电源造成的黑屏问题

某周日,朋友小元让我速去网吧抢修机子。赶到现场,我首先询问状况,小元告诉我这台机子有时能点亮,但要想进入系统只能按F1键。进入后,进行任何操作都正常,但重启或再次开机后就会出现黑屏现象,且没有规律。我说:“启动后,电脑有提示语句给出吗?”。他却说:“可能有……吧”。这     

iPod在手,遥控无忧!

前言原先在家看电视的时候,总和爸爸妈妈争抢遥控器,现在可好了,我有iPod的了,利用其自身超强的功能,将其改造成红外遥控器就可以控制电视了!呵呵,这下父母把电视遥控器藏起来也难不住我了!当然,只要把iPod改装成可以接收红外信号的设备,还可以控制DVD播放机、空调等家用设备,我们马上开始改造过程吧!一、工具准备一台iPod,任何型号都均可,一台电脑及相应的录音软件,PC需要使用S o u n d F o r g e,M a c需要使用WireTap;Griffin公司的遥控软件;一台PocketPC掌上电脑,操作系统是PocketPC2002或是2003;TotalRemote和同软件一起发售…     

Color from shape from color: a simple formalism with known light sources

Photometric stereo is a well-known technique for recovering surface normals of a surface but requires three or more images of a surface taken under illumination from different directions. At best, one may dispense with the need for multiple images by using colored lights tuned to camera filters. But a less restrictive paradigm is available that uses the orientation-from-color approach, wherein multiple broadband illuminants impinge on a surface simultaneously. In that method, colors for a Lambertian surface lie on an ellipsoid in color space. The method has been applied mainly to single-color objects, with ellipsoid quadratic-form parameters determined from a large number of pixels. However, recently Petrov and Antonova [Color Res. Appl. 21, 97 (1996)] developed an entirely local approach, useful also for multicolored objects with color uniform in each patch. We investigate to what extent a method such as that of Petrov and Antonova can be applied in the ostensibly simpler situation in which the complex lighting environment is known, i.e., a color photometric stereo situation, with all lights in play at once with only a single image to analyze. We find that, assuming a simple model of color formation, we are able to recover the object colors along with surface normals, using only a single image. Because we immerse the object in a known lighting environment, we show that only half of the equations utilized by Petrov and Antonova are actually needed, making the method more stable. Nevertheless, solutions do not exist at every pixel; instead we may determine a best estimate of patch color, using a robust estimator, and then apply that estimate throughout a patch. Results are shown to be quite good compared with ground truth. The simple color model can often be made to hold more exactly by transforming the color space into one corresponding to spectrally sharpened sensors, which are a matrix transform away from the actual camera sensors. In our study the reliability and accuracy of the normal vector and of the surface color recovery algorithm are improved by this straightforward transformation.     

Proliferation/differentiation of osteoblastic human alveolar bone cell cultures in the presence of stainless steel corrosion products

Human osteoblastic alveolar bone cells were cultured for 28 days in control conditions and in the presence of three non-lethal concentrations of AISI 316L stainless steel (SS) corrosion products. Cells were exposed to SS corrosion products in two experimental situations: (i) in selected stages of the incubation time (during the first, second, third and fourth week of culture); and (ii) during the 28 days incubation period. Cultures were characterized for cell proliferation, total protein content, alkaline phosphatase activity (ALP) and ability to form mineralized deposits; culture media was analyzed for ionized calcium (Ca) and phosphorus (P) concentrations throughout the incubation period. The presence of SS corrosion products during the different stages of the incubation period did not significantly affect the cell proliferation; however, a significant dose-dependent deleterious effect was observed on the levels and pattern of ALP activity, concentration of ionized Ca and P in the culture medium and, also, ability to form mineralized deposits, especially in cultures exposed during the first and second week of culture (respectively, lag phase and exponential cell growth phase). Similar effects were observed in cultures exposed to the SS corrosion products during the 28 days incubation period. However, the presence of such products during the third week (when the mineralization process occurs) and, also, during the fourth week, resulted in little or no significant effects on the behavior of alveolar bone cells. Results suggested that SS corrosion products above certain non-lethal concentrations may disturb the proliferation/differentiation relationship of osteoblastic human alveolar bone cell cultures. ©©2000 Kluwer Academic Publishers     

A method for determination of particle magnetic susceptibility with analytical magnetapheresis

We recently developed a new method for simple determination of particle magnetic susceptibility using analytical magnetapheresis. This new method does not require laborious calibration plots and trial susceptibility values as do previous analytical magnetapheresis methods. The new method is based on balancing channel flow rates and magnetically induced flow rates for particle deposition in analytical magnetapheresis. The maximal flow rate for complete particle deposition was determined experimentally and set to equal the magnetically induced flow rate for determining particle magnetic susceptibility. This magnetic susceptibility determination generally takes less than 20 min. Several magnetically susceptible and ion-labeled particles were tested using this new method. The carrier magnetic susceptibilities were varied, and erbium ion-labeled particles were studied experimentally, resulting in successful susceptibility determinations of erbium ion-labeled particles and yeasts. The precision of each measurement was generally approximately 10%. Experimental determination of particle magnetic susceptibilities differed by less than 10% from reference measurements taken using a superconducting quantum interference device magnetometer. This method can determine minimal susceptibilities on the order of 10(-9) cgs. The minimum number of erbium labeling ions per particle required for complete deposition of silicas and yeasts was found to be 6.7 x 10(9). Analytical magnetapheresis shows good potential for use in simple determination of particle magnetic susceptibilities and should become a useful technique.     

Effects of sediment geochemical properties on the toxicity of copper-spiked sediments to the marine amphipod Gammarus locusta

The contribution of some sediment features, namely acid-volatile sulfide (AVS) and total organic carbon (TOC) in order to explain the toxicity of copper-spiked sediments was investigated. A 10-day assay with the marine amphipod Gammarus locusta was performed with three selected sediment types that consisted of different proportions of fine fractions (FF) and TOC (0.5% FF/1% TOC; 25% FF/2% TOC; and 75% FF/4% TOC). Copper toxic effects were observed for 0.5% FF/25% FF sediments when simultaneously extracted copper (SEM(Cu)) minus acid volatile sulfide (SEM(Cu) - AVS) were 0.3 and 3.4 micromol/g, respectively. However, no significant mortality was observed for 75% FF sediment even when the sulfide binding capacity was exceeded (1.1 micromol/g < or = SEM(Cu) - AVS < or = 8.9 micromol/g). These results indicate that mortality could not be described solely as a function of the SEM(Cu) - AVS, suggesting the presence of other binding phases in addition to AVS. Results of the normalized LC50 values to total organic carbon indicated that this component probably also interferes in the amphipod survival, although not completely. The estimated LC50 values were close (2 mg Cu/g C and 8 mg Cu/g C, respectively for 0% FF and 25% FF sediment) although there was still a fourfold difference between them. Considering that none of these sediment features by itself could fully explain copper toxicity, an attempt was made to describe G. locusta mortality as a function of simultaneous SEM(Cu) - AVS and copper concentrations normalized to TOC. Nevertheless, the limited set of data available from this study prevented an attempt to model toxicity as a function of both of these factors. These findings reinforce the need to develop integrated models that include more than one binding phase, sulfide and organic carbon, and also other compartments of the system (e.g. interstitial water) to improve current methodologies for predicting copper toxicity based on sediment geochemical features.     

Automatic 3-D segmentation of internal structures of the head in MR images using a combination of similarity and free-form transformations: Part II, validation on severely atrophied brains

Studies aimed at quantifying neuroanatomical differences between populations require the volume measurements of individual brain structures. If the study contains a large number of images, manual segmentation is not practical. This study tests the hypothesis that a fully automatic, atlas-based segmentation method can be used to quantify atrophy indexes derived from the brain and cerebellum volumes in normal subjects and chronic alcoholics. This is accomplished by registering an atlas volume with a subject volume, first using a global transformation, and then improving the registration using a local transformation. Segmented structures in the atlas volume are then mapped to the corresponding structures in the subject volume using the combined global and local transformations. This technique has been applied to seven normal and seven alcoholic subjects. Three magnetic resonance volumes were obtained for each subject and each volume was segmented automatically, using the atlas-based method. Accuracy was assessed by manually segmenting regions and measuring the similarity between corresponding regions obtained automatically. Repeatability was determined by comparing volume measurements of segmented structures from each acquisition of the same subject. Results demonstrate that the method is accurate, that the results are repeatable, and that it can provide a method for automatic quantification of brain atrophy, even when the degree of atrophy is large.     

Spread of marker bacteria from the hides of cattle in a simulated livestock market and at an abattoir

The spread of microbial contamination on the hides of beef was investigated at two stages in the meat chain: (i) in a simulated livestock market ("the market") using 33 animals, and (ii) in the unloading-to-skinning area of a commercial abattoir using 18 animals. At both stages, harmless bacterial markers (nalidixic acid-resistant Escherichia coli K-12; rifampicin- and nalidixic acid-resistant Pseudomonas fluorescens; and a tetracycline-resistant E. coli) were inoculated on the hides of a small number of selected animals, and their transfer to other animals and the environment was examined. At the market, the initial prevalence of animals positive for the hide markers (9.1% in each phase) introduced in the presale pen, sale ring, and postsale pen changed to 39.4, 15.1, and 54.5%, respectively, by the end of the market process. In addition, widespread contamination of the market environment with the hide markers was observed. At the abattoir, the initial prevalence of animals positive for the hide marker (11.1%) inoculated at unloading increased to 100% (hide before skinning) and 88.8% (skinned carcass). In addition, another marker inoculated on environmental surfaces in lairage pens, races, and stunning box was detected on 83.3% (hide before skinning) and 88.8% (skinned carcass). These results, although obtained with a relatively small number of animals, demonstrate that both the livestock market process and the unloading-to-skinning process at abattoirs can facilitate the extensive spread of microbial contamination on hides not just within, but also between, batches of animals.     

Effect of surfactant gels on dough rheological characteristics and quality of bread

Sodium stearoyl-2-lactylate (SSL), diacetyl tartaric acid esters of monoglyceride (DATEM), glycerol monostearate (GMS), and distilled glycerol monostearate (DGMS) surfactant gels were made with water and varying shortening contents. The effect of these gels on dough rheological characteristics and quality of bread was investigated. Overall, the surfactant gels improved the farinograph and extensograph characteristics of wheat flour, but the improvement reduced to some extent with the presence of shortening in the gels. Alveograph data indicated that dough properties improved with the addition of surfactant gels. Shortening in gels showed varying influence on the dough alveograph properties of wheat flour. The results indicated that the surfactant gels changed the rapid visco analyzer characteristics of wheat flour, and the presence of shortening in gels further altered the characteristics. All surfactant gels improved the volume, specific volume, texture, and overall quality scores of bread, but the improvement varied for different surfactants. By increasing the addition of shortening in gels, though the quality characteristics further improved, the response to surfactants reduced by increasing shortening content.     

Dendrimer-immobilized culture surface as a tool to evaluate formation of cellular cytoskeleton of anchorage-dependent cells

Anchorage-dependent cultivation of human epithelial and keratinocyte cells was carried out on surfaces modified with synthesized dendrimers. Notable elongation of the epithelial cells was recognized on the culture surface immobilized with a dendrimer having D-glucose as a functional ligand, but not when a dendrimer having L-glucose was used or when the dendrimer was ligand-free. This morphological change was attributable to a temporary grasping of the cells at the D-glucose moiety via a glucose transporter-mediated mechanism present in the cell membrane. Following visualization of the actin filaments of the cells, it was considered that the cellular elongation on the D-glucose-bound dendrimer surface reflected the degree of formation of the cellular cytoskeleton. The cellular roundness was calculated by means of image analysis of the individual cells and employed as a parameter to evaluate the formation of the cellular cytoskeleton. In the culture of keratinocytes on the D-glucose-bound dendrimer surface, it was demonstrated that the decrease in the ratio of elongated cells (i.e., cells with a low roundness value) was correlated with the deterioration in the growth potential associated with cellular senescence.