude of the ligand exchange rates. The presented data also uses the fact that the chemical shifts of the nicotinic acids NMR resonances are affected by pH to establish that hyperpolarised 1H-based pH mapping with SABRE is possible. Moreover, the strong polarisation transfer field dependence shown in the amplitudes of the associated higher order longitudinal terms offers significant opportunities for the rapid detection of hyperpolarised NA in H2O itself without solvent suppression. 1H and 13C MRI images of hyperpolarised vitamin B3 in a series of test phantoms are presented that show pH dependent intensity and contrast. This study therefore establishes that when the pH sensitivity of NA is combined with the increase in signal gain provided for by SABRE hyperpolarisation, a versatile pH probe results.

Resting electrocardiograms as baseline tests: impact on the management of elderly patients.

PURPOSE: We evaluated management decisions of house staff in a university hospital emergency department (ED) to determine the impact of baseline electrocardiogram (ECG) results on the care of elderly patients. SUBJECTS AND METHODS: The study employed a prospective before-after research design. The subjects included internal medicine house staff assigned to the ED and the 47 elderly patients treated by them during 58 ED visits. The measures of impact on patient care included how often and in what ways comparison of baseline and ED ECG results changed the house staff's diagnostic impressions and treatment plans. To determine changes, we asked house staff to indicate their impressions and management plans before and after comparing baseline and ED ECG results. In addition, a panel of faculty members used a modification of the nominal group process to determine treatment changes and to estimate benefit to patients from the changes. RESULTS: House staff indicated that baseline ECG results led them to change diagnostic impressions during 13 (22%) and treatment plans during eight (14%) of the 58 visits. Six of the patients benefited from the treatment changes. The faculty judges indicated that baseline ECG findings would have altered their diagnostic impressions in eight (14%) and treatment decisions in three (5%) of the 58 cases, one of which would have benefited from the change. All patients for whom there were changes of impression or plan had prior histories of cardiovascular disease. CONCLUSION: We conclude that baseline ECGs provide ED house staff with diagnostic information that often leads to changes in management of elderly patients with prior histories of cardiovascular disease. Future studies should evaluate the efficacy of baseline ECGs in patients without such histories.

Usefulness of ambulatory radionuclide monitoring of left ventricular function early after acute myocardial infarction for predicting residual myocardial ischemia.

Ambulatory radionuclide monitoring of left ventricular function was performed with the nuclear Vest device in 35 patients early after acute myocardial infarction. Patients were evaluated during post-infarction treadmill, other activities that included mental stress and cold pressor challenge, and with stress thallium imaging and cardiac catheterization. Of the 35 patients evaluated, 14 had ischemic responses on treadmill testing and 21 had negative responses. By contrast, 20 had redistribution by thallium imaging suggesting ischemia. Vest studies demonstrated 56 responses suggestive of ischemia in 23 patients. Twenty-two occurred during exercise and 13 with mental stress. Seventy-five percent were silent and only 39% had associated electrocardiographic changes. Vest responses were compared in patients whose thallium scan was indicative of ischemia (thallium-positive) and those without ischemia (thallium-negative). Ejection fraction was higher in the thallium-positive group (0.52 +/- 0.11), as compared with thallium-negative patients (0.44 +/- 0.1). With exercise, ejection fraction decreased for the thallium-positive patients from 0.52 +/- 0.11 to 0.40 +/- 0.09 at peak exercise. For thallium-negative patients, ejection fraction changes were not significant. During mental stress, ejection fraction decreased from 0.51 +/- 0.11 to 0.45 +/- 0.12 for thallium-positive patients while thallium-negative patients were unchanged. Vest-measured decreases in ejection fraction of greater than or equal to 5 units during exercise were highly sensitive (90%), specific (73%) and predictive (82%) of a positive thallium scan. The same response for mental stress was specific (87%) and predictive (85%) of a positive scan result.(ABSTRACT TRUNCATED AT 250 WORDS)

Another hot tub hazard. Toxicity secondary to bromine and hydrobromic acid exposure.

We describe the clinical course of two patients who developed acute pneumonitis followed by reactive airways dysfunction syndrome after bathing in a hot tub. Additional findings were present and suggested that exposure to a corrosive agent was responsible. Bromine and hydrobromic acid generated from a widely used water disinfectant were implicated as the underlying cause. Physicians should be alert to the possibility that such exposures may initiate or exacerbate inflammatory pulmonary disease.

Wound infection associated with Vibrio alginolyticus.

A 42-year-old man had an infected ulcerated lesion of the anterior aspect of the right lower extremity. Vibrio alginolyticus was twice isolated from the lesion. Emphasis is placed on the clinical and laboratory characteristics of this organism and its differentiation from other halophilic vibrios.

Core rewarming via warm lavage liquid ventilation in a swine model of hypothermia-associated ventricular fibrillation.

OBJECTIVES: To determine whether warm lavage liquid ventilation (LV) would provide rapid cardiopulmonary rewarming in swine with severe hypothermia and ventricular fibrillation. METHODS: Intubated common swine (n = 3; mean +/- SEM weight 26+/-1.2 kg) were cooled to a mean aortic temperature of 26.4+/-0.9 degrees C. Ventricular fibrillation was induced by transthoracic electrical shock. Rewarming was initiated by continuous endotracheal instillation of warm (44 degrees C) pre-oxygenated, perfluorocarbon liquid at 5 mL/kg/min. Endotracheal instillation of perfluorocarbon occurred while standard gas ventilation continued. Manual chest compressions were performed throughout the 30-minute rewarming process. Outcome measures were the absolute and relative rates of change of all temperatures. RESULTS: After 30 minutes of warm lavage LV, the mean aortic and pulmonary artery temperatures increased by 6.6+/-0.6 degrees C, respectively. Esophageal, nasal, and rectal temperatures did not change significantly. In one animal, normal sinus rhythm spontaneously returned after 16 minutes of rewarming. CONCLUSIONS: During cardiac arrest, warm lavage liquid ventilation may produce rapid cardiopulmonary rewarming.

The value of baseline chest radiograph reports in the care of elderly patients in an emergency department.

The authors used a before/after research design to determine the impact of written reports of baseline chest radiographs (CXRs) on the care of elderly patients during 48 emergency department visits. Internal medicine housestaff completed questionnaires that included inquiries about their treatment plans for the patients both before and after they reviewed reports of baseline CXR results. The investigators compared these answers to determine the proportion of patients for whom baseline CXR reports changed patient management. In addition, three faculty reviewers used the nominal group process, a consensus analysis approach, to measure treatment changes and to estimate benefit to the patients from the alterations in management. The housestaff indicated that written baseline CXR reports caused them to change treatment plans during only 2 (4%) of the 48 visits. In both cases, they provided aggressive treatment for congestive heart failure because of baseline CXR results. The faculty reviewers could find only one case in which baseline CXR findings might have changed their management plans. Moreover, they were not convinced that the treatment changes indicated by the housestaff actually benefitted the patients. These results suggest that written reports of baseline CXRs do not improve the care of acutely ill patients in an emergency department setting.

Myocardial infarction associated with phenylpropanolamine.

Phenylpropanolamine is a sympathomimetic agent widely used in over-the-counter and prescription decongestant medications. We describe a young woman without cardiac risk factors who sustained myocardial infarction after unintentional overuse of a nasal decongestant containing phenylpropanolamine. The pathophysiology of myocardial injury and current management strategies as related to this agent are discussed. Although serious adverse reactions to phenylpropanolamine are uncommon, potentially serious harm may be caused by this widely available drug in healthy individuals.