Acquisition of American sign language by a noncommunicating autistic child

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents. Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1-2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1-2 ppm, the clearance values for hemoperfusion were some 5-7 times higher than those for hemodialysis. In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquats less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.     

Transport, manipulation, and reaction of biological cells on-chip using electrokinetic effects

A microfluidic system was fabricated on a glass chip to study mobilization of biological cells on-chip. Electroosmotic and/or electrophoretic pumping were used to drive the cell transport within a network of capillary channels. Whole cells such as Saccharomyces cerevisiae, canine erythrocyte, and Escherichia coli were employed in this work. Photographs are presented to illustrate how cells are selected and transported from one location to another within the capillary network, with velocities up to about 0.5 mm/s in capillaries with a 15- x 55-microns cross section. The mixing of canine erythrocytes with the lysing agent sodium dodecyl sulfate, at an intersection within the chip, was performed to demonstrate that cell selection and subsequent reaction can be accomplished within the microchip.     

Nanoflow solvent gradient delivery from a microfabricated device for protein identifications by electrospray ionization mass spectrometry

Microfabrication technology offers the opportunity to construct microfluidic modules which are designed to perform specific, dedicated functions. Here we report the construction of a microfabricated device for the generation and delivery by electroosmotic pumping of solvent gradients at nanoliter per minute flow rates. The device consists of three solvent reservoirs and channels which were etched in glass. Solvent gradients and solvent flows were generated by computer controlled differential electroosmotic pumping of aqueous and organic phase, respectively, from the solvent reservoirs. The device was integrated into an analytical system consisting of the solvent gradient delivery module, a reverse phase microcolumn and an electrospray ionization ion trap mass spectrometer (MS). The system was used for the analysis at high sensitivity of peptides and peptide mixtures generated by proteolytic digestion of proteins. We have measured an absolute limit of detection as low as 1 fmol and a concentration limit of detection at the 100 amol/microL level. The system was also successfully used for the identification of proteins separated by 1D and 2D gel electrophoresis. This was achieved by gradient frontal analysis of the peptide mixture generated by proteolysis of the respective proteins, and the automated generation and interpretation of collision-induced dissociation spectra.     

Capillary isotachophoresis with fiber-optic Raman spectroscopic detection. Performance and application to ribonucleotides

A fiber-optic Raman probe fitted with a microscope objective was used to obtain on-line normal Raman spectra of adenosine 5'-monophosphate, cytidine 5'-monophosphate, guanosine 5'-monophosphate and uridine 5'-monophosphate separated by capillary isotachophoresis. With multimode optical fiber, the system interrograted a 40-micron length of capillary. Fiber-optic coupling facilitated use of an unmodified spectrograph and conventional capillary mounting systems. Raman spectra were excited with a 2W 532 nm NdYVO4, laser as the excitation source, with collection of 1 spectrum per second. Even at 2.10(-5) M initial concentration, Raman spectra were obtained at a good signal-to-noise ratio.     

Temperature dependence of the Qy resonance Raman spectra of bacteriochlorophylls, the primary electron donor, and bacteriopheophytins in the bacterial photosynthetic reaction center

Qy-excited resonance Raman spectra of the accessory bacteriochlorophylls (B), the bacteriopheophytins (H), and the primary electron donor (P) in the bacterial photosynthetic reaction center (RC) of Rhodobacter sphaeroides have been obtained at 95 and 278 K. Frequency and intensity differences are observed in the low-frequency region of the P vibrational spectrum when the sample is cooled from 278 to 95 K. The B and H spectra exhibit minimal changes of frequencies and relative intensities as a function of temperature. The mode patterns in the Raman spectra of B and H differ very little from Raman spectra of the chromophores in vitro. The Raman scattering cross sections of B and H are 6-7 times larger than those for analogous modes of P at 278 K. The cross sections of B and of H are 3-4 times larger at 95 K than at 278 K, while the cross sections of P are approximately constant with temperature. The temperature dependence of the Raman cross sections for B and H suggests that pure dephasing arising from coupling to low-frequency solvent/protein modes is important in the damping of their excited states. The weak Raman cross sections of the special pair suggest that the excited state of P is damped by very rapid (<30 fs) electronic relaxation processes. These resonance Raman spectra provide information for developing multimode vibronic models of the excited-state structure and dynamics of the chromophores in the RC.     

Chemiluminescence detection in integrated post-separation reactors for microchip-based capillary electrophoresis and affinity electrophoresis

Chemiluminescence (CL) detection based on the horseradish peroxidase (HRP) catalyzed reaction of luminol with peroxide was investigated as a post-separation detection scheme for microchip-based capillary electrophoresis. An integrated injector, separator and post-separation reactor was fabricated on planar glass wafers. The fluorescein conjugate of HRP (HRP-F1) was used as a sample for optimization of the CL detector response. In devices etched 10 microm deep, with an aluminum mirror integrated onto the backside of the detection zone to enhance collection efficiency, the detection limit, estimated at 3 standard deviations (SD) above background noise, for 1 nL injected sample plugs was 35 nM in HRP-F1. In devices etched 40 microm deep, 8 nL plugs gave a detection limit of 7 nM. Separation and CL detection of the products of an immunological reaction of a F(ab')2 fragment of the HRP conjugate of goat anti-mouse immunoglobulin G (IgG) with mouse IgG was performed on-chip. A linear calibration curve was obtained for the decrease in peak height of the HRP conjugate (53 microg/mL) with increasing mouse IgG (0-60 microg/mL). When microperoxidase was used as an internal standard, the R2 value of a linear least-squares fit was 0.9867, and the relative errors in the slope and intercept were +/- 5.8 and +/- 1.3 %, respectively.     

Determination of leucogentian violet in chicken fat by liquid chromatography with electrochemical and ultraviolet detection: interlaboratory study

A laboratory trial was completed for a liquid chromatographic method that can quantitate leucogentian violet (LGV) in chicken fat at 10 ppb. With this method, LGV is isolated from the fat matrix by a series of liquid-liquid extractions. This trial evaluated 2 detection systems: electrochemical (EC) and ultraviolet (UV). The participating laboratories determined incurred residues at 2 levels as well as fat samples fortified at 5, 10, and 20 ppb. Using UV detection, the 3 laboratories reported the following range of recoveries: 71.0-89.6% at 5 ppb, 74.7-83.9% at 10 ppb, and 77.2-79.0% at 20 ppb. When these same samples were chromatographed with EC detection, the 2 reporting laboratories obtained the following average recoveries: 79.0 and 92.5% at 5 ppb, 75.9 and 85.4% at 10 ppb, and 77.3 and 79.8% at 20 ppb. The average concentrations found for the first level of incurred sample were 6.3, 6.3, and 5.4 ppb with coefficients of variation (CVs) of 2.4, 7.6, and 33.7%, respectively, when UV detection was used. Samples chromatographed with EC detection averaged 6.3 and 6.4 ppb with CVs of 4.0 and 8.2%, respectively. The second level of incurred sample gave average concentrations of 27.6, 29.0, and 10.9 ppb with CVs of 11.0, 5.0, and 42.8%, respectively, when the UV detection system was used. With the EC detector, the concentrations averaged 27.2 and 30.7 ppb with CVs of 15.7 and 3.5%, respectively.     

Influence of conserved amino acids on the structure and environment of the heme of cytochrome c2. A resonance Raman study

Resonance Raman spectra using Soret excitations of oxidized and reduced Rhodobacter capsulatus cytochrome c2 at pH 7.5 were studied. The spectra of oxidized cytochrome c2 show three components for the v10 mode at 1638, 1633, and 1629 cm(-1). The intensities of these components are sensitive to the excitation wavelength. This effect is explained in the context of a conformational equilibrium of the ferriheme between a nearly planar structure and two ruffled structures. In the case of reduced cytochrome c2, the absolute frequencies as well as the excitation-dependent frequency dispersion of the v10 mode (1618-1621 cm(-1)) indicate a displacement of the conformational equilibrium of heme toward the more planar structures. To measure the influence of some key amino acid residues on the heme-protein interaction of cytochrome c2, four site-directed mutants of Rb. capsulatus cytochrome c2 have been studied by resonance Raman spectroscopy and their spectra compared with the spectra obtained for the wild type cytochrome. The mutants studied are K14E/K32E, P35A, W67Y, and Y75F. The spectral changes induced by the mutations are interpreted in terms of alterations in the structure and/or environment of the cytochrome c2 heme in the framework of the expected role of the different amino acid residues in the stability and redox potential.     

Highly Er3+/Yb3+ Co-Doped Fluoroaluminate Glasses for Microchip Laser at 1.54 μm

A series of highly Er3 /Yb3 co-doped fluoroaluminate glasses were investigated in order to develop a microchip laser at 1.54 μm under 980 nm excitation. Measurements of absorption, emission and up-conversion spectra were performed to examine the effect of concentration quenching on spectroscopic properties. In the glasses with Er3 concentrations below 10% (mol fraction), concentration quenching is low and the Er3 /Yb3 co-doped fluoroaluminate glasses gave stronger fluorescence of 1.54 μm from the 4I13/2→ 4I15/2 transition than those of Er3 singly-doped glasses. In the glass with Er3 concentrations above 10%, concentration quenching of 1.54 μm obviously occurs more than that of the Er3 singly-doped samples because of the back energy-transfer from Er3 to Yb3 . To obtain the highest emission efficiency at 1.54 μm, the optimum in mol fraction when the Er3 concentration is less than 10%.     

保温时间对锰氧化物刻蚀金刚石单晶的影响

研究了在不同保温时间下MnO₂对金刚石单晶的表面刻蚀, 通过扫描电子显微镜和拉曼光谱对刻蚀后金刚石单晶不同晶面的表面形貌和刻蚀机理的进行了表征与分析, 并对腐蚀过程中金刚石表现出来的各向异性进行了探讨。结果表明: 当金刚石和MnO₂质量比为1:5时, 金刚石单晶的刻蚀程度随着保温时间的延长而增大; 在相同保温时间下, {111}晶面比{100}晶面刻蚀严重; 金刚石表面腐蚀后的形貌与对应晶面的碳原子排列有关, {100}面倾向于形成四边形的刻蚀坑, 而{111}面则会形成轮廓为三角形的腐蚀坑, 且金刚石单颗粒的抗压强度随刻蚀时间的延长而下降; 刻蚀机理为MnO₂与金刚石表面C原子发生反应, 导致金刚石表面发生刻蚀。     

单相Sm掺杂BaTiO3陶瓷的结构研究

采用高温固相反应法,在1 400℃/12h烧结条件下制备了具有Ti空位补偿的Ba1-xSmxTi1-x/4O3(BST;x=0.02~0.07)陶瓷。利用XRD对BST陶瓷的晶体结构进行表征,并在532和638nm两种激发波长下对其进行拉曼光谱测试。结果表明:当x≤0.07时,所有的BST陶瓷均表现为单相钙钛矿结构,并且随着Sm含量的增加,其晶体结构由四方相(x≤0.06)转变为立方相(x=0.07);不同激发波长下的拉曼测试证实高频谱来自稀土Sm^3+的荧光效应。     

High Quantum Efficiency and High Concentration Erbium-Doped Silica Glasses Fabricated by Sintering Nanoporous Glasses

With the development of technology and the de-mand of modern optical communication ,the attempt isto produce miniature ,integrated solid lasers ,and in-tegrated active devices .These works promote the evo-lution of the erbium-doped integrated waveguide am-plifier and the microchip laser application[1 ,2]. Toachieve sufficient gain in short active length, rareearth ions doped in waveguide amplifiers and hostglasses must be high enough. However , rare earthions tend toformclusters in silica glas…     

Metabolic alterations in hepatocytes promoted by the herbicides paraquat, dinoseb and 2,4-D

The cytotoxic effects of the herbicides paraquat (1,1'-dimethyl-4,4'-bipyridylium dichloride), dinoseb (2-sec-butyl-4,6-dinitrophenol) and 2,4-D (2,4-dichlorophenoxyacetic acid) on freshly isolated rat hepatocytes were investigated. Paraquat and 2,4-D (1-10 mM) caused a dose and time dependent cell death accompanied by depletion of intracellular glutathione (GSH) and mirroring increase of oxidized glutathione (GSSG). Dinoseb, the most effective cytotoxic compound under study (used in concentrations 1000 fold lower than paraquat and 2,4-D), exhibited moderate effects upon the level of GSH and GSSG. These limited effects are at variance with significant effects upon the adenine and pyridine nucleotide contents. ATP and NADH levels are rapidly depleted by herbicide metabolism. This depletion is observed in the millimolar range for paraquat and 2,4-D and in the micromolar range for dinoseb. 2,4-D completely depletes cellular ATP, with subsequent cell death, as detected by LDH leakage. Paraquat rapidly depletes NADH, according to the redox cycling of the herbicide metabolism. The most effective compound is dinoseb since it exerts similar effects as described for paraquat and 2,4-D at concentrations 1000 fold lower. Simultaneously with NADH and ATP depletion, the levels of ADP, AMP and NAD+ increase in hepatocytes incubated in the presence of the herbicides. In contrast to NADH, the time course and extent of ATP depletion and fall in energy charge correlate reasonably with the time of onset and rate of cell death. It is concluded that the herbicides, paraquat and 2,4-D are hepatotoxic and initiate the process of cell death by decreasing cellular GSH.(ABSTRACT TRUNCATED AT 250 WORDS)     

Haemoperfusion treatment in pigs experimentally intoxicated by paraquat

1. Because of their similarity in renal morphology and physiology to humans, domestic pigs (gilts, 70 kg) were bolus treated by intramuscular injection of 74, 17, and 6 mg kg-1 and by oral loading (70 mg kg-1 n = 4) of paraquat. The concentration peak of plasma paraquat was reached at 1.5 - 2.5 h. Renal clearance of paraquat rose to its maximum at 5-6 h after intoxication and then sharply decreased indicating renal failure. All the intoxicated pigs died. 2. An additional 10 gilts were also orally treated with 70 mg kg-1 paraquat but received haemoperfusion from 2 h post intoxication for either 2 h (n = 6) or 6 h (n = 4). The 2 h haemoperfusion resulted in a 5.1% toxin removal but failed to save any of six poisoned pigs. Prolonged 6 h haemoperfusion successfully rescued three out of four intoxicated pigs. 3. The plasma paraquat concentrations of the three surviving pigs were above 2 mg l-1 at 10 h post intoxication. This level is not only similar to those of untreated animals that died later, but also well beyond the suggested limit for survival of poisoned patients. 4. Pigs proved to be a good animal model for studies in paraquat poisoning and/or haemoperfusion. It is also suggested that early haemoperfusion is effective in treating paraquat poisoning even in very severe cases due to its possible detoxicating effect in addition to toxin removal.     

3.1 μm mid-infrared luminescence in Er3+ doped ZnF2 modified aluminum fluoride glass

Herein, melt-quenching and Er³⁺ doping were used to synthesize fluoride glass specimens with low phonon energies (582 cm⁻¹). These glass specimens exhibit intense 3.1 μm mid-infrared band emission when they are excited by a 980 nm laser diode, achieving a full width at half maximum (FWHM) of about 166 nm. This 3.1 μm emission intensity is enhanced by the introduction of ZnF₂ to the AlF₃-based fluoride glass. Up-conversion emission, strong near-infrared emission, and fluorescence lifetime are enhanced to different degrees by increasing the ZnF₂ content. Moreover, the spectroscopic characteristics of the glass specimens and the highly efficient Er³⁺: ⁴S_3/2 → ⁴F_9/2 transition's energy transfer mechanism were investigated. The absorption spectra and emission spectra of these aluminum fluoride glass specimens were used to calculate their gain coefficients and maximum cross sections at 1.5 and 3.1 μm. Overall, the spectral properties of these prepared aluminum fluoride glass specimens demonstrate their high potential for use as infrared laser host materials.     

Superoxide-mediated cytotoxicity in superoxide dismutase-deficient fetal fibroblasts

To investigate the roles of CuZn superoxide dismutase (CuZnSOD) and Mn superoxide dismutase (MnSOD) in oxygen radical-mediated cytotoxicity and to distinguish the actions of these two enzymes, fetal fibroblasts were derived from mouse fetuses that are either deficient in CuZnSOD (Sod1-/+ and -/-) or MnSOD (Sod2-1+ and -/-) for in vitro studies. Whereas the phenotype of the Sod1 mutant animals did not differ from that of their normal littermates, the growth of Sod1-/- fetal fibroblasts was only 25% of that of the -/+ and +/+ cells. On the other hand, although almost all homozygous Sod2 mutant animals (-/-) died within 10 days after birth, cultivation of Sod2-/- fetal fibroblasts was possible and their growth was about 60% that of -/+ and +/+ cells. When cultured cells were subjected to treatment with paraquat to assess their ability to grow in the presence of high levels of superoxide radicals, Sod1-/- cells were 80 times more sensitive and Sod2-/- cells were 12 times more sensitive to paraquat than wild-type cells. In addition, whereas the loss of 50% CuZnSOD rendered Sod1-/+ cells almost twice more sensitive to paraquat than +/+ cells, loss of 50% MnSOD had no effect on paraquat sensitivity. Our results suggest that CuZnSOD-deficient cells are more sensitive to oxygen toxicity than are MnSOD-deficient cells, that paraquat causes free radical-induced damage in both the mitochondria and cytoplasm, and that SOD compartmentalized in the cytosol cannot compensate for the loss of SOD in the mitochondria and vice versa.     

The deleterious effects of fungicides and herbicides on Xenopus laevis embryos

Groups of 30 Xenopus laevis embryos, at "tail-bud" stage (Nieukoop-Faber stages 22-24) were exposed to 0.1-2 ppm concentrations of various pesticides for 1 to 10 days. The pesticides used were chloranil and dichlone (both are fungicidal and herbicidal); diquat (herbicide); and nabam (fungicide). The parameters examined were mortality, gross morphology, histology, and behavior. Chloranil (1.25 to 1.75 ppm) treated embryos showed abnormalities of the otolith, optic cup, and general pigmentation. Their movement was sporadically convulsive and they were unable to maintain proper balance. Dichlone (0.1 to 0.15 ppm) disrupted the development of the cephalic end of the embryo. Many of these embryos developed a slightly retarded trunk and tail only. These headless embryos lived for a time and were relatively lethargic. Diquat (0.75 to 2.0 ppm) administration reduced body size and pigmentation, and altered body shape. When embryos were treated with both 1.0 ppm of diquat and 2.0 ppm of nabam the integrity of myomeres and myocommata of the musculature was disrupted. The histological bases of these morphological and behavioral changes are discussed.     

Luminescence of Er3+ Doped Titanium Barium Glass Microsphere under 514 nm Excitation

The titanium barium glass microspheres doped with Er2O3 were designed and prepared. The components of the glass sample were 25TiO2-27BaCO3-8Ba(NO3)2-5ZnO2-10CaCO3-5H3BO3-10SiO2-7water glass-3Er2O3 (%, mass fraction). The emission spectra of titanium barium glass matrix and the titanium barium glass microsphere under 514 nm excitation were measured with micro-Raman spectrometer. Whispering gallery modes in the emission spectra from a 31 μm glass microsphere were observed. Many regularly spaced, sharp peaks appeared in the emission spectra of the Er2O3-doped glass microsphere. The wavelength separation between the two adjacent peaks is 1.92 nm for the 31 μm microsphere. According to the Lorenz-Mie formula, the calculated value of the wavelength separation between the two adjacent peaks is 1.95 nm. The observed resonances could be assigned by using the well-known Lorenz-Mie formula.     

A physiologically based approach to the study of bisphenol A and other estrogenic chemicals on the size of reproductive organs, daily sperm production, and behavior

Two chemicals previously shown to have estrogenic activity, bisphenol A and octylphenol, were examined for their effects on accessory reproductive organs and daily sperm production in male offspring of mice fed these chemicals during pregnancy. These chemicals are used in the manufacture of plastics and other products, and have been detected in food and water consumed by animals and people. From gestation day 11-17 female mice were fed an average concentration (dissolved in oil) of bisphenol A or octylphenol of 2 ng/g body weight (2 ppb) and 20 ng/g (20 ppb). The 2 ppb dose of bisphenol A is lower than the amount reported to be swallowed during the first hour after application of a plastic dental sealant (up to 931 micrograms; 13.3 ppb in a 70 kg adult). We found that the 2 ng/g dose of bisphenol A permanently increased the size of the preputial glands, but reduced the size of the epididymides; these organs develop from different embryonic tissues. At 20 ng/g, bisphenol A significantly decreased efficiency of sperm production (daily sperm production per g testis) by 20% relative to control males. The only significant effect of octylphenol was a reduction in daily sperm production and efficiency of sperm production at the 2 ng/g dose. A new approach to studying physiologically relevant doses of environmental endocrine disruptors is discussed, particularly with regard to the development of the reproductive organs, the brain, and behavior.