Laser Ablation Saturated Absorption Spectroscopy (LA-SAS) for In Situ Detection of Neodymium Isotopes.

This study introduces a novel optical system integrating laser ablation with saturated absorption spectroscopy (LA-SAS) for the detection of neodymium isotopes, crucial for the characterization process in nuclear forensics. Conventional methods for isotope analysis have encountered challenges, such as the inability to perform on-site detection or difficulty in distinguishing minor isotope differences. The LA-SAS system overcomes these limitations by combining pulsed laser for ablation and counter-propagated diode laser for saturated absorption, enabling preparation-free detection with enhanced spectral resolution. The analytical capability was demonstrated through the successful detection of seven neodymium isotopes (142Nd, 143Nd, 144Nd, 145Nd, 146Nd, 148Nd, and 150Nd) with a line width narrowed to 0.1 pm, significantly improving upon the resolution limit of conventional LA-based methods. In addition, quantitative analysis of isotope abundance was facilitated by evaluating the signals from saturated absorption spectra. Special attention was given to the hyperfine structure of odd isotopes, which was resolved by multiple fitting in spectra, thereby refining the accuracy of isotope quantification up to an average bias of 0.45%. The established LA-SAS system offers on-site detection capability based on LA, and also the high resolution from SAS, making it a promising method for in situ nuclear forensics. Consequently, the study enhances the academic understanding of neodymium isotopes and underscores the potential of LA-SAS in fields requiring detailed isotopic information.

Optimal Atmospheric Correction for Above-Ground Forest Biomass Estimation with the ETM+ Remote Sensor.

The reflectance of the Earth's surface is significantly influenced by atmospheric conditions such as water vapor content and aerosols. Particularly, the absorption and scattering effects become stronger when the target features are non-bright objects, such as in aqueous or vegetated areas. For any remote-sensing approach, atmospheric correction is thus required to minimize those effects and to convert digital number (DN) values to surface reflectance. The main aim of this study was to test the three most popular atmospheric correction models, namely (1) Dark Object Subtraction (DOS); (2) Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) and (3) the Second Simulation of Satellite Signal in the Solar Spectrum (6S) and compare them with Top of Atmospheric (TOA) reflectance. By using the k-Nearest Neighbor (kNN) algorithm, a series of experiments were conducted for above-ground forest biomass (AGB) estimations of the Gongju and Sejong region of South Korea, in order to check the effectiveness of atmospheric correction methods for Landsat ETM+. Overall, in the forest biomass estimation, the 6S model showed the bestRMSE's, followed by FLAASH, DOS and TOA. In addition, a significant improvement of RMSE by 6S was found with images when the study site had higher total water vapor and temperature levels. Moreover, we also tested the sensitivity of the atmospheric correction methods to each of the Landsat ETM+ bands. The results confirmed that 6S dominates the other methods, especially in the infrared wavelengths covering the pivotal bands for forest applications. Finally, we suggest that the 6S model, integrating water vapor and aerosol optical depth derived from MODIS products, is better suited for AGB estimation based on optical remote-sensing data, especially when using satellite images acquired in the summer during full canopy development.

Compensating isotope effect on molecular emission of hydroxyl and imidogen isotopologues in laser-induced plasma.

BACKGROUND: The molecular isotopologues in laser-induced plasma exhibit riddling emission behaviors in terms of wavelength, intensity, and temporal evolution of spectra due to the isotope effect. Although this phenomenon introduces uncertainty to isotope analyses based on molecular spectra, its underlying mechanism remains undisclosed. RESULTS: In this study, laser-induced breakdown spectroscopy (LIBS) is employed to identify the emission behavior of hydrogen, oxygen, and nitrogen isotopologues in a plasma plume. The goal is to discern the details of the isotope effect and mitigate resulting uncertainty. The molecular emissions of hydroxyl (OH) and imidogen (NH) were measured from plasma ablated on isotopically enriched water samples. Time-resolved detection clearly reveals distinct isotopic disparities in intensity variation and optimum gate delay, which were attributed to plasma thermo-hydrodynamics. Lighter isotopologues exhibit earlier and faster associations than their heavier counterparts due to their fast reaction rates and expansion velocities. The extent of the isotope effect hinged on plasma characteristics governed by measurement conditions. Consequently, comparing spectral intensity between molecular isotopologues cannot directly indicate the nominal isotope abundance of the sample. To address it, a compensation strategy has been devised, quantifying isotope effects through parameters like the slope and optimum delay of time-resolved detection. The approach successfully predicts nominal isotope abundance using compensated intensity ratios, with an absolute bias of less than 3 %. SIGNIFICANCE: This study not only offered fundamental insights into the isotope effect in laser-induced plasma but also proposed an alternative method for isotope quantification that circumvents complicated calibration processes.

Effects of remote ischemic preconditioning on the deformability and aggregation of red blood cells in a rat endotoxemia model.

BACKGROUND: The prevention of rheologic alterations in erythrocytes may be important for reducing sepsis-associated morbidity and mortality. Remote ischemic preconditioning (RIPC) has been shown to prevent tissue damage caused by severe ischemia and mortality resulting from sepsis. However, the effect of RIPC on erythrocytes in sepsis is yet to be determined. OBJECTIVE: To investigate the effect of RIPC on rheologic alterations in erythrocytes in sepsis. METHODS: Thirty male Sprague-Dawley rats were used in this study. An endotoxin-induced sepsis model was established by intraperitoneally injecting 20 mg/kg LPS (LPS group). RIPC was induced in the right hind limb using a tourniquet, with three 10-minute of ischemia and 10 min of reperfusion cycles immediately before the injection of LPS (RIPC/LPS group) or phosphate-buffered saline (RIPC group). The aggregation index (AI), time to half-maximal aggregation (T1/2), and maximal elongation index (EImax) of the erythrocytes were measured 8 h after injection. RESULTS: The AI, T1/2, and EImax values in the LPS and RIPC/LPS groups differed significantly from those in the RIPC group, but there were no differences between the values in the LPS and RIPC/LPS groups. CONCLUSIONS: RIPC did not prevent rheologic alterations in erythrocytes in the rat model of LPS-induced endotoxemia.

Association between change in working time arrangements and sleep disturbance.

BACKGROUND: Change in working time arrangement (WTA) can be harmful to workers' sleep and health. This study aimed to investigate the association between change in working time arrangement and sleep disturbance. METHODS: This study used data from the Fifth Korean Working Condition Survey and included 33,203 paid workers. We performed a stratified analysis by sex. After dividing the participants into 6 groups based on whether or not they experienced WTA changes, and their weekly working hours (≤40, 41-52, ≥53 hours), we calculated odds ratio (OR) using the weekly working hours ≤40 hours and with no WTA change as the reference group. RESULTS: Of the 33,203 paid workers, participants who experienced change in working time arrangement had higher prevalence of all three types of sleep disturbance symptoms (difficulty in falling asleep, waking up repeatedly during sleep, and waking up with a feeling of exhaustion and fatigue) in both sexes. Compared to the reference group at 95% confidence interval (CI), the group with change in WTA showed elevated OR values of 1.91 (95% CI: 1.73-2.11), 1.93 (95% CI: 1.74-2.14), 2.47 (95% CI: 2.26-2.71) for male workers; and 1.93 (95% CI: 1.73-2.16), 2.02 (95% CI: 1.80-2.27), 2.24 (95% CI: 2.01-2.50) for female workers, for difficulty in falling asleep, waking up repeatedly during the sleep, waking up with a feeling of exhaustion, and fatigue, respectively. CONCLUSIONS: Workers who experience change in work time arrangement show a high risk of sleep disturbance in both sexes.

Combined effect of emotional labor and job insecurity on sleep disturbance among customer service workers.

BACKGROUND: Job insecurity and emotional labor are poor job-related factors that are known to cause sleep disturbances in customer service workers. This study investigates the combined effect of emotional labor and job insecurity on sleep disturbance. METHODS: This study used data from the Fifth Korean Working Condition Survey and included 15,147 paid workers who serve customers below 65 years. We re-classified into 6 groups based on whether the degree of emotional labor increased (Rarely/Sometimes/Always) or whether job insecurity (No/Yes) was present. We performed propensity score matching for several covariates and calculated odds ratio (OR) and 95% confidence intervals (CIs) for sleep disturbance by logistic regression models using only matched subjects. RESULTS: Workers exposed to emotional labor and job insecurity had significantly higher risk for 3 dimensions of sleep disturbance (difficulty falling asleep, waking up repeatedly during the sleep, and waking up with feeling of fatigue) (OR [95% CI]: 1.44 [1.22-1.69], 1.18 [0.99-1.40], 1.52 [1.30-1.79] for emotional labor; and 2.00 [1.75-2.29], 2.20 [1.91-2.53], 1.67 [1.45-1.92] for job insecurity). Compared to those who were exposed to both emotional labor rarely and without job insecurity, when workers had both poor job factors, the OR (95% CI) for sleep disturbance for difficulty falling asleep, waking up repeatedly during the sleep, and waking up with feeling of fatigue were 3.05 (2.42-3.86), 2.89 (2.26-3.69), and 2.60 (2.06-3.29), respectively. The relative excess risk due to Interaction of job insecurity and emotional labor was significant only for difficulty falling asleep, but not the other 2 sleep disturbance dimensions. CONCLUSIONS: Customer service workers suffered from severe sleep disturbances according to the existing degree of emotional labor and job insecurity. The combined effect of both could have an additive influence on serious sleep disturbance among customer service workers.

Effects of blood flow on the antibacterial efficacy of chlorhexidine and silver sulfadiazine coated central venous catheter: A simulation-based pilot study.

BACKGROUND: Chlorhexidine and silver sulfadiazine coated central venous catheters (CSS-CVC) may cause loss of antimicrobial efficacy due to friction between the CVC surface and sheer stress caused by the blood flow. Therefore, the aim of this study was to investigate the antibacterial efficacy of CSS-CVC at various flow rates using a bloodstream model. METHODS: Each CVC was subjected to various flow rates (0.5, 1, 2, and 4 L/min) and wear-out times (0, 24, 48, 72, 96, and 120 hours), and the optical density (OD) 600 after a Staphylococcus aureus incubation test was used to determine the antibacterial effect of CSS-CVC. RESULTS: In the 0.5 L/min group, there was no significant change in the OD600 value up to 120 hours compared with the baseline OD600 value for CSS-CVC (P > .467). However, the OD600 values of CSS-CVC in the 1 L/min (P < .001) and 2 L/min (P < .001) groups were significantly reduced up to 72 hours, while that in the 4 L/min (p < 0.001) group decreased rapidly up to 48 hours. CONCLUSION: This study suggests that there is a doubt whether sufficient antibacterial function can be maintained with prolonged duration of catheter placement.

Characterization and prediction of meandering channel migration in the GIS environment: a case study of the Sabine River in the USA.

This study focused on the prediction of a 22 km meandering channel migration of the Sabine River between the states of Texas and Louisiana. The meander characteristics of 12 bends, identified from seven orthophotos taken between 1974 and 2004, were acquired in a GIS environment. Based on that earlier years' data acquisition, channel prediction was performed for the two years 1996 and 2004 using least squares estimation and linear extrapolations, yielding a satisfactory agreement with the observations (the median predicted and observed migration rates were 3.1 and 3.6 [m/year], respectively). The best-predicted migration rate was found to be associated with the longest orthophoto-recorded interval. The study confirmed that channel migration is strongly correlated with bend curvature and that the maximum migration rate of the bend corresponded to a radius of curvature [bend radius (R(C))/channel width (W(C))] of 2.5. In tight bends of a smaller radius of curvature than 1.6, secondary flow scouring near the bend apex increases bend curvature. The stability index of the dimensionless bend radius was determined to be 2.45. Overall, this study proves the effectiveness of least squares estimation with historical orthophotography for characterization of meandering channel migration.

Effect of varying external pneumatic pressure on hemolysis and red blood cell elongation index in fresh and aged blood: Randomized laboratory research.

BACKGROUND: External applied pneumatic pressure is usually used for rapid transfusion of red blood cells (RBCs). However, increased shear stress can cause increased hemolysis and decreased RBC elongation indices. Therefore, the purpose of this study was to measure the degree of hemolysis and the alteration of RBC elongation indices under varying external pressure in fresh and aged blood. METHODS: Venous blood samples were obtained from 20 healthy human volunteers. Each blood bag was divided into 2 subgroups (5 or 35 days of storage), and 5 levels of pressure were applied: 0, 150, 200, 250, and 300 mmHg. After infusion, a laboratory study was conducted. The percentages of irreversibly changed cells were evaluated using Bessis classification. RBC elongation indices were measured using a microfluidic ektacytometer. RESULTS: There were no significant differences in the percentage of irreversibly changed RBCs between the pressures of 0 and 300 mmHg. Moreover, there were no significant differences in laboratory test results or elongation indices among all levels of pressure. Irreversibly changed RBCs and hemolysis were increased depending on the storage period. CONCLUSION: Irreversible changes in RBCs did not occur as a result of external pressure. The hemolysis and elongation indices of fresh RBCs were not influenced by external pneumatic pressure up to 300 mmHg. Only the storage period affected the irreversible changes in RBCs and hemolysis. Therefore, the application of external pressure to RBCs in variously aged blood is likely to be a safe procedure.

Assessment of Coastal Ecosystem Services for Conservation Strategies in South Korea.

Despite the fact that scientific and political consideration for ecosystem services has dramatically increased over the past decade, few studies have focused on marine and coastal ecosystem services for conservation strategies. We used an ecosystem services approach to assess spatial distributions of habitat risks and four ecosystem services (coastal protection, carbon storage, recreation, and aesthetic quality), and explored the tradeoffs among them in coastal areas of South Korea. Additionally, we analyzed how the social and ecological characteristics in coastal areas interact with conservation and development policies by using this approach. We found strong negative associations between the habitat risks and ecosystem services (aquaculture, carbon storage, recreation, and aesthetic quality) across the coastal counties. Our results showed that the intensity of the habitat risks and the provision of ecosystem services were significantly different between reclamation-dominated and conservation-dominated counties, except for coastal vulnerability. A generalized linear model suggested that reclamation projects were dependent on economic efficiency, whereas demographic pressures and habitat conditions influenced the designation of protected areas at a county level. The ecosystem services approach provided guidelines to achieve both sustainable development and environment conservation. By using the approach, we can select the priority areas for developments while we can minimize the degradation of biodiversity and ecosystem services. As cultural ecosystem services are evenly distributed throughout coastal areas of South Korea, decision makers may employ them to improve the conditions of coastal wetlands outside of protected areas.

The Effect of Particle Size on Thermal Conduction in Granular Mixtures.

Shredded rubber tire is a geomaterial that is potentially useful in environmental and engineering projects. Here, we study the effect of particle size ratio on the thermal conductivity of granular mixtures containing rubber tire particles. Glass beads were mixed at various volume fractions with rubber particles of varying size. The 3D network model analysis using synthetic packed assemblies was used to determine the dominant factors influencing the thermal conduction of the mixtures. Results present that mixtures with varying size ratios exhibit different nonlinear evolutions of thermal conductivity values with mixture fractions. In particular, mixtures with large insulating materials (e.g., rubber particles) have higher thermal conduction that those with small ones. This is because the larger insulating particles allow better interconnectivity among the conductive particles, thereby avoiding the interruption of the thermal conduction of the conductive particles. Similar tests conducted with natural sand corroborate the significant effect of the relative size of the insulating particles. The 3D network model identifies the heterogeneity of local and effective thermal conductivity and the influence of connectivity among conductive particles. A supplementary examination of electrical conductivity highlights the significance of local and long-range connectivity on conduction paths in granular mixtures.

The regulation by phenolic compounds of soil organic matter dynamics under a changing environment.

Phenolics are the most abundant plant metabolites and are believed to decompose slowly in soils compared to other soil organic matter (SOM). Thus, they have often been considered as a slow carbon (C) pool in soil dynamics models. Here, however, we review changes in our concept about the turnover rate of phenolics and quantification of different types of phenolics in soils. Also, we synthesize current research on the degradation of phenolics and their regulatory effects on decomposition. Environmental changes, such as elevated CO2, warming, nitrogen (N) deposition, and drought, could influence the production and form of phenolics, leading to a change in SOM dynamics, and thus we also review the fate of phenolics under environmental disturbances. Finally, we propose the use of phenolics as a tool to control rates of SOM decomposition to stabilize organic carbon in ecosystems. Further studies to clarify the role of phenolics in SOM dynamics should include improving quantification methods, elucidating the relationship between phenolics and soil microorganisms, and determining the interactive effects of combinations of environmental changes on the phenolics production and degradation and subsequent impact on SOM processing.

Epidural dexamethasone decreased inflammatory hyperalgesia and spinal cPLA2 expression in a rat formalin test.

PURPOSE: The aim of this study was to investigate the effect of epidural dexamethasone on analgesia and cytosolic phospholipase A2 (cPLA2) expression in the spinal cord in a rat formalin test. MATERIALS AND METHODS: Epidural dexamethasone injection was performed to Sprague-Dawley rats with a 25 gauge needle under fluoroscopy. Following the epidural injection, a formalin induced pain behavior test was performed. Next, the spinal cords corresponding to L4 dorsal root ganglion was extracted to observe the cPLA2 expression. RESULTS: There were no differences in pain response during phase I among the groups. The phase II pain response in 300 µg of epidural dexamethasone group decreased as compared to control, 30 µg of epidural dexamethasone, 100 µg of epidural dexamethasone, and 300 µg of systemic dexamethasone groups. The expression of cPLA2 decreased in Rexed laminae I-II in 300 µg of the epidural dexamethasone group compared with the ones in the control group. CONCLUSION: Taken together, these results suggest that 300 µg of epidural dexamethasone has an attenuating effect on the peripheral inflammatory tissue injury induced hyperalgesia and this effect is mediated through the inhibition of intraspinal cPLA2 expression and the primary site of action is the laminae I-II of the spinal cord.

The Marker State Space (MSS) method for classifying clinical samples.

The development of accurate clinical biomarkers has been challenging in part due to the diversity between patients and diseases. One approach to account for the diversity is to use multiple markers to classify patients, based on the concept that each individual marker contributes information from its respective subclass of patients. Here we present a new strategy for developing biomarker panels that accounts for completely distinct patient subclasses. Marker State Space (MSS) defines "marker states" based on all possible patterns of high and low values among a panel of markers. Each marker state is defined as either a case state or a control state, and a sample is classified as case or control based on the state it occupies. MSS was used to define multi-marker panels that were robust in cross validation and training-set/test-set analyses and that yielded similar classification accuracy to several other classification algorithms. A three-marker panel for discriminating pancreatic cancer patients from control subjects revealed subclasses of patients based on distinct marker states. MSS provides a straightforward approach for modeling highly divergent subclasses of patients, which may be adaptable for diverse applications.

Serum biomarker profiles as diagnostic tools in lung cancer.

BACKGROUND: Computed tomography (CT) scanning has emerged as an effective means of early detection for lung cancer. Despite marked improvement over earlier methodologies, the low level of specificity demonstrated by CT scanning has limited its clinical implementation as a screening tool. A minimally-invasive biomarker-based test that could further characterize CT-positive patients based on risk of malignancy would greatly enhance its clinical efficacy. METHODS: We performed an analysis of 81 serum proteins in 92 patients diagnosed with lung cancer and 172 CT-screened control individuals. We utilize a series of bioinformatics algorithms including Metropolis-Monte Carlo, artificial neural networks, Naïve Bayes, and additive logistic regression to identify multimarker panels capable of discriminating cases from controls with high levels of sensitivity and specificity in distinct training and independent validation sets. RESULTS: A three-biomarker panel comprised of MIF, prolactin, and thrombospondin identified using the Metropolis-Monte Carlo algorithm provided the best classification with a %Sensitivity/Specificity/Accuracy of 74/90/86 in the training set and 70/93/82 in the validation set. This panel was effective in the classification of control individuals demonstrating suspicious pulmonary nodules and stage I lung cancer patients. CONCLUSIONS: The selected serum biomarker panel demonstrated a high diagnostic utility in the current study and performance characteristics which compare favorably with previous reports. Further advancements may lead to the development of a diagnostic tool useful as an adjunct to CT-scanning.

A case of right atrial aneurysm incidentally found in old age.

Right atrial aneurysm is a rare abnormality of unknown origin. Approximately half of patients with right atrial aneurysm show no symptoms. Right atrial aneurysm is usually detected by chance at any time between fetal and adult life and can be associated with atrial arrhythmia and systemic embolism. The diagnosis of right atrial aneurysm can be established with echocardiography, computed tomography (CT) or magnetic resonance imaging (MRI). Because of thromboembolic risk, aneurysmectomy is usually recommended. We review the case report of a 69-year-wold woman with right atrial appendiceal aneurysm, whose diagnosis was established by echocardiography and CT angiography.

A case of aortopulmonary fistula caused by a huge thoracic aortic aneurysm.

Aortopulmonary fistula is an uncommon but often fatal condition resulting as a late complication of an aortic aneurysm. The most common cause is erosion of a false aneurysm of the descending thoracic aorta into the pulmonary artery, resulting in the development of a left-to-right shunt and leading to acute pulmonary edema and right heart failure. We report an our experience with aortopulmonary fistula as a rare complication associated with thoracic aortic aneurysm and high output heart failure.