The binding of 3,6-disubstituted bile salts to human serum albumin induces conformational change on the molecule of this protein

The binding of 3,6-hydroxy and keto disubstituted bile salts to human serum albumin was studied using differential scanning calorimetry, fluorescence spectroscopy and circular dichroism. The bile salts assayed did not produce any modification in the shape of the albumin thermogram, its thermal unfolding process in their presence being reversible; however, an increase in the enthalpy of unfolding and in the Tm was observed in the presence of 3,6-diketo and 3-hydroxy-6-keto bile salts. These two derivatives induced a negative circular dichroism spectrum of the protein around 280-290 nm, quenched the native fluorescence of the buried tryptophan of albumin and induced energy transfer between 1 aniline-8-naphthalene sulfonate and the buried tryptophan 214 of albumin. The presence of a keto group at C6 in the steroid ring of the bile salts plays an important role in producing slight movement of the albumin domains, increasing the distance between domains I and II.     

Structural changes during annealing of deformed Pd-25 at % Ni Alloy

X-ray diffraction analysis and residual resistivity measurements are used to study the short-range order and fine crystal structure of the Pd-25 at % Ni solid solution deformed at room temperature and their changes during isochronous annealings. A short-range order was shown to exist in the deformed alloy; the structure of the order does not correspond to the L1₂ superstructure. During the annealing, the character of the order remains unchanged. Possible physical processes that cause the nonmonotonic changes in the short-range order, fine crystal structure parameters, and residual resistivity are considered.     

Unresponsiveness to cannabinoids and reduced addictive effects of opiates in CB1 receptor knockout mice

The function of the central cannabinoid receptor (CB1) was investigated by invalidating its gene. Mutant mice did not respond to cannabinoid drugs, demonstrating the exclusive role of the CB1 receptor in mediating analgesia, reinforcement, hypothermia, hypolocomotion, and hypotension. The acute effects of opiates were unaffected, but the reinforcing properties of morphine and the severity of the withdrawal syndrome were strongly reduced. These observations suggest that the CB1 receptor is involved in the motivational properties of opiates and in the development of physical dependence and extend the concept of an interconnected role of CB1 and opiate receptors in the brain areas mediating addictive behavior.     

电磁干扰滤波器综述

选择这些器件需要确定干扰的类型和来源,及其适用的标准 现在生产的所有电子设备都包含电磁干扰滤波电路.同样,所有开关型电源都有内部的电磁干扰滤波器.但是,在有些环境中,这些电子器件的电磁干扰滤波器需要辅助滤波器,以便满足更加苛刻的电噪声管制或者保护器件免受过多的外部噪声源干扰.     

High-shrinkage-potential porous glass-ceramic supports for high-temperature oxide ceramic membranes

We have optimized the composition of porous glass-ceramic supports compatible with conducting ceramics and have developed a procedure for the fabrication of such supports. High-shrinkage-potential porous supports in the form of dead-end tubes have been shown to be best suited for designing multilayered selective ceramic membranes. We have assessed the effects of various modifiers on the shrinkage curve of such supports. The factors that play a central role in determining the properties of supports have been identified: the amount of burnout additives determines the macroporosity, the addition of low-melting clay influences the shrinkage potential, leaching influences the microporosity, impregnation with a lanthanum salt determines the shape of the shrinkage curve and reactivity, and modification with Al₂O₃ sol determines the heat resistance of the supports.     

Surgical management of meningiomas originating in Meckel's cave

OBJECTIVE: To define the difference of meningiomas that originate in the area of Meckel's cave (MC) (primary MC meningiomas) in regard to the different surgical approaches and postoperative results. METHODS: A retrospective analysis of all meningiomas involving the cranial base displayed 21 cases of meningiomas originating in MC (primary MC meningiomas). These cases were classified according to the tumor extension in four different types: Type I, tumors mainly confined to MC; Type II, MC meningiomas with extension into the middle fossa; Type III, MC meningiomas with extension into the posterior fossa; and Type IV, MC meningiomas with extension into both middle and posterior fossae. RESULTS: Trigeminal neuralgia resolved in all cases in this series, despite tumor type. Trigeminal hypesthesia showed postoperative improvement only in Type III MC meningiomas. In Types I and III, total removal without further morbidity was frequently achieved. Cavernous sinus infiltration, especially in Types II and IV, limited (in some cases) the extent of tumor extirpation. CONCLUSION: Types I, II, and III MC meningiomas have a good prognosis. In most cases, very good outcomes are achieved. Radical tumor removal can usually be achieved without further morbidity and with postoperative improvement of the preexisting symptoms, especially in Types I and III MC meningiomas. On the contrary, Type IV MC meningiomas are usually only subtotally resected. Surgery in such cases may carry a high risk of additional morbidity, especially with regard to the IIIrd, IVth, and VIth cranial nerves. The postoperative outcome regarding facial pain in cases of all tumor types is usually very good. Trigeminal hypesthesia may persist after tumor removal in the majority of cases.     

Segments on bit-mapped graphics displays

The problems associated with using picture segments in interactive applications on workstations with bit-mapped displays are discussed. A method for displaying and updating segments is introduced.