Stabilization of optical characteristics of DNA cholesteric liquid-crystalline dispersions

Abnormal optical properties of liquid-crystalline dispersions (phases) formed as a result of phase exclusion of double-stranded DNA and RNA from water-salt poly(ethylene glycol) solutions and X-ray parameters of these phases are compared. It is shown that the cholesteric packing of nucleic acid molecules is realized at the certain osmotic pressure of a solvent only. A comparison of the optical properties of liquid-crystalline phases (dispersions) to their X-ray parameters allows one to put forward a suggestion on various hydratation (fluctuation) regimes of the nucleic acid behaviour under the condensed phases formation and factors, influencing the mode of packing of these molecules in phases formed. It is shown as well, that immobilization of DNA cholesteric liquid-crystalline particles in the content of polymeric matrix is accompanied by the stabilization of these particles and, hence, their specific abnormal optical activity as well as by formation of particles having a structure, which corresponds to the "optically isotropic ordered liquid" without abnormal optical activity. Data on stabilization of the cholesteric structure of liquid-crystalline DNA dispersions by creation of polymeric chelate bridges between the neighbouring DNA molecules, fixed in the structure of liquid-crystalline dispersions, are shown.     

Augmentation of facial soft-tissue defects with Alloderm dermal graft

The aim of the study was TPS diagnostic value determination in the serum of women with breast cancer as compared with MCA and CA 15-3. The relationship between the serum concentration of these antigens and patient age, clinical stage, histological grade, presence of metastases to lymph nodes and histological type of neoplasm was evaluated. Studies were conducted on the sera of 139 women before surgical procedure aged 28-81, treated in the Clinic of Oncology, at Karol Marcinkowski University of Medical Sciences in Poznań. The TPS concentration was determined using the "BEKI Diagnostics" immunoenzymatic method, MCA - by the "Roche" test and CA 15-3 concentration was determined by the "Abbott" immunofluorescent test. The study showed significantly higher levels of TPS, CA 15-3 and MCA in women with cancer, compared with values in healthy women and women with mastopathy. The highest median of concentration and frequency of occurrence was obtained for TPS. A correlation between enhancement of TPS and CA 15-3 concentration with clinical stage was observed. A similar connection was noted in women with metastases to the lymph nodes. Serum MCA concentration results did not demonstrate the above effects. The study suggests, that in estimating the clinical condition of women with breast cancer, the simultaneous determination of TPS with CA 15-3 seems to be a more useful prognostic factor than TPS or CA 15-3 with MCA.     

Refining the level for anticipated hepatotoxicity in acetaminophen poisoning

Treatment of an acetaminophen overdose with N-acetyl cysteine usually is based on the position of the 4-h acetaminophen (APAP) level on the Rumack-Matthew nomogram; however, there is disagreement on the level at which clinically relevant hepatotoxicity occurs. A retrospective review of all acute adult formulation APAP exposures reported to our poison center between 1986 and 1993 was performed and cases corresponding to the "possible risk or toxicity" range on the nomogram were identified. Our current poison center protocol for APAP poisoning does not recommend treatment with N-acetylcysteine (NAC) in low-risk patients if the 4-h serum APAP level or the extrapolated equivalent falls within the possible toxicity range on the nomogram. Seventeen cases met the inclusion criteria for the study and received no NAC; six additional patients met inclusion criteria but received one or two doses of NAC before therapy was discontinued. No patients in either group demonstrated clinical evidence of hepatotoxicity. This pilot study suggests that patients with no risk factors and APAP levels in the "possible risk" range may not require NAC therapy.     

Experimental and clinical validation of auto- and allodermoplasty using transverse dermal micrografts in deep burns

A new method of autoallodermoplasty is proposed which is as follows: a patient's skin band is cut out 40 times less than the total area of the wound surface. The wound in the donor area is sutured tightly. The skin flap is dissected to thin transverse rectangular pieces with a special microdermatome or with a razor and then they are laid with their lateral side onto the wound and covered with the allo-skin. Experimental and clinical observations have shown that at remote terms both the anatomical and functional restitution of the integument occurred. The method is indicated for huge dermal defects of the "functionally passive" areas in patients with restricted, not big resources of the donor sites, especially in patients with high operative risk.     

Directional organization of eye movement and visual signals in the floccular lobe of the monkey cerebellum

The floccular lobe of the monkey is critical for the generation of visually-guided smooth eye movements. The present experiments reveal physiological correlates of the directional organization in the primate floccular lobe by examining the selectivity for direction of eye motion and visual stimulation in the firing of individual Purkinje cells (PCs) and mossy fibers. During tracking of sinusoidal target motion along different axes in the frontoparallel plane, PCs fell into two classes based on the axis that caused the largest modulation of simple-spike firing rate. For "horizontal" PCs, the response was maximal during horizontal eye movements, with increases in firing rate during pursuit toward the side of recording (ipsiversive). For "vertical" PCs, the response was maximal during eye movement along an axis just off pure vertical, with increases in firing rate during pursuit directed downward and slightly contraversive. During pursuit of target motion at constant velocity, PCs again fell into horizontal and vertical classes that matched the results from sinusoidal tracking. In addition, the directional tuning of the sustained "eye velocity" and transient "visual" components of the neural responses obtained during constant velocity tracking were very similar. PCs displayed very broad tuning approximating a cosine tuning curve; the mean half-maximum bandwidth of their tuning curves was 170-180 degrees. Other cerebellar elements, related purely to eye movement and presumed to be mossy fibers, exhibited tuning approximately 40 degrees narrower than PCs and had best directions that clustered around the four cardinal directions. Our data indicate that the motion signals encoded by PCs in the monkey floccular lobe are segregated into channels that are consistent with a coordinate system defined by the vestibular apparatus and eye muscles. The differences between the tuning properties exhibited by PCs compared with mossy fibers indicate that a spatial transformation occurs within the floccular lobe.     

在磨难中坚持 在历练中成熟——高炼悸千锤酉炼的游戏人生

几周前,我在美国访问了一家州政府。他们将自己全新的企业软件外包给了一家基于美国的国际软件公司,我们姑且称这家公司为Smarty,合同总价达到数百万美金。合同中包括下面这些条款：     

Thermodynamics of iron-aluminum alloys at 1573 K

The activities of iron (Fe) and aluminum (Al) were measured in Fe-Al alloys at 1573 K using the ion-current-ratio technique in a high-temperature Knudsen cell mass spectrometer. The Fe-Al solutions exhibited negative deviations from ideality over the entire composition range. The activity coefficientsγ _Fe, andγ _A1 are given by the following equations as a function of mole fraction (x _Fe,x _Al): 1 $$\begin{gathered} 0< \chi _{A1}< 0.4 \hfill \\ ln \gamma _{Fe} = - 4.511 ( \pm 0.008)\chi _{A1}^2 \hfill \\ ln \gamma _{A1} = - 4.462 ( \pm 0.029)\chi _{Fe}^2 + 0.325( \pm 0.013) \hfill \\ 0.6< \chi _{A1}< 1.0 \hfill \\ ln \gamma _{Fe} = - 4.065 ( \pm 0.006)\chi _{A1}^2 + 0.099( \pm 0.003) \hfill \\ ln \gamma _{A1} = - 4.092 ( \pm 0.026)\chi _{Fe}^2 + 0.002( \pm 0.001) \hfill \\ \end{gathered} $$ The results showed good agreement with those obtained from previous investigations at other temperatures by extrapolation of the activity data to 1573 K.     

Models of human reaction to vehicle environments

Models for predicting human comfort responses to environmental variables are presented for diverse vehicles. Air mode studies reveal that comfort is a function of vertical and transverse accelerations, noise levels and seat factors, as well as manoeuvre conditions. Comfort models for ground-based vehicles involve roll rates and noise levels.     

Role of primate medial vestibular nucleus in long-term adaptive plasticity of vestibuloocular reflex

1. Fifteen hundred and thirty cells were recorded in the medial vestibular nucleus (MVN) of alert monkeys whose vestibuloocular reflex (VOR) had been adapted to one of two kinds of spectacles. The "high-gain" sample was recorded from monkeys that had worn 2.0 x telescopic spectacles; the gain of the VOR in the dark (eye velocity divided by head velocity) was greater than 1.5. The "low-gain" sample was recorded from monkeys that had worn goggles providing a visual field that was fixed with respect to the freely turning head; the gain of the VOR was less than 0.4. 2. Cells showing modulation of firing rate related to imposed head velocity were grouped into four categories: pure vestibular (10), vestibular-plus-saccade (10), vestibular-plus-position (10), and vestibular-plus-head/body (24). Sensitivity to head velocity was measured from averaged responses to sinusoidal, 0.4-Hz whole-body oscillation in the horizontal plane. Almost all cells (98%) having increased firing during ipsilateral head rotation received inputs from the horizontal semicircular canals. Conversely, 82% of cells having increased firing during contralateral head rotation received inputs from the vertical canals. 3. There were no statistically significant differences in resting discharge rate, phase shift, or sensitivity to head velocity between the high- and low-gain samples of any of the cell types. Nonetheless, there was a consistent tendency, evident in all the functionally defined cell groups, for the sensitivity to be about 20% greater in the high-gain samples. However, this difference is small by comparison with the fourfold difference in VOR gain. 4. Detailed scrutiny of the response properties of individual cells suggested that the small differences in sensitivity reflect small changes distributed throughout the population, rather than large and potentially significant changes within a small sub-population. 5. Our data indicate that large, adaptive changes in the gain of the VOR are accompanied by only minor changes in the vestibular sensitivity and no changes in the phase shift or resting discharge rates of cells in the MVN. It remains possible that large changes in vestibular sensitivity occurred in cells we did not sample or in subgroups we could not identify. We argue that this is unlikely and that the major changes underlying VOR plasticity occur after the first central synapse in the VOR pathways.