Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models

Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring.     

Computer-Aided Diagnosis of Skin Lesions Using Conventional Digital Photography: A Reliability and Feasibility Study

Background

Computer-aided diagnosis (CADx) software that provides a second opinion has been widely used to assist physicians with various tasks. In dermatology, however, CADx has been mostly limited to melanoma or melanocytic skin cancer diagnosis. The frequency of non-melanocytic skin cancers and the accessibility of regular digital macrographs have raised interest in developing CADx for broader applications.

Objectives

To investigate the feasibility of using CADx to diagnose both melanocytic and non-melanocytic skin lesions based on conventional digital photographic images.

Methods

This study was approved by an institutional review board, and the requirement to obtain informed consent was waived. In total, 769 conventional photographs of melanocytic and non-melanocytic skin lesions were retrospectively reviewed and used to develop a CADx system. Conventional and new color-related image features were developed to classify the lesions as benign or malignant using support vector machines (SVMs). The performance of CADx was compared with that of dermatologists.

Results

The clinicians'' overall sensitivity, specificity, and accuracy were 83.33%, 85.88%, and 85.31%, respectively. New color correlation and principal component analysis (PCA) features improved the classification ability of the baseline CADx (p = 0.001). The estimated area under the receiver operating characteristic (ROC) curve (Az) of the proposed CADx system was 0.949, with a sensitivity and specificity of 85.63% and 87.65%, respectively, and a maximum accuracy of 90.64%.

Conclusions

We have developed an effective CADx system to classify both melanocytic and non-melanocytic skin lesions using conventional digital macrographs. The system''s performance was similar to that of dermatologists at our institute. Through improved feature extraction and SVM analysis, we found that conventional digital macrographs were feasible for providing useful information for CADx applications. The new color-related features significantly improved CADx applications for skin cancer.     

Probabilistic MRI Tractography of the Optic Radiation Using Constrained Spherical Deconvolution: A Feasibility Study

Background and Purpose

Imaging the optic radiation (OR) is of considerable interest in studying diseases affecting the visual pathway and for pre-surgical planning of temporal lobe resections. The purpose of this study was to investigate the clinical feasibility of using probabilistic diffusion tractography based on constrained spherical deconvolution (CSD) to image the optic radiation. It was hypothesized that CSD would provide improved tracking of the OR compared with the widely used ball-and-stick model.

Methods

Diffusion weighted MRI (30 directions) was performed on twenty patients with no known visual deficits. Tractography was performed using probabilistic algorithms based on fiber orientation distribution models of local white matter trajectories. The performance of these algorithms was evaluated by comparing computational times and receiver operating characteristic results, and by correlation of anatomical landmark distances to dissection estimates.

Results

The results showed that it was consistently feasible to reconstruct individual optic radiations from clinically practical (4.5 minute acquisition) diffusion weighted imaging data sets using CSD. Tractography based on the CSD model resulted in significantly shorter computational times, improved receiver operating characteristic results, and shorter Meyer’s loop to temporal pole distances (in closer agreement with dissection studies) when compared to the ball-and-stick based algorithm.

Conclusions

Accurate tractography of the optic radiation can be accomplished using diffusion MRI data collected within a clinically practical timeframe. CSD based tractography was faster, more accurate and had better correlation with known anatomical landmarks than ball-and-stick tractography.     

A Feasibility Study to Monitor the Macroinvertebrate Diversity of the River Nile Using Three Sampling Methods

The River Nile is one of the world’s major rivers. Its’ catchment in Egypt has a population of 75,000,000. River flow is highly regulated and there are known discharges of pollutants. 1035 km of the river downstream of the Aswan high dam was studied to test the hypothesis that representative qualitative samples can be used to estimate macroinvertebrate biodiversity. Benthic macroinvertebrates are difficult to sample in large rivers and a reliable sampling strategy is required to evaluate their ecological status. Three methods for sampling have been investigated. Ekman Grab, macrophyte sweep netting and Artificial Substrate Samplers (ASS) were used to sample 15 sites from Aswan to Cairo between September 2001 and June 2002. Organisms were identified to species level where possible. Taxon accretion curves indicated that the all taxa present at a site should be collected using either 15 grab samples, 10 macrophyte samples or 5 ASS. The best time to sample was May–June. The biodiversity of macroinvertebrates in the Nile was recorded as 50 taxa with values of 7–31 at individual bank-side sites. Mid-stream biodiversity was much lower (0–19). Lowest biodiversity occurred at sites with known pollution inputs whilst highest occurred at sites with high levels of sedimentation. A regular programme for biomonitoring is recommended which will allow current status to be confirmed and future changes detected.     

基于LED作为照射光源的血疗法可行性研究

通过对LED在生物医学领域的应用分析发现,LED光存在与激光相类似的生物刺激效应。目前弱激光血疗已由血管内照射发展到体表照射、黏膜照射。这为LED光照射体表、黏膜实现血疗提供了良好的预期。为了证明LED光可以代替激光作为净血治疗仪的光源,本实验设计了激光与LED光对自由基损伤模型红细胞变形性作用的对比实验,结果表明,两种光照方法均对红细胞变形性有改善作用。LED相比激光安全性更好、成本更加低廉,特别适合往家用小型化方向发展。     

Preparation of Controlled-Release Fine Particles Using a Dry Coating Method

Wet coating methods use organic solvents to prepare layered particles that provide controlled-release medications. However, this approach has disadvantages in that it can cause particle agglomeration, reduce pharmaceutical stability, and leave residual organic solvents. We used a dry coating method to overcome these issues. Fine particles (less than 50 μm in diameter) of controlled-release theophylline were created using theophylline (TP; model drug), polyethylene glycol 20,000 (PEG; drug fixative), hydrogenated castor oil (HCO; controlled-release material), hydrogenated rapeseed oil (HRSO; controlled-release material), and cornstarch (CS; core particle). An ultrahigh-speed mixer was employed to mix TP and CS for 5 min at 28,000 rpm. Subsequent addition of PEG produced single-core particles with a drug reservoir coating. Addition of HCO and HRSO to these particles produced a controlled-release layer on their surface, resulting in less than 10% TP dissolution after 8 h. We successfully demonstrated that this dry coating method could be used to coat 16-μm CS particles with a drug reservoir layer and a controlled-release layer, producing multi-layer coated single-core particles that were less than 50 μm in diameter. These can be used to prepare controlled-release tablets, capsules, and orally disintegrating tablets.     

Feasibility Study of Using Centrifuge for Investigating LNAPL Migration in Unsaturated Soils

Centrifuge modeling appears potentially useful for studying geo-environmental problems such as pollutant migration in subsurface systems. In this study, the “modeling of models” technique was used to validate the feasibility of using a geotechnical centrifuge to model the transport behavior of light non-aqueous phase liquids (LNAPLs) in unsaturated soils. All the experiments were conducted to simulate a gasoline spill from a leaking underground storage tank (UST) and the subsequent subsurface migration of the gasoline. When the gravity in the centrifuge reached the desired g-level, the gasoline was released from the UST and then it migrated in the unsaturated soil corresponding to a prototype time equivalent of one year. After the centrifuge tests, soil samples were collected using sampling tubes and the concentrations of individual constituent in the LNAPL were directly measured by means of gas chromatograph analysis. Results obtained from the centrifuge tests at different g-levels show that similar migration patterns are found for LNAPL transport in unsaturated porous media. The location of the peak concentration and the behavior of lateral spreading can be adequately described. In addition, centrifuge test data show that the migration pattern of LNAPLs is related to the soil type and the physical properties of individual constituents in the LNAPLs.     

Quantification of Tumor Vessels in Glioblastoma Patients Using Time-of-Flight Angiography at 7 Tesla: A Feasibility Study

Purpose

To analyze if tumor vessels can be visualized, segmented and quantified in glioblastoma patients with time of flight (ToF) angiography at 7 Tesla and multiscale vessel enhancement filtering.

Materials and Methods

Twelve patients with newly diagnosed glioblastoma were examined with ToF angiography (TR = 15 ms, TE = 4.8 ms, flip angle = 15°, FOV = 160×210 mm², voxel size: 0.31×0.31×0.40 mm³) on a whole-body 7 T MR system. A volume of interest (VOI) was placed within the border of the contrast enhancing part on T1-weighted images of the glioblastoma and a reference VOI was placed in the non-affected contralateral white matter. Automated segmentation and quantification of vessels within the two VOIs was achieved using multiscale vessel enhancement filtering in ImageJ.

Results

Tumor vessels were clearly visible in all patients. When comparing tumor and the reference VOI, total vessel surface (45.3±13.9 mm² vs. 29.0±21.0 mm² (p<0.035)) and number of branches (3.5±1.8 vs. 1.0±0.6 (p<0.001) per cubic centimeter were significantly higher, while mean vessel branch length was significantly lower (3.8±1.5 mm vs 7.2±2.8 mm (p<0.001)) in the tumor.

Discussion

ToF angiography at 7-Tesla MRI enables characterization and quantification of the internal vascular morphology of glioblastoma and may be used for the evaluation of therapy response within future studies.     

用粪粒外部形态指标鉴定海南坡鹿的性别与年龄

利用粪便形态指标鉴定有蹄类动物的性别和年龄对研究不同性别年龄个体的生态学和性别分离具有重要价值。利用2006年3月在海南大田国家级自然保护区采集的145头(次)已知性别和年龄组的野生海南坡鹿(Cervus eldi hainanus)粪便4006粒,将坡鹿划分为成年雄鹿、成年雌鹿、亚成年雄鹿、亚成年雌鹿和幼鹿5个性别年龄组,使用逐步判别分析和聚类分析对粪粒的4项直接测度指标(干重、体积、长轴长、短轴长)以及2项间接测度指标(长短轴比和椭球形状指数)进行分析。结果表明:逐步判别分析对海南坡鹿粪粒的性别年龄组正判率为成年雄鹿76.17%、成年雌鹿42.22%、亚成年雄鹿34.94%、亚成年雌鹿40.46%、幼鹿79.34%,聚类分析的判别率为成年雄鹿19.48%、成年雌鹿20.02%、亚成年雄鹿37.37%、亚成年雌鹿42.82%、幼鹿91.50%。利用粪粒形态判别海南坡鹿的性别年龄组最可靠的是幼鹿,次之为成年雄鹿。利用粪粒形态判别海南坡鹿的性别年龄组可以应用于以取样原理进行的群体水平研究,但个体水平上的性别和年龄鉴定由于判别误差较大而难以应用。     

用粪便形态特征初步研究新疆塔里木马鹿种群年龄和性别

塔里木马鹿分布在干旱地区,是唯一的适应干旱荒漠环境的特殊马鹿亚种之一.目前,塔里木马鹿种群面临着栖息地退缩和片段化的双重影响,这不仅导致了种群数量的锐减,而且也因物种遗传漂变和近亲繁殖的不断增加,进一步加剧其濒危程度.为了有效地保护该物种,全面了解种群结构是至关重要.对塔里木马鹿粪便的长度、宽度、长度/宽度比例和体积等参数进行了测量,并采用判别分析方法划分种群年龄.结果表明,塔里木马鹿粪便形态在不同性别之间有差异,一般雌性的粪便大于雄性(P<0.05).同时根据粪便形态对种群年龄划分为成年雄性、成年雌性和幼体等3个年龄组.     

Medical Insurance Feasibility Study: A Technical Summary

There are risks of adverse outcomes to patients in the course of health care management. A study was undertaken to measure these outcomes in California for 1974. Secondary benefits of the study include new insights into the types and sources of disabilities caused by health care management and the development of new methods for carrying out generic adverse-outcome monitoring.     

A Feasibility Study of an Intravascular Imaging Antenna to Image Atherosclerotic Plaques in Swine Using 3.0 T MRI

Purpose

To investigate the feasibility of an intravascular imaging antenna to image abdominal aorta atherosclerotic plaque in swine using 3.0T magnetic resonance imaging (MRI).

Methods

Atherosclerotic model was established in 6 swine. After 8 months, swine underwent an MR examination, which was performed using an intravascular imaging guide-wire, and images of the common iliac artery and the abdominal aorta were acquired. Intravascular ultrasound (IVUS) was performed in the right femoral artery; images at the same position as for the MR examination were obtained. The luminal border and external elastic membrane of the targeted arteries were individually drawn in the MR and IVUS images. After co-registering these images, the vessel, lumen, and vessel wall areas and the plaque burden in the same lesions imaged using different modalities were calculated and compared. The diagnostic accuracy of intravascular MR examination in delineating the vessel wall and detecting plaques were analyzed and compared using IVUS.

Results

Compared with IVUS, good agreement was found between MRI and IVUS for delineating vessel, lumen, and vessel wall areas and plaque burden (r value: 0.98, 0.95, 0.96 and 0.91, respectively; P<0.001).

Conclusion

Compared with IVUS, using an intravascular imaging guide-wire to image deep seated arteries allowed determination of the vessel, lumen and vessel wall areas and plaque size and burden. This may provide an alternative method for detecting atherosclerotic plaques in the future.     

壳聚糖辐照降解产物涂膜保鲜草莓研究

壳聚糖具有抑菌性与成膜性。将壳聚糖辐照降解得到的一系列不同粘均分子量产物进行涂膜草莓保鲜,研究涂膜液中壳聚糖粘均分子量、浓度、pH值、有机酸、明胶含量对草莓保鲜效果的影响;并设计四因素三水平正交试验。实验结果表明：1％（w／v）7．0×10^4Da壳聚糖、1％（v／v）醋酸、pH5、添加明胶0．5％的涂膜配方具有最好的保鲜效果;在常温（20℃、湿度80％～90％）下可以延长贮藏期2d;低温（3℃-4℃、湿度80％-90％）下可以延长贮藏期3d。     

Enhancement of the Stability of Insoluble Calcium Particles Using a Phospholipid Coating

Calcium is one of the most important elements in the human body. Insoluble calcium particles are often used in calcium-fortified food products, such as calcium-fortified milk, dairy beverages or protein powders. However, their suspension may be unstable often leading to precipitation in such products. In this study, three different kinds of insoluble calcium particles, i.e. hydroxyapatite (HA), tricalcium phosphate (TCP) and calcium carbonate (CaCO₃) were coated with amphiphilic phospholipids using a solvent-exchange method. Suspension stability of these insoluble calcium particles was effectively improved with phospholipid coating, especially for HA and TCP, as more phospholipids were coated on the surface of these two calcium particles than CaCO₃. Phospholipid coating increased the electrostatic repulsions between particles, preventing the particles from aggregating and precipitating. In addition, the digestibility of phospholipid-coated insoluble calcium particles was tested in simulated gastric juice, and the dissolution time of these insoluble calcium particles was prolonged through phospholipid coating.     

Feasibility of Using Phytoextraction to Remediate a Compost-Based Soil Contaminated with Cadmium

Greenhouse and in-situ field experiments were used to determine the potential for phytoextraction to remediate soil contaminated with Cd from municipal solid waste (MSW) and sewage sludge (SS) compost application at a Peterborough (Canada) site. For the greenhouse experiment, one native (Chenopodium album) and three naturalized (Poa compressa, Brassica juncea, Helianthus annuus) plant species were planted in soil containing no detectable Cd (<1.0 μg·g^?1), and soil from the site containing low (5.0 ± 0.3 μg·g^?1 Cd), and high (16.5 ± 1.2 μg?g^?1 Cd) Cd concentrations. Plant uptake was low (root BAFs ≤0.5) for all species except P. compressa in the low Cd treatment (BAF 1.0). Only B. juncea accumulated Cd in its shoots, though uptake was low (BAF ≤0.3). For the field experiment, B. juncea was planted in-situ in areas of low and high Cd concentrations. Brassica juncea Cd uptake was low (root and shoot BAFs <0.2) in both treatments. Sequential extraction analysis indicated that Cd is retained primarily by low bioavailability soil fractions, and phytoextraction is therefore not feasible at this site. Though low Cd bioavailability has negative implications for Cd phytoextraction from MSW/SS compost-based soils, it may limit receptor exposure to Cd sufficiently to eliminate the potential for risk at this site.     

Voltage Clamp of Cardiac Muscle in a Double Sucrose Gap: A Feasibility Study

A method of stabilizing the membrane potential of a small area of cardiac muscle membrane and the limitations of this method are described. Tiny bundles or strands, approximately 80 μm in diameter, of electrically interconnected fibers from the ventricles of rabbit hearts were used in a double sucrose gap. Current records associated with step changes in voltage were complicated by two capacitive surges of current of nodal and nonnodal origin and large “leakage” currents of nonnodal origin resulting mainly from the multifibered nature of the preparation and emphasized by the method. The transient, inward membrane currents in response to moderate depolarizing steps in command potential had the same duration as the upstroke of the action potential. In good runs, currents were smooth and free from notches. These initial currents behaved qualitatively like the initial sodium currents in squid axon and in other excitable membranes. A fraction of the initial sodium current persisted at least as long as 300 ms. The relationship between peak initial current and voltage was graded and linear in the positive direction. In the negative region the relationship was often very steep, indicating insufficient voltage control of all the membranes despite the squareness of the voltage record. Other indications of inadequacy of control could occur and thus even with this optimum preparation of cardiac muscle it was not feasible to analyze quantitatively either the initial or the prolonged sodium currents.     

Preliminary Experimental Results of Pellet Injection on the HL-2A Tokamak

Plasma Physics Reports - A pellet injector was installed on the HL-2A tokamak, and preliminary experiments were performed recently. In this paper, the impact of pellet injection on the...     

A Pilot Study to Assess the Feasibility of Transcutaneous Glomerular Filtration Rate Measurement Using Fluorescence-Labelled Sinistrin in Dogs and Cats

In dogs and cats an assessment of renal function is often needed, however, existing methods including urine and plasma clearances are invasive, cumbersome and time consuming. This pilot study evaluated the feasibility of a transcutaneous glomerular filtration rate (GFR) measurement in dogs and cats. Additionally the optimal dose and location for the transcutaneous measurement device were investigated. Renal elimination of fluorescein-isothiocyanate-labelled sinistrin (FITC-S) was measured transcutaneously for 4 hours. The procedures were performed in awake, freely moving animals using escalating doses of FITC-S (10 mg/kg, 30 mg/kg, 50 mg/kg) with a wash-out period of at least 24 h in between. Multiple devices were placed on each animal. The resulting FITC-S disappearance curves were visually assessed to determine the most suitable location and the appropriate dose to reach an adequate transcutaneous peak signal for kinetic analysis. In both species 30 mg/kg were adequate for kinetic calculation. The most suitable place for the device was the lateral thoracic wall in dogs and the ventral abdominal wall in cats, respectively. Transcutaneous FITC-S clearance was then repeated using the optimal dose and location and in parallel with an additional plasma sinistrin clearance. Plasma elimination half-lives [min] were 26, 31 and 35, and corresponding transcutaneous elimination half-lives [min] were 26, 34 and 55, respectively in the dogs. Plasma elimination half-lives [min] were 51, 60 and 61, and corresponding transcutaneous elimination half-lives [min] were 75, 96 and 83, respectively in the cats. In conclusion, transcutaneous FITC-S clearance is a feasible method for the assessment of GFR in awake dogs and cats. It is noninvasive, well tolerated and easy to perform even in a clinical setting with results being readily available. A dose of 30 mg/kg of FITC-S seems adequate for kinetic assessment. Further studies are now needed to establish reference values and evaluate transcutaneous renal clearance in various conditions.     

PAT-Based Control of Fluid Bed Coating Process Using NIR Spectroscopy to Monitor the Cellulose Coating on Pharmaceutical Pellets

Current endeavor was aimed towards monitoring percent weight build-up during functional coating process on drug-layered pellets. Near-infrared (NIR) spectroscopy is an emerging process analytical technology (PAT) tool which was employed here within quality by design (QbD) framework. Samples were withdrawn after spraying every 15-Kg cellulosic coating material during Wurster coating process of drug-loaded pellets. NIR spectra of these samples were acquired using cup spinner assembly of Thermoscientific Antaris II, followed by multivariate analysis using partial least squares (PLS) calibration model. PLS model was built by selecting various absorption regions of NIR spectra for Ethyl cellulose, drug and correlating the absorption values with actual percent weight build up determined by HPLC. The spectral regions of 8971.04 to 8250.77 cm^?1, 7515.24 to 7108.33 cm^?1, and 5257.00 to 5098.87 cm^?1 were found to be specific to cellulose, where as the spectral region of 6004.45 to 5844.14 cm^?1was found to be specific to drug. The final model gave superb correlation co-efficient value of 0.9994 for calibration and 0.9984 for validation with low root mean square of error (RMSE) values of 0.147 for calibration and 0.371 for validation using 6 factors. The developed correlation between the NIR spectra and cellulose content is useful in precise at-line prediction of functional coat value and can be used for monitoring the Wurster coating process.