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1.
The gel-to-glass transition in SiO2 xerogels prepared by inorganic sol-gel synthesis was studied. The evolution of the molecular structure is traced using the infrared and lowfrequency Raman spectroscopy methods. The elastic moduli of the samples as well as the pore wall moduli at various stages of heat treatment are determined from the data on Brillouin scattering. The formation of monolithic glass on the macroscopic level manifests itself within a narrow temperature range by the dramatic increase of Young's modulus to the accepted value for fused silica. This phenomenon coincides with structural transformations on the molecular scale: (i) the definite correlation radius (the long-range order sphere) appears; (ii) local distortions of the silica network relax. The presence of structural defects influences the kinetics of vitreous SiO2 formation during xerogel heat treatment.  相似文献   
2.
This paper presents a framework for automatically learning rules of a simple game of cards using data from a vision system observing the game being played. Incremental learning of object and protocol models from video, for use by an artificial cognitive agent, is presented. iLearn??a novel algorithm for inducing univariate decision trees for symbolic datasets is introduced. iLearn builds the decision tree in an incremental way allowing automatic learning of rules of the game.  相似文献   
3.
Pharmaceuticals are designed and used because of their specific biological effects. Over the past decade, compounds from various classes of pharmaceuticals have been detected in the environment. Concern has grown about the adverse effects pharmaceuticals in the environment might potentially have on human and ecological health. A sound risk assessment is therefore urgently needed for pharmaceuticals. Standardized tests for assessing the effects of chemicals on environmental organisms are widely used for this purpose. However it is questionable whether classical standardized tests give reliable data needed for environmental risk assessment. In this study we investigated the suitability of the respiration inhibition test OECD 209 for the assessment of the effects of antibiotics, disinfectants and cytotoxics on sewage sludge bacteria. We found that inhibition concentrations can strongly depend on the test period and the type of compound. We conclude that tests to assess the effects of pharmaceuticals on environmental organisms such as bacteria have to be evaluated before their results can be used in environmental risk assessment.  相似文献   
4.
For all new pharmaceuticals, an environmental risk assessment (ERA) has to be performed according to guidelines developed by the European Medicines Evaluation Agency. An important factor of this procedure is the assessment of the predicted environmental concentration in the aquatic environment, which is significantly influenced by the biodegradability of pharmaceuticals in sewage treatment plants. Established standardized methods for determining biodegradation under laboratory conditions apply to substance concentrations, which are much higherthan those expected in reality. Against this background, the laboratory scale sewage treatment plant (LSSTP), as described by the Organisation for Economic Cooperation and Development (OECD) Guideline No. 303A, was modified to construct a lossless system, which allows laboratory testing at realistic concentrations. To verify the experimental setup, the antibiotics benzylpenicillin, ceftriaxone, and trimethoprim were tested at low concentrations (microg/L) using 14C-labeled compounds. The results show that approximately 25% of benzylpenicillin was mineralized, whereas ceftriaxone and trimethoprim were not mineralized at all. Due to the high total recoveries of added radioactivity (> or =95%) and the fact that the findings comply with available literature data, the lossless operation of the test system could be proved. Consequently, the modified LSSTP is a suitable tool to determine more realistic biodegradation data required for the exposure assessment within the scope of an ERA for pharmaceuticals.  相似文献   
5.
The use of statins as the preferred lipid-lowering therapy has clearly demonstrated its efficacy in the treatment of hypercholesterolemia, reducing also the risk of coronary events and cardiovascular disease mortality. In this study, we assessed single nucleotide polymorphisms (SNPs) in the SLCO1B1 gene and their effect on atorvastatin response. We included 129 Chilean hypercholesterolemic patients undergoing 10 mg/day of atorvastatin therapy during 4 weeks. Lipid profile was determined before and after drug administration. Genotyping of SLCO1B1 rs4149056 (c.521T>C) SNP was performed with allele-specific polymerase chain reaction, whilst polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping the SLCO1B1 rs2306283 (c.388A>G) variant. After statin therapy, concentrations of TC, LDL-C and TG had a decrease from baseline (p < 0.05). Also, HDL-C levels increased (p < 0.05). Minor allele frequencies for the rs2306283 and rs4149056 variants were 0.547 and 0.136, respectively. LDL-C response to atorvastatin was not associated with the SLCO1B1 rs4149056 nor the rs2306283 polymorphisms (p > 0.05). However, the latter SNP was associated with HDL-C variability after atorvastatin medication (p = 0.02). This study indicates that LDL-C reduction following atorvastatin therapy is not influenced by the SNPs evaluated. In addition, the polymorphism rs2306283 at the SLCO1B1 gene determines greater HDL-C concentrations in response to atorvastatin medication in Chilean hypercholesterolemic subjects.  相似文献   
6.
Reviews the book, Grief—The mourning after by Catherine M. Sanders (see record 1989-97503-000). This book is a respectable addition to the grief and bereavement literature. Much of its contents are derived from an important two-year longitudinal study of 115 bereaved persons who incurred the death of a close family member. The author's appreciation of standardized and well-normed instruments (e.g., Grief Experience Inventory) and appropriate research methodology gives credence to the abundance of anecdotal material. Rather than simply being repetitive of earlier contributors such as Raphael, Parkes, Rando and others, the book, for the most part, reads as a fresh contribution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
7.
Blending of polyethylene with lignin in concentrations > 20 wt % yielded blends with relatively low mechanical properties. A new method, based on modification of polyethylene with ethylene–vinylacetate (EVA) copolymer, was developed for the preparation of polyethylene blends containing about 30 wt % lignin with acceptable strength properties. The addition of 10 wt % EVA caused an increase of tensile strength about twice and elongation at break about 13 times compared to those of the corresponding nonmodified samples. The optimization of lignin–polyethylene–EVA blend composition was based on a regression equation, which was obtained as output from an experimental design. The prepared composite material with 33.6 wt % lignin showed acceptable processing and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1855–1860, 2004  相似文献   
8.
42 bereaved parents (aged 28–66 yrs) were requested to (a) listen to an audiotaped testimony of a bereaved parent's experience in coping with the death of a child during the phases of numbing, yearning and searching for the lost figure, disorganization and despair, and reorganization; (b) discuss how their experience in coping with their child's death compared to what they listened to on tape; and (c) for each phase, complete the Scale of Counseling Dimension Preferences, which depicts preferences for action orientation or insight orientation, cognition or conation, and structure or ambiguity. Results suggest that bereaved parents have generalized preferences for counseling dimensions during different phases of grieving. Findings are discussed in terms of influences that facilitate the grieving process of bereaved parents during individual psychological counseling. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
The chemical composition determines plant-derived foods’ sensory traits; genetic and environmental effects and their interactions determine chemical composition. Understanding the importance of each factor should help characterise foodstuffs according to the variety and place of cultivation. We studied the effects of variety (five landraces + two checks) and environment (five locations and two years) on some molecules important for beans’ (Phaseolus vulgaris L.) sensory value. The greatest location effects were on protein and starch content and variety effects were due to combinations of traits (mainly sucrose, protein, and malic acid). The variety × location interactions detected in protein, sucrose, citric acid, and malic acid were difficult to associate to the gastronomic success of a particular variety cultivated at a particular location. Our results showed that protected designation of origin (PDO) in beans could be delimited on the basis of chemical composition, derived from the particular environmental characteristics of a region and the genetic characteristics of the varieties admitted.  相似文献   
10.
Reviews the book, The trauma response: Treatment for emotional injury by Diana S. Everstine and Louis Everstine (see record 1993-97113-000). The major premise of this book is that PTSD, as defined in the DSM-III-R, should be reconceptualized and recognized as "trauma response." This shift in focus emphasizes normalcy and a nonpathological recovery process as opposed to adherence to a disease model of psychological affliction in which a "disorder" is diagnosed and treated. The stated purpose of this book is to help clinicians identify, measure, and treat emotional trauma. This book is comprehensive and divided into four parts, covering topics such as the phenomenon of trauma, treatment for adult trauma, hidden trauma, trauma in the work place and trauma and the law. According to the reviewer, the book as a whole reflects valuable learning that has accrued from the authors' clinical experiences in working with victims of trauma. A diverse readership would benefit from this addition to the clinical literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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