1,728 research outputs found
Partitioning of quinapril anion between cetyltrimethylammonium bromide micelles and water
The interaction of the anion of quinapril (QUIN), angiotensin converting enzyme (ACE) inhibitor, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was studied as a model system for drug/membrane interactions. From the dependence of differential absorbance at λ=272 nm on CTAB concentration, by using mathematical model that treats the solubilization of QUIN anion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant Kb was obtained.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
Nova razmatranja malih složenih magnetskih sustava
In this paper, a composed A + B magnetic system, with spins JA = 2 and JB = 3/2, is considered within the mean-field approximation, in the framework of Tsallis nonextensive statistics. Our motivation is twofold: (1) to approach the existing experimental data of manganese oxides (manganites), where Mn3+ and Mn4+ form two magnetic sublattices, and (2) to investigate the structure of nonextensive density matrices of composed systems. By imposing that thermodynamic quantities, such as the magnetization of sublattices A and B, must be invariant whether the calculation is taken over the total Hilbert space or over partial subspaces, we found that the expression for the nonextensive entropy must be adapted. Our argument is supported by the calculation of sublattice magnetizations MA and MB, internal energy, UA and UB and magnetic specific heat, CA and CB. It is shown that only with the modified entropy, the two methods of calculation agree to each other. Internal energy and magnetization are additive, but no clear relationship was found between SA, SB and the total entropy SA+B for q /= 1. It is shown that the reason for the failure of the standard way of calculation is the assumption of statistical independence between the two subsystems, which however does not affect the density matrix in the full Hilbert space.Razmatramo magnetski sustav složen od sastavnica A i B sa spinovima JA = 2 i JB = 3/2 u približenju srednjeg polja i Tsallisove nesveobuhvatne statistike. Dva su povoda: (1) opisati poznate mjerne podatke za manganove okside (manganite), u kojima Mn3+ i Mn4+ tvore dvije magnetske podrešetke, i (2) istražiti strukturu nesveobuhvatne matrice gustoće složenih sustava. Postavljajući da termodinamičke veličine, kao magnetizacija podrešetaka A i B, moraju biti invarijantne kako za račun u cijelom Hilbertovom prostoru, tako i u pojedinim podrešetkama, nalazimo da se izraz za nesveobuhvatnu entropiju mora primijeniti. Naša tvrdnja se zasniva na računu magnetizacije podrešetaka MA i MB, unutarnje energije UA i UB, i magnetske specifične topline, CA i CB. Pokazuje se da su s izmijenjenom entropijom obje metode u skladu. Unutarnja energija i magnetizacija se pribrajaju, ali između SA, SB i ukupne entropije SA+B nismo našli jednostavan odnos za q /= 1. Pokazuje se da je pretpostavka o neovisnosti dvaju podsustava razlog što uobičajen način računanja entropije nije dobar, što ne utječe na račun matrice gustoće u cijelom Hibertovom prostoru
Nova razmatranja malih složenih magnetskih sustava
In this paper, a composed A + B magnetic system, with spins JA = 2 and JB = 3/2, is considered within the mean-field approximation, in the framework of Tsallis nonextensive statistics. Our motivation is twofold: (1) to approach the existing experimental data of manganese oxides (manganites), where Mn3+ and Mn4+ form two magnetic sublattices, and (2) to investigate the structure of nonextensive density matrices of composed systems. By imposing that thermodynamic quantities, such as the magnetization of sublattices A and B, must be invariant whether the calculation is taken over the total Hilbert space or over partial subspaces, we found that the expression for the nonextensive entropy must be adapted. Our argument is supported by the calculation of sublattice magnetizations MA and MB, internal energy, UA and UB and magnetic specific heat, CA and CB. It is shown that only with the modified entropy, the two methods of calculation agree to each other. Internal energy and magnetization are additive, but no clear relationship was found between SA, SB and the total entropy SA+B for q /= 1. It is shown that the reason for the failure of the standard way of calculation is the assumption of statistical independence between the two subsystems, which however does not affect the density matrix in the full Hilbert space.Razmatramo magnetski sustav složen od sastavnica A i B sa spinovima JA = 2 i JB = 3/2 u približenju srednjeg polja i Tsallisove nesveobuhvatne statistike. Dva su povoda: (1) opisati poznate mjerne podatke za manganove okside (manganite), u kojima Mn3+ i Mn4+ tvore dvije magnetske podrešetke, i (2) istražiti strukturu nesveobuhvatne matrice gustoće složenih sustava. Postavljajući da termodinamičke veličine, kao magnetizacija podrešetaka A i B, moraju biti invarijantne kako za račun u cijelom Hilbertovom prostoru, tako i u pojedinim podrešetkama, nalazimo da se izraz za nesveobuhvatnu entropiju mora primijeniti. Naša tvrdnja se zasniva na računu magnetizacije podrešetaka MA i MB, unutarnje energije UA i UB, i magnetske specifične topline, CA i CB. Pokazuje se da su s izmijenjenom entropijom obje metode u skladu. Unutarnja energija i magnetizacija se pribrajaju, ali između SA, SB i ukupne entropije SA+B nismo našli jednostavan odnos za q /= 1. Pokazuje se da je pretpostavka o neovisnosti dvaju podsustava razlog što uobičajen način računanja entropije nije dobar, što ne utječe na račun matrice gustoće u cijelom Hibertovom prostoru
Weight Changes Post-Phentermine Use
Purpose: Evaluate weight maintenance in subjects who lost weight while taking phentermine (PTM). Methods: This study was conducted by utilizing a validated survey to collect self-reported data about weight changes post-PTM use. The survey was sent to 19,986 email addresses of current and former patients of a PTM-based outpatient clinic, located in Chicago, IL; 546 participants completed the survey. Results were analyzed using a variety of techniques. Results: At the time of the survey, 42% of responders maintained all the weight lost while on PTM, and 25.2% had maintained a weight loss of at least 10% of their body weight. The average weight lost and maintained at the time of the survey was 3.75% ± 13.8% of body weight or 8.74 lbs ± 27.45 lbs. Nineteen responders had no net weight change. Fifty-nine responders reported a net weight gain, ranging from 2 to 70 lbs with a mean net weight gain of 16.07 lbs ± 13.87 lbs. The duration of time since discontinuing PTM use had a significant correlation with weight maintenance: r = 0.340, p value = .000. There was no significant correlation between duration of time using PTM and weight maintenance. No correlations were identified between education, income, or ethnicity and weight maintenance. A correlation was identified between weight maintenance and current exercise level: r = 0.218, p value = .000. Conclusions: Although more research is needed, with the results of this study, the investigators suggest that post-PTM use, weight regain is not significantly higher than weight regain through other weight loss programs. In order to achieve long-term weight loss maintenance, it may behoove patients to receive professional guidance about behavior modifications to maintain weight lost, particularly related to exercise and dietary changes. The investigators of this study suggest greater emphasis on behavior modification in patients taking PTM is indicated
Caracterização de Latossolos com horizontes A Húmico sob diferentes usos na Região Serrana do Rio de Janeiro.
Horizontes com altos teores de carbono e grandes espessuras, são observados em diferentes classes de solos e regiões do Brasil, no entanto, ainda pouco entendida a sua formação e dinâmica na paisagem, bem como a influência do uso com cultivo agrícola. O trabalho teve como objetivo avaliar os atributos químicos, físicos e a composição isotópica do carbono em amostras de Latossolos com horizonte A húmico sob diferentes usos no município de Bom Jardim, RJ. Foram coletadas amostras de solos com horizontes A húmico sob floresta, eucalipto, café, pastagem, olericultura e maracujá. Os solos foram avaliados quanto à morfologia, composição química, física e isotópica do carbono (δ13C). Os horizontes A húmicos apresentam variações nos atributos químicos devido a aplicação de insumos agrícolas. O efeito do uso nos atributos do solo pode ser observado pelos menores teores de C org nos horizontes superficiais sob olericultura, pastagem e maracujá. A amplitude dos valores de δ13C demonstram que a vegetação pretérita e atual apresenta-se com mistura de plantas C3 e C4, mas com predomínio de C3 e as pequenas diferenças nos valores do δ13C entre os usos nos horizontes superficiais evidenciam o poder tamponante da matéria orgânica
Residual enzymatic activity as a prognostic factor in patients with Gaucher disease type 1: Correlation with Zimran and GAUSS-I index and the severity of bone disease
Background: Gaucher disease (GD) is an autosomal recessive disorder produced by mutations in the glucocerebrosidase gene (GBA), causing storage of glucosylceramide in reticuloendothelial cells in multiple organs. Traditionally, the prediction of the phenotype based on the genotype has been reported to be limited.Subjects and Methods: We investigated the correlation between the enzymatic residual activity (ERA) and the phenotype at diagnosis of the disease in 45 GD Spanish patients (44 with type I and 1 with type III GD). The genotype involved two of the following previously expressed proteins: c.517A¿>¿C (T134P), 1%; c.721G¿>¿A (G202R), 17%; c.1090G¿>¿T (G325W), 13.9%; c.1208G¿>¿A (S364N), 4.1%; c.1226A¿>¿G (N370S), 17.8%; c.1246G¿>¿A (G377S), 17.6%; c.1289C¿>¿T (P391L), 8.5%; c.1448T¿>¿C (L444P), 3%; and c.1504C¿>¿T (R463C), 24.5%. Recombinant alleles, deletion of 55¿bp in exon 9 and 84GG mutation were considered as mutations with no residual enzymatic activity.Results: The ERA showed a statistically significant correlation with chitotriosidase (P¿<¿0.001), age (P¿<¿0.001), spleen size (P¿<¿0.001), ‘Zimran’s Severity Score Index’ (P¿<¿0.01) and the ‘Gaucher Disease Severity Score Index—Type I’ (P¿<¿ 0.0001) at diagnosis of the disorder. Previous to any medical intervention, a comparison between the ERA and bone involvement, demonstrated a statistically significant relationship (P¿<¿0.01) between the two variables.Conclusions: This study data allowed us to define a new criterion for prognostic assessment of the disease at diagnosis, called Protein Severity Index, which expresses the theoretical severity of the genotype presented by patients, according to the corresponding ERA
Food Additives in Products for Children Marketed in Brazil
Abstract Studies show children suffer fro m adverse effects to food additives, in both acute and chronic forms. Children are among the biggest consumers of processed products and have more susceptibility to these adverse effects. In Brazil, there are few data about the exposure to food additives. Therefore, the objective of this article is to elaborate a database of food additives present in products for children. Th is database was built fro m August 2010 to October 2010 fro m the nutritional information on products for children, which could be found on the web site of a Brazilian supermarket. The informat ion contained on product labels of all foods commercialized on the site were analysed, and those with some description or image d irected to child ren, as well as products generally consumed by children, were organized in four categories (cereals and cereal products, dairy and meat products, candy and chocolate, beverages). The number of additives present in each product, the percentages of each class of additive present in the different food categories and the presence of artificial dyes in each category were presented in tables. Among the 5882 products commercialized on the web site, excluding alcoholic beverages, 506 (8.60%) p roducts were classified as children p roducts, fro m which 468 products contained information on their ingredients (and additives) and 438 products contained at least one additive in their formulat ion. The most used additives were lecithin (45.30%) and citric acid (22.86%) and artificial dyes allura red (9.83%), tartrazine (6.84%), sunset yellow (5.77%), brilliant blue (5.77%). Future studies could be carried out to evaluate the amount used and the intake of these additives by Brazilian children
Primate drum kit: A system for studying acoustic pattern production by non-human primates using acceleration and strain sensors
The possibility of achieving experimentally controlled, non-vocal acoustic production in non-human primates is a key step to enable the testing of a number of hypotheses on primate behavior and cognition. However, no device or solution is currently available, with the use of sensors in non-human animals being almost exclusively devoted to applications in food industry and animal surveillance. Specifically, no device exists which simultaneously allows: (i) spontaneous production of sound or music by non-human animals via object manipulation, (ii) systematical recording of data sensed from these movements, (iii) the possibility to alter the acoustic feedback properties of the object using remote control. We present two prototypes we developed for application with chimpanzees (Pan troglodytes) which, while fulfilling the aforementioned requirements, allow to arbitrarily associate sounds to physical object movements. The prototypes differ in sensing technology, costs, intended use and construction requirements. One prototype uses four piezoelectric elements embedded between layers of Plexiglas and foam. Strain data is sent to a computer running Python through an Arduino board. A second prototype consists in a modified Wii Remote contained in a gum toy. Acceleration data is sent via Bluetooth to a computer running Max/MSP. We successfully pilot tested the first device with a group of chimpanzees. We foresee using these devices for a range of cognitive experiments. © 2013 by the authors; licensee MDPI, Basel, Switzerland
Characterization of the First Conotoxin from Conus ateralbus, a Vermivorous Cone Snail from the Cabo Verde Archipelago
Conus ateralbus is a cone snail endemic to the west side of the island of Sal, in the Cabo Verde Archipelago off West Africa. We describe the isolation and characterization of the first bioactive peptide from the venom of this species. This 30AA venom peptide is named conotoxin AtVIA (δ-conotoxin-like). An excitatory activity was manifested by the peptide on a majority of mouse lumbar dorsal root ganglion neurons. An analog of AtVIA with conservative changes on three amino acid residues at the C-terminal region was synthesized and this analog produced an identical effect on the mouse neurons. AtVIA has homology with δ-conotoxins from other worm-hunters, which include conserved sequence elements that are shared with δ-conotoxins from fish-hunting Conus. In contrast, there is no comparable sequence similarity with δ-conotoxins from the venoms of molluscivorous Conus species. A rationale for the potential presence of δ-conotoxins, that are potent in vertebrate systems in two different lineages of worm-hunting cone snails, is discussed.This work was supported by grants to BMO from the National Institute of General Medical Science, GM 48677 and GM103362. Partial funding was obtained through a PhD grant to JLBN (SFRH/BD/51477/2011) from the European Regional Development Fund (ERDF) through the COMPETE—Operational Competitiveness Program and from national funds through FCT—Foundation for Science and Technology—under the project FCT Project UID/Multi/04423/ and by the project H2020 RISE project EMERTOX—Emergent Marine Toxins in the North Atlantic and Mediterranean: New Approaches to Assess their Occurrence and Future Scenarios in the Framework of Global Environmental Changes—Grant Agreement No. 778069. The sample collection in Cabo Verde was supported by Fundação Calouste Gulbenkian
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