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At least 973 records · Page 54Linked to original sources
PubMed2002

[Combustion characteristics of mixed municipal solid waste in thermogravimetric analysis and lab scale fluidized bed].

In this paper, thermogravimetric analysis (TGA) and a lab scale fluidized bed facility were used as experimental means. The data in the two different experimental systems were introduced and compared. Experimental results show that the differences of combustion velocity among different wastes in Fluidized Bed(FB) were very small whereas in thermogravimetric analyzer the differences can not be ignored as the value range of combustion velocity variation was between 0.49 and 5.5. It took municipal solid waste 3-3.5 min to burn out in FB, but in thermogravimetric analyzer, the time was 20-25 min. It can be concluded that, in general, the behavior of a mixture of waste in TGA can be expressed by simple combination of individual components of the waste mixtures. Only minor deviations from the rule were observed. In FB, it was found that, for some mixtures, there was interference among the components during FB combustion.

Hot Temperature↗
PubMed2005

Optimizing management of hirudin anticoagulation.

Accurate anticoagulation monitoring, critical during cardiac surgery (CS), is especially important for novel therapeutics such as hirudins, for which there are no known antidotes. The activated clotting time (ACT), which is standard for heparin monitoring, has been reported to be insufficiently sensitive to high levels of hirudins. A simple, accurate, and sensitive assay is needed to monitor hirudins at the levels required for CS. During the REPLACE/II clinical trials, the HEMOCHRON Jr. Signature ACT+ was used to monitor Angiomax during percutaneous cardiac intervention (PCI) procedures and was observed to lose sensitivity at bivalirudin concentrations greater than 8-10 microg/mL. A new assay, the ACTT, was developed to increase the linear sensitivity of the ACT+ over the range of 15-30 microg/mL bivalirudin to extend the clinical utility of the assay to CS levels. Both in vitro and ex vivo studies were performed using the ACTT and ACT+. In vitro ACT+ and ACTT clotting times, identical for bivalirudin levels up to approximately 5 microg/mL, diverged from each other near 10 microg/mL. The ACTT showed excellent linearity to bivalirudin at concentrations up to 30 microg/ mL. Reproducibility was also superior with coefficients of variation <15% across 13 donors at clotting times <760 seconds. The ACTT was evaluated for monitoring bivalirudin during PCI in 67 patients. The ex vivo comparison of ACTT to ACT+ <340 seconds, showed a slope near 1.0 and an average difference between the tests of 5%. At higher clotting times this slope increased to near 3.0, with an average difference between tests of 20%. These data suggest that the ACTT displays increased sensitivity to high levels of bivalirudin.

Angioplasty, Balloon, Coronary↗
PubMed1995

Molecular cloning, sequencing, and expression in Escherichia coli of the chalcone synthase gene.

Flavonoids form a class of secondary metabolites that are abundant in all higher plants. They serve important functions in flower pigmentation. Chalcone Synthase (CHS) is a key enzyme in the biosynthesis of all classes of flavonoids; therefore, variation of the expression of CHS might change the color of flowers. We cloned CHS-A gene from Petunia hybrida, which has 99% sequence homology with those that have been cloned abroad. The sequence of the coding region is 1170bp and encodes a protein of 39kDa. CHS-A gene is also expressed high-efficiently in E. coli. All this work establishes a sound basis for future research on the impact of the CHS-A gene on flower pigmentation.

Acyltransferases↗
PubMed1991

Immunohistochemical characterization of the lymphocyte and the immunoglobulin-containing cell in the epithelium and the lamina propria of normal human intestines.

In order to clarify difference of the mucosal immunity in various sites of normal large and small intestines, we studied the population of lymphocyte subsets and immunoglobulin (Ig)-containing cells in situ in biopsy specimens taken from various sites (ascending colon, sigmoid colon and rectum) of the large intestine and from the duodenum using an immunohistochemical method. Monoclonal antibodies against pan-T (Leu 1), cytotoxic/suppressor T (Leu2a), helper/inducer T (Leu3a), suppressor T (Leu15) and natural killer/K (Leu7) cells, and polyclonal antibodies to human IgG, IgA and IgM were used. In the duodenum, intraepithelial lymphocytes (IELs) were more prominent than in the large intestine. Immunoelectron microscopic observation revealed that some Leu2a+ IELs possessed pseudopods extending into intestinal epithelial cells, indicating that some IELs belong to the cytotoxic T cell subset. Leu7+ IELs were scarcely observed and Leu7+/Leu1+ ratio was higher in the large intestine than in the duodenum. Furthermore, the number of Leu7+ cells were more in the distal than the proximal colon. In the lamina propria Ig-containing cells tended to be fewer in the rectum than in the duodenum and the proximal colon. Our findings may suggest the variation of local immune responses and the difference of assigned immunological functions among the various sites of the intestines.

Adult↗
PubMed1995

Application of high field spectroscopic imaging in the evaluation of temporal lobe epilepsy.

Previous spectroscopic imaging studies of temporal lobe epilepsy have used comparisons of metabolite content or ratios to lateralize the seizure focus. Although highly successful, these studies have shown significant variations within each of the groups of healthy subjects and patients. This variation may arise from the natural differences seen in metabolite concentration in gray and white matter, the complex anatomy seen about the hippocampus, and the large voxels typically employed at 1.5 T. Using a 4.1 T whole body system, we have acquired spectroscopic images with 0.5 cc nominal voxels (1 cc after filtering) to evaluate the regional variation in metabolite content of the hippocampus, temporal gray and white matter, midbrain, and cerebellar vermis. Using a threshold value of 0.90 for CR/NAA, a value 90% of all normal hippocampal voxels lay below, we have correctly identified the presence of epileptogenic tissue in patients with unilateral as well as bilateral seizures. By using comparisons to healthy values of the CR/NAA ratio, this method enables the visualization of bilateral disease and provides information on the extent of gray matter involvement.

Aspartic Acid↗
PubMed2006

Is the uniform electron gas limit important for small Ag clusters? Assessment of different density functionals for Ag(n) (n < or = 4).

Twenty-three density functional theory (DFT) methods, including the second- and the third-generation functionals, are tested in conjunction with two basis sets (LANL2DZ and SDD) for studying the properties of neutral and ionic silver clusters. We find that DFT methods incorporating the uniform electron gas limit in the correlation functional, namely, those with Perdew's correlation functionals (PW91, PBE, P86, and TPSS), Becke's B95, and the Van Voorhis-Scuseria functional VSXC, generally perform better than the other group of functionals, e.g., those incorporating the LYP correlation functional and variations of the B97 functional. Strikingly, these two groups of functionals can produce qualitatively different results for the Ag3 and Ag4 clusters. The energetic properties and vibrational frequencies of Ag(n) are also evaluated by the different functionals. The present study shows that the choice of DFT methods for heavy metals may be critical. It is found that the exact-exchange-incorporated PBE functional (PBE1PBE) is among the best for predicting the range of properties.

Journal Article↗
PubMed2005

Cross-host evolution of severe acute respiratory syndrome coronavirus in palm civet and human.

The genomic sequences of severe acute respiratory syndrome coronaviruses from human and palm civet of the 2003/2004 outbreak in the city of Guangzhou, China, were nearly identical. Phylogenetic analysis suggested an independent viral invasion from animal to human in this new episode. Combining all existing data but excluding singletons, we identified 202 single-nucleotide variations. Among them, 17 are polymorphic in palm civets only. The ratio of nonsynonymous/synonymous nucleotide substitution in palm civets collected 1 yr apart from different geographic locations is very high, suggesting a rapid evolving process of viral proteins in civet as well, much like their adaptation in the human host in the early 2002-2003 epidemic. Major genetic variations in some critical genes, particularly the Spike gene, seemed essential for the transition from animal-to-human transmission to human-to-human transmission, which eventually caused the first severe acute respiratory syndrome outbreak of 2002/2003.

Amino Acid Substitution↗
PubMed2003

Natural selection on the olfactory receptor gene family in humans and chimpanzees.

The olfactory receptor (OR) genes constitute the largest gene family in mammalian genomes. Humans have >1,000 OR genes, of which only approximately 40% have an intact coding region and are therefore putatively functional. In contrast, the fraction of intact OR genes in the genomes of the great apes is significantly greater (68%-72%), suggesting that selective pressures on the OR repertoire vary among these species. We have examined the evolutionary forces that shaped the OR gene family in humans and chimpanzees by resequencing 20 OR genes in 16 humans, 16 chimpanzees, and one orangutan. We compared the variation at the OR genes with that at intergenic regions. In both humans and chimpanzees, OR pseudogenes seem to evolve neutrally. In chimpanzees, patterns of variability are consistent with purifying selection acting on intact OR genes, whereas, in humans, there is suggestive evidence for positive selection acting on intact OR genes. These observations are likely due to differences in lifestyle, between humans and great apes, that have led to distinct sensory needs.

Animals↗
PubMed2001

Regional differences in intramyocellular lipids in humans observed by in vivo 1H-MR spectroscopic imaging.

Regional differences in the content of intramyocellular lipids (IMCL), extramyocellular lipids, and total creatine (TCr) were quantified in soleus (S), tibialis posterior (TP), and tibialis anterior (TA) muscles in humans using in vivo 1H proton spectroscopic imaging at 4 T. Improved spatial resolution (0.25-ml nominal voxel resolution) made it feasible to measure IMCL in S, TP, and TA simultaneously in vivo. The most significant regional difference was found in the content of IMCL compared with extramyocellular lipids or TCr. The concentrations of TCr were found to be 29-32 mmol/kg, with little regional variation. IMCL content was measured to be 4.8 +/- 1.6 mmol/kg tissue wt in S, 2.8 +/- 1.3 mmol/kg tissue wt in TP, and 1.6 +/- 0.9 mmol/kg tissue wt in TA in the order of S > TP > TA (P < 0.05). It is likely that these IMCL values are consistent with the known fiber types of these muscles, with S having the greatest fraction of type I (slow-twitch, oxidative) fibers and TA having a large fraction of type IIb (fast-twitch, glycolytic) fibers.

Adult↗
PubMed1997

Comparative metabolism of the antiviral dimer 3'-azido-3'-deoxythymidine-P-2',3'-dideoxyinosine and the monomers zidovudine and didanosine by rat, monkey, and human hepatocytes.

AZT-P-ddI is an antiviral heterodimer composed of one molecule of 3'-azido-3'-deoxythymidine (AZT) and one molecule of 2',3'-dideoxyinosine (ddI) linked through their 5' positions by a phosphate bond. The metabolic fate of the dimer was studied with isolated rat, monkey, and human hepatocytes and was compared with that of its component monomers AZT and ddI. Upon incubation of double-labeled [14C]AZT-P-[3H]ddI in freshly isolated rat hepatocytes in suspension at a final concentration of 10 microM, the dimer was taken up intact by cells and then rapidly cleaved to AZT, AZT monophosphate, ddI, and ddI monophosphate. AZT and ddI so formed were then subject to their respective catabolisms. High-performance liquid chromatography analyses of the extracellular medium and cell extracts revealed the presence of unchanged dimer, AZT, 3'-azido-3'-deoxy-5'-beta-D-glucopyranosylthymidine (GAZT), 3'-amino-3'-deoxythymidine (AMT), ddI, and a previously unrecognized derivative of the dideoxyribose moiety of ddI, designated ddI-M. Trace extracellular but substantial intracellular levels of the glucuronide derivative of AMT (3'-amino-3'-deoxy-5'-beta-D-glucopyranosylthymidine [GAMT]) were also detected. Moreover, the extent of the formation of AMT, GAZT, and ddI-M from the dimer was markedly lower than that with AZT and ddI alone by the hepatocytes. With hepatocytes in primary culture obtained from rat, monkey, and human, large interspecies variations in the metabolism of AZT-P-ddI were observed. While GAZT and ddI-M, metabolites of AZT and ddI, respectively, as well as AZT 5'-monophosphate (MP) and ddI-MP were detected in the extracellular media of all species, AMT and GAMT were produced only by rat and monkey hepatocytes. No such metabolites were formed by human hepatocytes. The metabolic fate of the dimer by human hepatocytes was consistent with in vivo data recently obtained from human immunodeficiency virus-infected patients.

Animals↗
PubMed2005

The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form.

Many human craniofacial dimensions are largely of neutral adaptive significance, and an analysis of their variation can serve as an indication of the extent to which any given population is genetically related to or differs from any other. When 24 craniofacial measurements of a series of human populations are used to generate neighbor-joining dendrograms, it is no surprise that all modern European groups, ranging all of the way from Scandinavia to eastern Europe and throughout the Mediterranean to the Middle East, show that they are closely related to each other. The surprise is that the Neolithic peoples of Europe and their Bronze Age successors are not closely related to the modern inhabitants, although the prehistoric/modern ties are somewhat more apparent in southern Europe. It is a further surprise that the Epipalaeolithic Natufian of Israel from whom the Neolithic realm was assumed to arise has a clear link to Sub-Saharan Africa. Basques and Canary Islanders are clearly associated with modern Europeans. When canonical variates are plotted, neither sample ties in with Cro-Magnon as was once suggested. The data treated here support the idea that the Neolithic moved out of the Near East into the circum-Mediterranean areas and Europe by a process of demic diffusion but that subsequently the in situ residents of those areas, derived from the Late Pleistocene inhabitants, absorbed both the agricultural life way and the people who had brought it.

Anthropometry↗
PubMed2005

Evidence of balancing selection at the HLA-G promoter region.

HLA-G is a class Ib HLA gene with unique tissue expression pattern and immunomodulatory properties. Polymorphisms in the HLA-G promoter region have been associated with miscarriage and asthma, whereas expression levels have been associated with a wide range of pathologic conditions as well as survival of embryos after in vitro fertilization and of organs after transplantation. Here, we characterize the sequence variation and haplotype structure of the HLA-G promoter and flanking sequences in 44 African Americans, 47 European Americans and 43 Han Chinese by haplotype-specific PCR and sequencing. In all three populations, we observed high levels of nucleotide variation, an excess of intermediate-frequency alleles, and a genealogy with two common haplotypes separated by deep branches, features that are suggestive of balancing selection acting in this region. Comparisons to HLA-A and a pseudogene, HLA-J, suggested that the observed pattern of sequence variation in the HLA-G promoter region is not likely due to other selected HLA genes. We suggest that the mechanism for this selection is related to the highly regulated expression pattern of HLA-G and that high- and low-expressing promoters may be favored under temporally and/or spatially varying selective pressures.

Black or African American↗
PubMed2000

Elliptical fourier analysis of symphyseal shape in great ape mandibles.

The midsagittal profile of the mandibular symphysis has served as both a taxonomic marker and a phylogenetically salient character in debates over hominoid evolution. Nevertheless, the utility of symphyseal shape as an informative attribute for paleobiological reconstructions is suspect. Quantification of shape variation has proven to be particularly problematic; it has long been recognized that conventional linear measurements (and the indices derived from them), while replicable, summarize aspects of shape very poorly because of the vast amount of contour information that is lost in the process. In this study, a type of Fourier analysis is applied to cross-sectional contours of ape mandibles in order to provide a mathematical accounting of shape variation in a "global" sense; that is, by applying the "totality" of contour information in a comparative analysis. Shape variation in the mandibular symphysis is explored through the decomposition of coordinate data into elliptical Fourier coefficients. These coefficients are used to compute average taxonomic distances (ATD) among individuals of chimpanzees, gorillas, and orang-utans. The resulting shape-based distances are summarized via clustering (UPGMA) and ordination (principal coordinates analysis-PCO). Principal coordinate scores are subjected to analysis of variance in univariate and multivariate designs; these data are also applied to discriminant function analyses. Species and sex effects on morphology are statistically significant; however, no significant interaction of these factors is indicated. This would seem to imply that patterns of sexual dimorphism are not distinct among great apes; to the contrary, within-species sex comparisons reveal that significant size and shape dimorphism is present only in Gorilla. Despite significant size dimorphism in Pan and Pongo, significant shape differences between males and females are not apparent in these taxa. These results suggest that it is theoretically possible to sort taxa by a symphyseal shape criterion, but the discriminant function results suggest that there still exists a large potential for error in assigning particular shapes to a given species or sex. Thus, despite real shape differences among these species, the use of symphyseal shape as a character in species identification or in systematic arguments remains limited and problematic.

Analysis of Variance↗
PubMed2002

Validation of a new whole blood coagulation monitoring system.

The Hemochron Response is a third generation point-of-care (POC) whole blood coagulation analyzer that retains the clinical utility of the Hemochron standard (801/8000) while providing a data management program that assists the POC coordinator with Quality Assurance (QA) compliance. Clinical and laboratory studies were performed to ensure consistency of the target anticoagulation times with the Hemochron standard and to evaluate precision and reproducibility of the Hemochron Response. Clinical tests for prothrombin time (PT) using fresh and citrated whole blood, activated clotting time (ACT), and activated partial thromboplastin time (APTT) showed excellent correlation to the Hemochron standard where r = 0.929, r = 0.969, r = 0.947, and r = 0.992, respectively. This was confirmed by a paired Student's t-test. The standard expectation for reproducibility of ACT tests has been a coefficient of variation (CV) of 10%. Laboratory studies of reproducibility and precision for the Response instrument included analysis of the CV using ACT test tubes. For normal and abnormal control plasma (CPL), the range of CVs observed was 3.3%-4.6% and 3.0%-5.0%, respectively. For heparin dose response analysis, the range for Donor 1 and 2 was 1.0%-4.2% and 1.1%-8.0%, respectively. These data suggest that the Hemochron Response is reliable and equivalent to the Hemochron standard in clinical applications.

Autoanalysis↗
PubMed2006

[Nuclear ribosomal DNA internal transcribed spacer 1 sequences of 4 Leonurus species].

OBJECTIVE: To analyze the nuclear ribosome DNA (nrDNA) internal transcribed spacer (ITS) sequences of 4 Leonurus species, and the possibility of using them for molecular authentication of the crude drugs from the genus. METHODS: The nrDNA ITS sequence (including ITS1, 5.8S rDNA, ITS2, and partial 18S rDNA and 26S rDNA) of L. japonicus and its 3 adulterant species were amplified and sequenced, and CLUSTRAL X and MEGA software was employed for analysis. RESULTS: The variation of ITS1 and ITS2 between L. japonicus and its adulterant species ranged between 7.2% and 18.8% and between 14.2% and 27%, respectively. The phylogenic tree derived from the dendrograms based on the ITS sequence data contained some discrepancy from the traditional classification. CONCLUSION: The nrDNA ITS sequences can be used potentially as efficient markers for identification of L. japonicus and its adulterants, and further study is needed for studying the phylogeny of Leonurus.

DNA, Plant↗
PubMed1992

Quantitation of human IgG subclass antibodies to Haemophilus influenzae type b capsular polysaccharide. Results of an international collaborative study using enzyme immunoassay methodology.

An international collaborative study was conducted at ten sites to examine the performance of enzyme immunoassays (EIAs) for the quantitation of IgG1, IgG2, IgG3, IgG4 and total IgG anti-Haemophilus influenzae type b (Hib) capsular polysaccharide in human serum. All groups used the same reagents: microtiter plates coated with polyribosylribitol phosphate (PRP) conjugated to poly-L-lysine (PLL), reference, control and test human sera, biotin-conjugated International Union of Immunological Societies (IUIS)-documented monoclonal anti-human IgG1-4 and IgG Pan detection antibodies, avidin-peroxidase and TMB substrate. Initial mixing of soluble PRP antigen or an equal volume of buffer with the 20 test sera prior to analysis confirmed PRP antigen specificity in all five EIAs with greater than 80% competitive inhibition at most sites. Positive correlation between the total IgG anti-Hib and sum of IgG1-4 anti-Hib was demonstrated (r2 = 0.99, Y = 1.13X -0.15). Good agreement was shown between the total IgG anti-Hib as measured by EIA and the total Hib-specific antibodies measured by the current radiolabeled antigen binding assay (r2 = 0.97, Y = 4.6X -5.8). Assay parallelism was demonstrated with an average interdilutional %CV of 22% and parallel dose-response curve slopes. The interdilutional %CVs were calculated as an average per sample of the variation of microgram/ml (corrected for dilution) at different dilutions per laboratory for all participating sites. The interlaboratory variation was the only performance parameter studied that exceeded the target level of 35% CV in all IgG1-4 and total IgG anti-Hib assays. IgG subclass distributions in the test sera demonstrated a predominance of IgG1 anti-Hib in the pediatric serum pools and IgG2 anti-Hib in the adult sera, with low but detectable levels of IgG3 and IgG4 anti-Hib in each group.

Adult↗
PubMed2004

Relationships between the fossil colobine Mesopithecus pentelicus and extant cercopithecoids, based on dental metrics.

Maxillary dental measurements from six specimens of Mesopithecus pentelicus, 64 cercopithecines, 59 African colobines, and 64 Asian colobines were analyzed by means of a "nested research design" that was specifically designed to explore the affiliation between fossils and extant cercopithecoids at different systematic levels. The results showed that the variation among taxonomic groups was mainly associated with size; however, in addition, interesting shape differences emerged, molars were shown to be important discriminators, Mesopithecus was confirmed as a colobine (as expected) and found to be closer to Asian species than to African ones, and the odd-nosed colobines were found to share more dental similarities with Mesopithecus than other colobines. The last finding is in contrast to previous studies, in which it was proposed that M. pentelicus is morphologically closely related to the African colobus and the gray langur (Semnopithecus).

Africa↗
PubMed2006

Different evolutionary fates of recently integrated human and chimpanzee LINE-1 retrotransposons.

The long interspersed element-1 (LINE-1 or L1) is a highly successful retrotransposon in mammals. L1 elements have continued to actively propagate subsequent to the human-chimpanzee divergence, approximately 6 million years ago, resulting in species-specific inserts. Here, we report a detailed characterization of chimpanzee-specific L1 subfamily diversity and a comparison with their human-specific counterparts. Our results indicate that L1 elements have experienced different evolutionary fates in humans and chimpanzees within the past approximately 6 million years. Although the species-specific L1 copy numbers are on the same order in both species (1200-2000 copies), the number of retrotransposition-competent elements appears to be much higher in the human genome than in the chimpanzee genome. Also, while human L1 subfamilies belong to the same lineage, we identified two lineages of recently integrated L1 subfamilies in the chimpanzee genome. The two lineages seem to have coexisted for several million years, but only one shows evidence of expansion within the past three million years. These differential evolutionary paths may be the result of random variation, or the product of competition between L1 subfamily lineages. Our results suggest that the coexistence of several L1 subfamily lineages within a species may be resolved in a very short evolutionary period of time, perhaps in just a few million years. Therefore, the chimpanzee genome constitutes an excellent model in which to analyze the evolutionary dynamics of L1 retrotransposons.

5' Untranslated Regions↗