During the Fire Laboratory at Missoula Experiments (FLAME), we studied the physical, chemical, and optical properties of biomass burning smoke from the laboratory combustion of various wildland ...fuels. A good understanding of these properties is important in determining the radiative effects of biomass burning aerosols, with impacts on both local and regional visibility and global climate. We measured aerosol size distributions with two instruments: a differential mobility particle sizer (DMPS) and an optical particle counter (OPC). Volume size distributions from different burns varied from monomodal to multimodal, with geometric mean diameters ranging from 0.20–0.57 μm and geometric standard deviations ranging from 1.68–2.97. By reconciling the differences between the two sizing instruments, we estimated aerosol effective refractive indices with values ranging from 1.41 to 1.61. We reconstructed aerosol chemical composition for each burn using data from filters collected and analyzed with the Interagency Monitoring of Protected Visual Environments (IMPROVE) samplers and protocols. Aerosols were generally comprised of carbon with organic species accounting for the largest mass fraction in most cases. We used composition data to calculate aerosol density, which ranged from 1.22–1.92 g cm−3, and real and imaginary refractive indices, which had ranges of 1.55–1.80 and 0.01–0.50 respectively. Aerosol physical, chemical, and optical characterizations were combined to calculate dry mass scattering (MSE) and absorption (MAE) efficiencies at 532 nm. These parameters had values between 1.6–5.7 m2 g−1 and 0.04–0.94 m2 g−1.
The emissions of NOx (defined as NO (nitric oxide) + NO2 (nitrogen dioxide)) and hydrogen cyanide (HCN), per unit amount of fuel burned, from fires in the pine forests that dominate the mountains ...surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burning. The ammonia (NH3) emissions are about average for forest burning. The upper limit for the mass ratio of NOx to volatile organic compounds (VOC) for these MC-area mountain fires was approximately 0.38, which is similar to the NOx/VOC ratio in the MC urban area emissions inventory of 0.34, but much larger than the NOx/VOC ratio for tropical forest fires in Brazil (approximately 0.068). The nitrogen enrichment in the fire emissions may be due to deposition of nitrogen-containing pollutants in the outflow from the MC urban area. This effect may occur worldwide wherever biomass burning coexists with large urban areas (e.g. the tropics, southeastern US, Los Angeles Basin). The molar emission ratio of HCN to carbon monoxide (CO) for the mountain fires was 0.012±0.007, which is 2-9 times higher than widely used literature values for biomass burning. The ambient molar ratio HCN/CO in the MC-area outflow is about 0.003±0.0003. Thus, if only mountain fires emit significant amounts of HCN, these fires may be contributing about 25% of the CO production in the MC-area (approximately 98-100 W and 19-20 N). Comparing the PM10/CO and PM2.5/CO mass ratios in the MC Metropolitan Area emission inventory (0.0115 and 0.0037) to the PM1/CO mass ratio for the mountain fires (0.133) then suggests that these fires could produce as much as approximately 79-92% of the primary fine particle mass generated in the MC-area. Considering both the uncertainty in the HCN/CO ratios and secondary aerosol formation in the urban and fire emissions implies that about 50±30% of the "aged" fine particle mass in the March 2006 MC-area outflow could be from these fires.
Introduction
Straightlining, or identical responses across all items within a multi‐item scale, is often taken as an indication that responses to all items in a questionnaire are of poor quality. The ...purpose of this study was to examine straightlining on two scales: The Sense of Unity Scale (SUS) and the short version of the Warwick‐Edinburgh Mental Well‐being Scale (SWEMWBS).
Methods
Data stem from the 2017–2018 data collections in four Nordic countries of the Health Behaviour in School‐children study (HBSC) (15‐year‐old students only; 50.9% girls; n = 5928). Data were weighted to adjust for oversampling of Swedish‐speaking Finnish students and to equalize sample size across countries. The main analyses were done with general linear modeling with adjustments for cluster effects (school classes).
Results
The proportion with straightlining on SUS was 22.8%, varying from 5.8% among Swedish girls to 46.4% among Finnish boys. The proportion with straightlining on SWEMWBS was 18.4%, varying from 5.2% among Norwegian girls to 46.0% among Finnish boys. Straightlining on one of the scales correlated with straightlining on the other one. Straightlining tended to inflate Cronbach's α values and reduce number of factors in factor analyses. Associations between the two scales and external variables tended to be lower among straightlining students. Associations between external variables (other than SUS/SWEMWBS) are on average slightly weaker among straightliners. Straightlining students obtained more favorable scores on several resource‐related variables.
Conclusion
Although some problems have been identified, straightlining does not serve well as a general indicator of poor data quality.
Reasons for participating in physical activity (PA) may have changed in accordance with the general modernization of society. The aim is to examine changes in self‐reported reasons for liking ...leisure‐time physical activity (LTPA) and their association with self‐reported LTPA over a 20‐year period. Data were collected among nationally representative samples of 13‐year‐olds in Finland, Norway, and Wales in 1986 and 2006 (N = 9252) as part of the WHO cross‐national Health Behaviour in School‐aged Children (HBSC) study. Univariate ANOVAs to establish differences according to gender, year, and country were conducted. In all countries, 13‐year‐olds in 2006 tended to report higher importance in terms of achievement and social reasons than their counterparts in 1986, while changes in health reasons were minor. These reasons were associated with LTPA in a similar way at both time points. Health reasons for liking LTPA were considered most important, and were the strongest predictor of LTPA. The findings seem robust as they were consistent across countries and genders. Health education constitutes the most viable strategy for promoting adolescents' motivation for PA, and interventions and educational efforts could be improved by an increased focus on LTPA and sport as a social activity.
Vibro-acoustic tissue mammography Fatemi, M.; Wold, L.E.; Alizad, A. ...
IEEE transactions on medical imaging,
2002-Jan., 2002, 2002-Jan, 2002-01-00, 20020101, Letnik:
21, Številka:
1
Journal Article
Odprti dostop
A novel method for detection and imaging of microcalcifications in breast tissue is presented. The method, called vibro-acoustography, uses the radiation force of ultrasound to vibrate tissue at low ...(kHz) frequency and utilizes the resulting response to produce images that are related to the hardness of the tissue. The method is tested on human breast tissues. The resulting vibro-acoustographic images are in agreement with corresponding X-ray mammography images of the specimens. The existence of microcalcifications in locations indicated by vibro-acoustography is confirmed by histology. Microcalcifications as small as 110 /spl mu/m in diameter are detected by this method. Resulting vibro-acoustographic images show microcalcifications with high contrast with respect to the background soft tissue. Structures such as dense sclerotic tissue do not seem to interfere with detection of microcalcifications.
Background: Metaplastic breast cancer is a rare disease with little information available to guide therapy. The goals of this study were to describe the patient characteristics, systemic therapies ...and clinical outcomes of all patients with primary metaplastic breast cancer treated at Mayo Clinic between 1976 and 1997. Patients and methods: Patients were identified through the medical index of Mayo Clinic. Clinical information was abstracted from the medical record of each patient. A literature search using MEDLINE and CANCERLIT for the years 1966-1997 was performed to identify all previously reported case series in the English language containing 10 or more patients. Results: Twenty-seven patients were identified with a median age at diagnosis of 59 years (range 39–90 years). The median tumor size was 3.4 cm (range 0.5–7.0 cm). One patient had metastatic disease at presentation. Twenty-three patients had information available on nodal status, estrogen receptor (ER) and progesterone receptor (PR) status. Twenty patients (87%) were node-negative and three patients (13%) were both ER and PR positive. Disease-free survival (DFS) and overall survival (OS) were assessed for those who presented with local-regional disease. The three-year DFS was 40% (95% CI: 23%-73%) and the three-year OS was 71% (95% CI: 51%-97%). In univariate analysis, those patients 60 years of age or older at diagnosis were found to have an increased DFS (P = 0.011). Among those with prior estrogen use, both DFS (P = 0.022) and OS (P = 0.003) were decreased. Thirteen patients (50%) developed metastases with a median DFS time of 2.4 years. Ten different chemotherapy regimens were utilized for metastatic disease and one partial response was observed. There were no responses to tamoxifen in four patients with metastatic disease. Median survival after the development of metastases was eight months. Conclusions: Despite presenting more commonly as node-negative disease, DFS and OS in metaplastic breast cancer is decreased compared to typical adenocarcinomas. Systemic therapy also appears to be less effective. Patients with metaplastic breast cancer, particularly those with metastatic disease could be appropriate candidates for innovative therapeutic regimens.
X-ray mammography is the principal modality used today for detection of breast microcalcifications and breast lesions associated with breast cancer. X-ray mammography, however, is ionizing and its ...sensitivity is greatly reduced in dense breasts. Hence, alternative noninvasive and nonionizing breast imaging tools that can aid physicians to better diagnose early-stage breast lesions are of great interest. Vibro-acoustography is a novel noninvasive imaging technique that uses ultrasound in a fundamentally new way. This method uses the radiation force of ultrasound to vibrate the tissue at low (kilohertz) frequency and records the resulting response to produce images that are related to the mechanical properties of the tissue. The goal of this study is to evaluate the performance of vibro-acoustography in detecting breast microcalcifications by conducting vibro-acoustography on 74 fixed breast tissue samples with known microcalcifications based on their radiographs. The results indicate that in most cases micro-calcifications can be detected by vibro-acoustography. Further development of vibro-acoustography may lead to a novel-imaging tool for in vivo detection of microcalcifications.
Mesenchymal stem cells (MSCs) have the potential to replace infarct scar, but the long-term effects are unknown. We studied short- and long-term effects of MSC transplantation on left ventricular ...(LV) function in a rat myocardial infarction model.
Saline (n=46) or MSCs labeled with 1,1'-dioctadecyl-3,3,3'3'-testramethylindocarbocyanine perchlorate (DiI; n=49, 2x10(6) cells each) were injected into the scar of a 1-week-old myocardial infarction in Fischer rats. The presence and differentiation of engrafted cells and their effect on LV ejection fraction was assessed. At 4 weeks, LV stroke volume was significantly greater in the MSC-treated group (145+/-9 microL) than in the saline group (122+/-3 microL, P=0.032), and LV ejection fraction was significantly greater in MSC-treated animals (43.8+/-1.0%) than in the saline group (38.8+/-1.1%, P=0.0027). However, at 6 months, these benefits of MSC treatment were lost. DiI-positive cells were observed in the MSC group at 2 weeks and at 3 and 6 months. Expression of the muscle-specific markers alpha-actinin, myosin heavy chain, phospholamban, and tropomyosin was not observed at 2 weeks in DiI-positive cells. At 3 and 6 months, the DiI-positive cells were observed to express the above muscle-specific markers, but they did not fully evolve into an adult cardiac phenotype. Some of the DiI-positive cells expressed von Willebrand factor.
Allogeneic MSCs survive in infarcted myocardium as long as 6 months and express markers that suggest muscle and endothelium phenotypes. MSCs improved global LV function at 4 weeks; however, this benefit was transient, which suggests a possible early paracrine effect.
Vibro-acoustography is a recently developed imaging method based on the dynamic response of to low-frequency vibration produced by of ultrasound radiation force. The main differentiating feature of ...this method is that the image includes information about the dynamic properties of the object at the frequency of the vibration, which is normally much lower than the ultrasound frequency. Such information is not available from conventional ultrasound imaging. The purpose of this study is to evaluate the performance of vibro-acoustography in imaging mass lesions in soft tissue. Such lesions normally have elastic properties that are different from the surrounding tissue. Here, we first present a brief formulation of image formation in vibro-acoustography. Then we study vibro-acoustography of solid masses through computer simulation and in vitro experiments. Experiments are conducted on excised fixed liver tissues. Resulting images show lesions with enhanced boundary and often with distinctive textures relative to their background. The results suggest that vibro-acoustography maybe a clinically useful imaging modality for detection of mass lesions.
Patients with long-standing, severe, erosive rheumatoid arthritis who have extra-articular manifestations and have undergone joint replacement surgery are at increased risk for serious infection and ...premature mortality. New therapies, including cytokine antagonists, hold great promise for improving the course of rheumatoid arthritis. However, they have powerful anti-inflammatory effects that may mask symptoms of serious infection. We report a case of fatal pneumococcal sepsis occurring in a 37-year-old woman with rheumatoid arthritis treated with the tumor necrosis factor antagonist etanercept and suggest management strategies for early detection and management of this complication.
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