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At least 217 records · Page 12Linked to original sources
PubMed1991

The electron impact, chemical ionization and fast atom bombardment positive ion mass spectra of 1,2-bis(sulfonyl)methylhydrazines.

A series of bis(sulfonyl)-1-methylhydrazines were analyzed by positive ion electron impact (EI), chemical ionization (CI) and fast atom bombardment (FAB) mass spectrometry. Since these compounds showed activity against the L1210 leukemia, an understanding of their mass spectral behavior is important should the structural characterization of metabolites be required. FAB proved to be the most useful technique, generally providing abundant protonated molecule ion peaks, in contrast to the weak peaks observed with CI (ammonia or isobutane) and the total absence of molecular ion peaks in the EI mass spectra. In addition, utilizing FAB eliminated the problem of thermal decomposition, which was very difficult to control under EI and CI experimental conditions. Fragments observed in FAB and CI mass spectra were consistent with protonation at the methyl-bearing nitrogen. One can locate the R1 and R2 moieties relative to the methyl-bearing nitrogen in FAB and CI by assigning that nitrogen as the site of protonation, with subsequent elimination of R2SO2H.

Antineoplastic Agents↗
PubMed1996

Psychological perspective for a theory of behavior during riots.

In a riot situation some individuals actively participate in antisocial behavior, but others do not, and still others act to discourage hostile activity. Four concepts from general psychology including (1) insufficiency of internal control or lack of internalized restraints acquired through learning, (2) effects of frustration, (3) emotional excitement, and (4) precipitating incidents (one or more) are proposed as contributors to the behavioral involvement of participants. Some hypotheses and the role of such variables as emotional contagion, imitation, opportunism, and anonymity are discussed.

Antisocial Personality Disorder↗
PubMed2004

Effects of bird age, density, and molt on behavioral profiles of two commercial layer strains in cages.

Two commercial strains, Hy-Line W-36 and DeKalb XL, were moved to a laying house at 18 wk of age. They were housed 6 hens/layer cage at 2 densities (361 and 482 cm2/bird) with 2 replications each per strain/density combination. The high-density treatment contained 24 hens/replication and the low-density treatment contained 18 hens/replication for a total of 168 hens. Production parameters were measured during the first egg production cycle, the molt period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Behavioral observations were taken during 2 consecutive d at 26, 34, 43, 51, 62, 64, and 68 wk of age to examine behavioral patterns. Modified Hansen's tests were conducted concurrently to provide indication of the fearfulness levels of hens at the various stages of production. The production characteristics were similar for both strains. The hens kept at the higher density had lower (P < 0.01) hen-day production and (P < 0.05) daily egg mass. Appetitive behaviors were not affected by strain or density but were affected by the age of the hen and by molting. During the molt, feeding and drinking behavioral acts were fewer (P < 0.05) at 0.018 and 0.013 acts per bird/min, respectively, and standing behavior was highest. The results indicated that the frequencies of pecking inedible objects during the molt period were similar to the frequencies at 26 and 34 wk. Hens performed more acts of standing, and crouching and had lower frequency of movement during the molt. Those kept at a low density performed more movement acts. Feather pecking decreased as hens aged and increased when they molted but was not affected by strain or density. The frequency of aggression and submissive acts was significantly lower during the molt period. Behaviors were affected by strain, density, bird age, and molting; however, the patterns and number of aggressive acts did not increase to compromise the welfare status of the hens. Behaviors during the molt appeared consistent with mechanisms for conservation of body reserves.

Age Factors↗
PubMed1979

The Ocean-Hill Brownsville and Cambodian-Kent State crises: a biobehavioral approach to human sociobiology.

The author traces the origin of his thinking on a biobehavioral systems approach to human sociobiology as it evolved from his observations and analyses of on-the-ground human behavior in local, Ocean-Hill Brownsville, and nationwide, Cambodia-Kent State, political crises, as well as from his naturalistic observations of face-to-face behavior in group psychotherapy. He argues that the resulting sociobiological paradigm--arrived at independently by several other workers--is a fruitful alternative to sociobiological models derived from population biology and genetics.

Biology↗
PubMed2005

Sensitive determination of G-protein-coupled receptor binding ligands by solid phase extraction-electrospray ionization-mass spectrometry.

High affinity Histamine H2-receptor binding ligands were assayed by automated solid phase extraction (SPE) coupled via electrospray ionization with a Quadrupole-Time-of-Flight mass spectrometer (Q-ToF-MS). The mass spectrometric behavior of these analytes was tested in aqueous solutions with several (nine) volatile salts, in different pH, and with various methanol contents. Out of the high amount of available ligands, three fluorescent-labeled molecules (5706, 5707, and 5708) were studied in detail. The limits of detection (LODs) for all three compounds obtained in mass spectrometric detection was 1 fmol (absolute) in continuous flow and FIA (flow injection analysis) measurements. The results obtained with FIA-fluorescence detection gave LODs a factor 10-100 times higher. A systematic investigation of sample solving conditions, loading flow conditions, and elution flow conditions made the automated SPE-MS coupling efficient. Ideally, the ligands were dissolved in MeOH-25 mM phosphate buffer (30:70 v/v; pH 11), the SPE loading flow comprised MeOH-25 mM phosphate buffer (30:70 v/v; pH 11) and the SPE elution flow contained MeOH-100 mM ammonium formate solution (90:10 v/v; pH 3). Using this method on a C18-modified silica cartridge (C18, 5 microm, 100 A, 300 microm i.d. x 5 mm, LC Packings) assures high recovery and achieved LODs for all three compounds of 5 fmol (absolute). As an absolute amount of ligands specifically bound on H2-receptors in biochemical experiments is, as will be published elsewhere, between 10 and 100 fmol, the SPE-MS method for the basic compounds can be directly applied for these Histamine H2-receptors.

Buffers↗
PubMed1989

Numerical and experimental demonstrations of the need for caution in the use of zonal gel chromatography for characterizing ligand interactions with small acceptors.

Quantitative expressions are presented for the evaluation of equilibrium constants for interactions of the type A + B in equilibrium C from experiments entailing the application of a small zone of acceptor-ligand mixture to a column of gel preequilibrated with ligand solution [J.P. Hummel and W.J. Dreyer (1962) Biochim. Biophys. Acta 63, 530-532]. Only in the event that identical elution volumes pertain to acceptor and complex does the steady-state binding constant (Kss) obtained by that method equal the thermodynamic equilibrium constant (K). Simulated elution profiles are then generated with parameters relevant to gel chromatography of the ATP-Mg2+ system on Sephadex G-10 in order to demonstrate the practical importance of the need for distinction between Kss and K in situations where acceptor and complex do not comigrate. A study of the interaction between soybean trypsin inhibitor and cytochrome c by gel chromatography on Sephadex G-75 is then used to illustrate the feasibility of combining information from Hummel-Dreyer experiments with the theoretical expressions to characterize systems under the more general conditions that the elution volumes of A and C differ. A finding of considerable theoretical interest in relation to the simulation of mass migration behavior is the demonstration that a truncation error is the source of zonal spreading in the theoretical-plate model of chromatography. This truncation error is shown to be the source of spreading generated whenever solution of an abbreviated (diffusion-free) continuity equation involves substituting first differences for first derivatives in the differential equation describing mass transport.

Adenosine Triphosphate↗
PubMed2005

Impurity formation studies with peptide-loaded polymeric microspheres Part II. In vitro evaluation.

Since acylated peptide impurities were isolated from octreotide microspheres following incubation in an in vivo environment, the present investigation was undertaken to determine the dosage form dynamics responsible for facilitating acylation. In particular, microsphere batches made with poly(L-lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) 85:15 were studied for in vitro drug release, mass balance relationships, mass loss behavior, hydration uptake, and solid-state stability. Furthermore, native octreotide was incubated in a varying pH stability model (heat treated lactic acid solutions 42.5%, w/w) to determine the effects of acidity on impurity formation. From a review of the experimental results, the appearance of octreotide impurities or related substances occurred with the onset of polymeric mass loss. In fact, the significant formation of acylated peptide did not appear until >90% mass loss, which was observed at 14 days. It was surmised that because of water uptake, the hydrolytic cleavage of the polymeric backbone created an acidic microenvironment to facilitate the covalent coupling of peptide with polymer. The lactic acid solution stability model corroborated with greater evidence of acylation at pH 2.25 where the presence lactoyl (+72 m/z) derivatives of octreotide were confirmed by MALDI-TOF mass spectrometry.

Acylation↗
PubMed2003

[Risk factors related with eating disorders in a community of adolescents].

OBJECTIVE: To detect risk factors related with eating disorders. DESIGN: Descriptive, cross-sectional study. SETTING: 5 secondary schools in the Virgen de Rocío health area in Seville, Spain. PARTICIPANTS: 789 students enrolled in the first and second years of compulsory secondary school, and their families. MAIN MEASURES. Body mass index, risk behaviors related with food and exercise, influence of the mass media on models of desirable body types, and family climate. Data were obtained with three validated questionnaires: the Eating Attitudes Test (EAT-40), the CIMEC-26, and the Family Environment Scale (FES). RESULTS: In 6.9% of the participants, BMI was between 15 and 17, reflecting slight malnutrition. On the EAT scale, 68 participants (8.8%) had scores that were indicative of illness or risk of illness, and 25 (3.3%) could be diagnosed as having eating behavior disorder according to DSM-IV criteria. According to the CIMEC questionnaire, 104 participants (13.5%) were found to be significantly vulnerable to media pressures, and 85 (11.1%) were considered highly vulnerable. Parents' comments on eating behavior were related with the results on the EAT-40 CIMEC questionnaires (P=.01). No statistically significant relationship was found between family climate scores and the scores on the EAT-40 or CIMEC questionnaires. Students in rural or suburban area schools scored higher on the EAT-40 (P=.04) and CIMEC (P=.01) than students in urban or city center schools. CONCLUSION: The identification of persons considered at risk will allow us to use primary prevention programs more efficiently.

Adolescent↗
PubMed2003

Controlling the spatial distribution of ECM components in degradable PEG hydrogels for tissue engineering cartilage.

In developing a scaffold to support new tissue growth, the degradation rate and mass loss profiles of the scaffold are important design parameters. In this study, hydrogels were prepared by copolymerizing a degradable macromer, poly(lactic acid)-b-poly(ethylene glycol)-b-poly(lactic acid) endcapped with acrylate groups (PEG-LA-DA) with a nondegradable macromer, poly(ethylene glycol) dimethacrylate (PEGDM). The resulting hydrogels exhibited a range of degradation behavior and mass loss profiles. Chondrocytes were photoencapsulated in gels formulated with 50:50, 25:75, and 15:85 (mol % PEGDM: mol % PEG-LA-DA) and cultured for 6 weeks in vitro. The neocartilaginous tissue formed was examined biochemically and histologically. After 6 weeks, the DNA content in gels with 75 and 85% degradable crosslinks was nearly twice that of the DNA content in the 50% gels. The total collagen content was significantly higher in the 85% gel [2.4 +/- 0.8% wet weight (ww)] compared to the 50% gel (0.22 +/- 0.29% ww). In examining the neocartilaginous tissue with immunohistochemistry, type II collagen was localized in the pericellular region in the 50% gel; however, when increased degradation was incorporated into the gel, type II collagen was found throughout the neotissue. In summary, the important role of hydrogel degradation in controlling and influencing the deposition and distribution of extracellular matrix molecules was demonstrated and quantified.

Animals↗
PubMed1991

Gastric chief cell mass in chronic gastritis. Count and relationships to parietal cell mass and functional indices.

The chief cell mass, expressed as the Zymogenous Index (number of cells per mm2 multiplied by the thickness of the glandular layer) was calculated in 42 subjects with chronic gastritis, and in 40 subjects with normal gastric mucosa, and was compared with the serum concentration of Pepsinogen I (PG I), with the parietal cell mass (expressed as Parietal Index: number of cells per mm2 multiplied by the thickness of the glandular layer), and with the acid output. The results showed that there are no significant variations in the chief cells in comparison with healthy controls in the case of superficial gastritis and follicular gastritis. Conversely, in the case of pre-atrophic and atrophic gastritis there is a significant reduction in the chief cell mass. The serum PG I increases significantly in the case of superficial gastritis as compared with healthy controls, while it is equivalent in the case of follicular gastritis, decreases non-significantly in pre-atrophic gastritis and is significantly reduced in the case of atrophic gastritis. The parietal cell mass shows a behavior equivalent to that of the chief cell mass, and the acid output decreases significantly in the case of pre-atrophic and atrophic gastritis, with no significant variations in the case of superficial and follicular gastritis. On comparing the behavior of the chief cell mass with that of the parietal cell mass, it was noticed that in the most severe stages of chronic gastritis there is a more pronounced reduction of the former than of the latter.

Adult↗
PubMed1990

Mobbing and psychological terror at workplaces.

In recent years, the existence of a significant problem in workplaces has been documented in Sweden and other countries. It involves employees "ganging up" on a target employee and subjecting him or her to psychological harassment. This "mobbing" behavior results in severe psychological and occupational consequences for the victim. This phenomenon is described, its stages and consequences analyzed. An ongoing program of research and intervention that is currently being supported by the Swedish government is then considered.

Humans↗
PubMed1999

Epidemics of violence.

The concept of behavioral contagion implies that certain behaviors may spread through populations in a way analogous to the spread of microbial diseases. If so, mathematical models that are helpful in understanding the spread of infectious diseases may also help to understand the spread of certain behaviors. The objective of this paper was to explore the possibility that the Kermack-McKendrick model of epidemic spread may help to explain the outbreak of riots in crowds. Predictions made by the mathematical model were compared to descriptions of crowd behavior and of police methods for preventing and controlling the outbreak of riots. Many of the predictions made by the model are consistent with published observations about circumstances where riots may occur, and methods useful for controlling them.

Epidemiologic Methods↗
PubMed1997

[Railroad suicides and attempted suicides in Austria 1990-1994. Extending the hypothesis mass media transmission of suicidal behavior].

Suicide on railways (either by being run over by or jumping in front of a train) is one of the "hardest' suicide methods. In Austria, 617 suicides or attempted suicides on railways were registered between 1990 and 1994. This amounts to 5.73% of all suicides committed in this period with women showing a higher percentage than men. In both men and women there was a predominance of younger age groups; the mean age was higher in women than in men (48.0 vs 40.4 years). There was a significant increase in suicides or attempted suicides on railways after a television report on the stress suffered by train drivers concerning possible suicides. Persuading the mass media to treat the subject of "suicide' with reserve and with greater caution, even when not presenting a distinct suicide model, may be of importance in general suicide prevention.

Adolescent↗
PubMed2005

Body mass index, body shape satisfaction, and weight control behaviors among Korean girls.

The present study investigated the relations among Body Mass Index, body shape satisfaction, and weight control behaviors among Korean girls. Subjects were 266 girls (M age= 16.6 yr., SD= .9), recruited from two girls' high schools in Seoul, Korea. Based on Body Mass Index, 73.7% were normal weight, 22.9% were underweight, and 3.4% were overweight. 174 girls (65.4%) indicated that they were currently using any weight control method. Weight control behaviors differed significantly by Body Mass Index category, with girls whose Body Mass Indexes indicating normal weight being more likely to claim they used weight control behaviors. Also, the girls who rated themselves as dissatisfied with their body shape were more likely to report weight control behaviors.

Adolescent↗
PubMed2005

Dissolution and removal of PAHs from a contaminated soil using sunflower oil.

This study reports on the feasibility of remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soils using sunflower oil, an environmentally-friendly solvent. Batch experiments were performed to test the influence of oil/soil ratio on the remediation of PAH contaminated soil, and to test the mass transfer behaviors of PAHs from soil to oil. An empirical model was employed to describe the kinetics of PAH dissolution and to predict equilibrium concentrations of PAHs in oil. PAH containing oil was regenerated using active carbon. Results show that dissolution of PAHs from a Manufactured Gas Plant (MGP) soil at oil/soil ratios of one or two were almost the same. Nearly all PAHs (81-100%) could be removed by sunflower oil dissolution. Mass transfer coefficients for low molecular PAHs namely fluoranthene, phenanthrene and anthracene were one or two orders of magnitude higher than those for high molecular PAHs with 4-6 rings. Ninety milliliters of PAH containing oil could be regenerated by 10 g active carbon in a batch reactor. Such a remediation procedure indicates that sunflower oil is a promising agent for the removal of PAHs from MGP soils. However, further research is required before the method can be used for in situ remediation of contaminated sites.

Biodegradation, Environmental↗
PubMed2002

Using individualism and collectivism to compare cultures--a critique of the validity and measurement of the constructs: comment on Oyserman et al. (2002).

Analyzing national and ethnic differences in individualism and collectivism, D. Oyserman, H. M. Coon, and M. Kemmelmeier (2002) showed that small differences in scales or samples produce markedly divergent results, challenging the validity of these constructs. The author examines the following limitations of research on individualism and collectivism: It treats nations as cultures and culture as a continuous quantitative variable; conflates all kinds of social relations and distinct types of autonomy; ignores contextual specificity in norms and values; measures culture as the personal preferences and behavior reports of individuals; rarely establishes the external validity of the measures used; assumes cultural invariance in the meaning of self-reports and anchoring and interpretation of scales; and reduces culture to explicit, abstract verbal knowledge.

Cognition↗
PubMed2001

Proteomics of glycoproteins based on affinity selection of glycopeptides from tryptic digests.

Identification of glycoproteins in complex mixtures derived from either human blood serum or a cancer cell line was achieved in a process involving the steps of (1) reduction and alkylation, (2) proteolysis of all proteins in the mixture with trypsin, (3) affinity chromatographic selection of the glycopeptides with an immobilized lectin, (4) direct transfer of the glycopeptide fraction to a reversed-phase liquid chromatography (RPLC) column and further fractionation by gradient elution, (5) matrix-assisted laser desorption ionization mass spectrometry of individual fractions collected from the RPLC column, and (6) peptide identification based on a database search. The types of glycoproteins analyzed were; (1) N-type glycoproteins of known primary structure, (2) N-type glycoproteins of unknown structure, and (3) O-type glycoproteins glycosylated with a single N-acetylglucosamine. Identification of peptides from complex mixtures was greatly facilitated by either C-terminal sequencing with a carboxypeptidase mixture or by comparing chromatographic behavior and mass to standards, as in the case of a known protein. In addition, deglycosylation of peptides with N glycosidase F was necessary to identify N-type glycoproteins of unknown structure. The strength of this approach is that it is fast and targets specific molecular species or classes of glycoproteins for identification. The weakness is that it does not discriminate between glycoforms.

Amino Acid Sequence↗
PubMed1990

Molecular mass, biochemical composition, and physicochemical behavior of the infectious form of the scrapie precursor protein monomer.

A highly purified fraction obtained from scrapie (263-K strain)-infected hamsters' brains by an alternative procedure without proteinase K treatment contained a protease-resistant form of the scrapie precursor protein (PrPSc) and infectivity of 9.9 +/- 0.7 log LD50/ml. Polyclonal antibodies produced against hamster scrapie amyloid protein (PrP27-30) and used in a neutralization test diminished infectivity of the PrPSc preparations by 1.6 log after intracerebral inoculation and by 1 log after intraperitoneal inoculation. PrPSc was subjected to size-exclusion HPLC; greater than or equal to 60% of the eluted infectious units were recovered from the peak with an apparent mass of 30.4 +/- 0.6 kDa. Characterization by UV absorption spectra, SDS/PAGE, immunoblots, N-terminal amino acid sequence, and neutral sugar and amino sugar analyses demonstrated homogeneity of the infectious units. The neutral sugar and amino sugar compositional analyses revealed high mannose, glucosamine, fucose, and sialic acid content. This demonstrated an extensive posttranslational modification by the complex type of N-linked glycosylation and glycane core of C-terminal glycolipid of PrPSc. The results correspond to the predicted size, composition, and sequence of PrPSc and indicate that this protein may be the only component of scrapie infectious unit or the infectious form of scrapie precursor.

Amino Acid Sequence↗