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Recycling has emerged as an environmental key point due to the diminishing of natural resources and the generation of ever-increasing amounts of industrial solid wastes. Glass wastes are among the materials that attract great interest in the recycling concept. This work presents the results of foams production from four series of compositions. The first series comprises powders of a sodium-calcium-silicate sheet glass cullet as the main component, an alkali-earth aluminosilicate glass as an additive, and a reagent grade silicon carbide (SiC) powder as gassing agent. In the second series, the glass cullet was used in combination with fly ashes (FLA) as main components, while SiC waste from abrasive paper served as foaming agent. In the third and fourth series, carbonates (calcite and dolomite) were used for foaming powder mixtures composed of sheet glass cullet and FLA, and powdered cathode ray tube panel glasses, respectively. All the processing parameters, including the main components, the nature and content of foaming agents are shown to play a crucial role on the foaming ability and final properties of the glass foams.  相似文献   
84.
Concerned about environmental pollution, and aware of the comfort that polyethylene provides for daily human life, this work sought to replace a percentage of high-density polyethylene (HDPE) with human or bovine hair. Hair is natural, abundant, light weight, non-toxic, and disposed of as garbage. The main disadvantage of natural composites is the interfacial adhesion. To increase the interfacial adhesion between hair and HDPE, stearic acid or oleic acid was chemically anchored on the hair surface, which leads to an improved contact angle hysteresis and hydrophobicity. Dynamic-mechanical properties of the composites were investigated focusing on the type of carboxylic acid used (stearic or oleic acid), hair length, hair type (human or bovine) and amount of hair used in the composite. Taking 40°C as a reference, using 15% of hair with a length of 1 ± 0.15 mm, the highest storage modulus value was obtained with HDPE with human hair modified with oleic acid, exceeding the value of the storage modulus of HDPE by 67.64%. Increasing storage modulus on composites indicates of interfacial interaction and chemical affinity improvement between hair and polyethylene.  相似文献   
85.
A new class of potent dopamine D(4) antagonists was discovered with selectivity over dopamine D(2) and the alpha-1 adrenoceptor. The lead compound was discovered by screening our compound collection. The structure-activity relationships of substituted isoindoline rings and the chirality about the hydroxymethyl side chain were explored. The isoindoline analogues showed modest differences in potency and selectivity. The S enantiomer proved to be the more potent enantiomer at the D(4) receptor. Several analogues with greater than 100-fold selectivity for D(4) over D(2) and the alpha-1 adrenoreceptor were discovered. Several selective analogues were active in vivo upon oral or intraperitoneal administration. A chiral synthesis starting from either D- or L-O-benzylserine is also described.  相似文献   
86.
AM1 calculations are reported for enines with aromatic substituents. It was found that the position of the unsaturated bonds in each molecule may account for the reactivity of each isomer via different polymerization pathways. The resonant structure of the charged form of one of the molecules allowed speculation about the observed inhibition of the polymerization reaction.  相似文献   
87.
88.
In order to identify risk of inadequate intake of calories and nutrients during pregnancy, 75 pregnant adolescents (14 to 18 years old) apparently healthy, from low socioeconomic level, in their first prenatal control (12 weeks) were studied by two 24 hour recalls and a food frequency questionnaire at each trimester. Nutritional status was assessed by body mass index (pregestation weight/height) and classified according to American Medicine Institute reference. Paired t-test, frequency distribution and ANOVA were used for statistical analysis. Low weight was found in 34.6% of adolescent at the first visit and 5.3% were overweight. Even though, caloric intake was below recommendation, significant increases were observed between first and second trimester for energy, carbohydrates, niacin and zinc (p < 0.001) and for fat, proteins, riboflavin, thiamin, vitamin C, calcium and iron (p < 0.05). From second to third trimester, differences (p < 0.05) were significant only for vitamin A. Between first and third trimester, differences were significant (p < 0.05) for energy, proteins, carbohydrates, niacin, riboflavin, zinc and for thiamin, vitamin A and calcium (p < 0.05). A high proportion of pregnant adolescent did not reach recommendations for energy, folate, calcium and zinc. Food intake pattern did not change significantly among trimesters. Mean total weight gain was 9.2 kg and 0.412 +/- 0.4 g/week. Newborn's mean weight was 3.221 +/- 418 grams. It is concluded that adolescents are at high nutritional risk and deficiency of dietary intake should be followed. Attention should be addressed from the preconceptional period to postpartum in order to improve maternal and fetal conditions.  相似文献   
89.
Differential pressure fluctuations were studied along the wall of a laboratory scale column filled with a polyethylene resin. Air flow rates to the column were varied in order to examine the changes in wall pressure with respect to superficial gas velocity. Statistical and spectral analysis was used to study the periodic features of column wall pressure measurements in the dense region of a fluidized bed. From the analysis, it is evident that multiple flow regimes exist in the column. These flow regimes are dependent upon the height above the distributor. Results also show a significant peak developing at 1 Hz as superficial gas velocity increases.  相似文献   
90.
Mammary neoplasms are the tumors most affecting female dogs and women. Formalin-fixed, paraffin-embedded (FFPE) tissues are an invaluable source of archived biological material. Fresh frozen (FF) tissue is considered ideal for gene expression analysis. However, strategies based on FFPE material offer several advantages. Branched-DNA assays permit a reliable and fast workflow when analyzing gene expression. The aim of this study was to assess the comparability of the branched-DNA assay when analyzing certain gene expression patterns between FF and FFPE samples in canine mammary tumors. RNA was isolated from 109 FFPE samples and from 93 FF samples of different canine mammary tissues. Sixteen (16) target genes (Tp53; Myc; HMGA1; Pik3ca; Mcl1; MAPK3; FOXO3; PTEN; GATA4; PFDN5; HMGB1; MAPK1; BRCA2; BRCA1; HMGA2; and Her2) were analyzed via branched-DNA assay (b-DNA). ACTB, GAPDH, and HPRT1 were used as data normalizers. Overall, the relative gene expression of the two different origins of samples showed an agreement of 63%. Still, care should be taken, as FFPE specimens showed lower expression of the analyzed targets when compared to FF samples. The fact that the gene expression in FFPE proved to be lower than in FF specimens is likely to have been caused by the effect of storage time. ACTB had the best performance as a data normalizer.  相似文献   
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