Free-standing, thin-film sensors for the trace detection of explosives.

In a world focused on the development of cybersecurity, many densely populated areas and transportation hubs are still susceptible to terrorist attacks via improvised explosive devices (IEDs). These devices frequently employ a combination of peroxide based explosives as well as nitramines, nitrates, and nitroaromatics. Detection of these explosives can be challenging due to varying chemical composition and the extremely low vapor pressures exhibited by some explosive compounds. No electronic trace detection system currently exists that is capable of continuously monitoring both peroxide based explosives and certain nitrogen based explosives, or their precursors, in the vapor phase. Recently, we developed a thermodynamic sensor that can detect a multitude of explosives in the vapor phase at the parts-per-trillion (ppt) level. The sensors rely on the catalytic decomposition of the explosive and specific oxidation-reduction reactions between the energetic molecule and metal oxide catalyst; i.e. the heat effects associated with catalytic decomposition and redox reactions between the decomposition products and catalyst are measured. Improved sensor response and selectivity were achieved by fabricating free-standing, ultrathin film (1 µm thick) microheater sensors for this purpose. The fabrication method used here relies on the interdiffusion mechanics between a copper (Cu) adhesion layer and the palladium (Pd) microheater sensor. A detailed description of the fabrication process to produce a free-standing 1 µm thick sensor is presented.

Sensors for the detection of ammonia as a potential biomarker for health screening.

The presence of ammonia within the body has long been linked to complications stemming from the liver, kidneys, and stomach. These complications can be the result of serious conditions such as chronic kidney disease (CKD), peptic ulcers, and recently COVID-19. Limited liver and kidney function leads to increased blood urea nitrogen (BUN) within the body resulting in elevated levels of ammonia in the mouth, nose, and skin. Similarly, peptic ulcers, commonly from H. pylori, result in ammonia production from urea within the stomach. The presence of these biomarkers enables a potential screening protocol to be considered for frequent, non-invasive monitoring of these conditions. Unfortunately, detection of ammonia in these mediums is rather challenging due to relatively small concentrations and an abundance of interferents. Currently, there are no options available for non-invasive screening of these conditions continuously and in real-time. Here we demonstrate the selective detection of ammonia using a vapor phase thermodynamic sensing platform capable of being employed as part of a health screening protocol. The results show that our detection system has the remarkable ability to selectively detect trace levels of ammonia in the vapor phase using a single catalyst. Additionally, detection was demonstrated in the presence of interferents such as carbon dioxide (CO2) and acetone common in human breath. These results show that our thermodynamic sensors are well suited to selectively detect ammonia at levels that could potentially be useful for health screening applications.

Radiation plus Procarbazine, CCNU, and Vincristine in Low-Grade Glioma.

BACKGROUND: Grade 2 gliomas occur most commonly in young adults and cause progressive neurologic deterioration and premature death. Early results of this trial showed that treatment with procarbazine, lomustine (also called CCNU), and vincristine after radiation therapy at the time of initial diagnosis resulted in longer progression-free survival, but not overall survival, than radiation therapy alone. We now report the long-term results. METHODS: We included patients with grade 2 astrocytoma, oligoastrocytoma, or oligodendroglioma who were younger than 40 years of age and had undergone subtotal resection or biopsy or who were 40 years of age or older and had undergone biopsy or resection of any of the tumor. Patients were stratified according to age, histologic findings, Karnofsky performance-status score, and presence or absence of contrast enhancement on preoperative images. Patients were randomly assigned to radiation therapy alone or to radiation therapy followed by six cycles of combination chemotherapy. RESULTS: A total of 251 eligible patients were enrolled from 1998 through 2002. The median follow-up was 11.9 years; 55% of the patients died. Patients who received radiation therapy plus chemotherapy had longer median overall survival than did those who received radiation therapy alone (13.3 vs. 7.8 years; hazard ratio for death, 0.59; P=0.003). The rate of progression-free survival at 10 years was 51% in the group that received radiation therapy plus chemotherapy versus 21% in the group that received radiation therapy alone; the corresponding rates of overall survival at 10 years were 60% and 40%. A Cox model identified receipt of radiation therapy plus chemotherapy and histologic findings of oligodendroglioma as favorable prognostic variables for both progression-free and overall survival. CONCLUSIONS: In a cohort of patients with grade 2 glioma who were younger than 40 years of age and had undergone subtotal tumor resection or who were 40 years of age or older, progression-free survival and overall survival were longer among those who received combination chemotherapy in addition to radiation therapy than among those who received radiation therapy alone. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00003375.).

Reengineering the radiology enterprise: a summary of the 2014 Intersociety Committee Summer Conference.

The current initiative to reform health care from both a quality and a cost perspective has already had a profound impact on the radiology enterprise. We have seen a decrease in the utilization of imaging studies, a reduction in reimbursement, a declining payer mix, shrinking incomes, a proliferation of performance indices, creation of radiology mega-groups, growth of national radiology companies, and increasing turf incursions. Our cheese is clearly on the move, and we must take action to reengineer the radiology enterprise. In keeping with general health care reform, we must be patient-centric, data driven, and outcome based. We must create a radiology enterprise that adheres to the value equation of providing the highest quality health care, for the lowest possible cost, for all citizens.

Magnetic resonance imaging of traumatic brain injury: relationship of T2*SE and T2GE to clinical severity and outcome.

PRIMARY OBJECTIVES: To evaluate (1) the sensitivity of magnetic resonance imaging (MRI) T2* weighted gradient echo (GE) vs T2 weighted spin echo (SE) technology for lesion detection in traumatic brain injury (TBI) and (2) the relationship of lesion patterns to acute clinical severity and 1 year post-injury outcome measures. RESEARCH DESIGN: Comparative analysis. METHODS AND PROCEDURES: Forty-three acute rehabilitation patients with TBI were imaged utilizing T2 SE and T2* GE techniques an average of 26 days post-injury. Acute clinical severity measures, including Glasgow Coma Scale (GCS), time to follow commands (TFC) and post-traumatic amnesia (PTA) were abstracted from medical records. One-year post-injury outcome measures including Glasgow Outcome Scale (GOS), Disability Rating Scale (DRS) and the Craig Handicap Assessment and Reporting Technique--Short Form (CHART-SF) were collected as part of a comprehensive annual follow-up. MAIN OUTCOMES AND RESULTS: In comparison to T2 SE, T2* GE more frequently detected lesions in each of the cortical (p <0.0001), white matter (p <0.001), central grey (p <0.001) and brainstem (p <0.01) regions and in each of the frontal (p <0.0001), temporal (p <0.0001), parietal (p <0.001) and occipital (p <0.0001) lobes. With regards to acute clinical severity measures, T2* GE findings were the best predictors of GCS and the only significant predictors of PTA, while T2 SE findings were better predictors of TFC. For 1 year post-injury outcome measures, multivariate regression models utilizing T2 SE and T2* GE findings in combination were the best predictors of DRS and GOS and T2 SE findings alone were the best predictors of CHART-SF. CONCLUSIONS: This study demonstrates the enhanced sensitivity of T2* GE for detecting haemorrhagic lesions associated with TBI and supports a complimentary role for both T2 SE and T2* GE weighted imaging in characterizing injury severity and predicting longer-term outcomes.