Physical effects of the respiratory syncytial virus on human cells.

Respiratory syncytial virus is the leading cause of lower respiratory tract infection in infants and currently lacks an effective vaccine or treatment beyond symptom relief. The atomic force microscope is particularly well suited for imaging biological samples including DNA, proteins, cells, and viral activity. Analyzing fixed HEp-2 cells with the AFM after infection and incubation with RSV for periods up to 24 hrs reveals several physical changes that may lead to a better understanding of the viral effects on living cells. Comparing cells fixed with methanol or glutaraldehyde and osmium tetroxide suggests substantial volume losses in the cells regardless of the fixatives used. Suggested mechanisms for the volume decrease include a combination of the creation of an osmotic pressure gradient within the cell and overall cellular collapse. Elastic modulus calculations were performed on the fixed cells at each duration of infection and analyzed for correlations to other physical properties. Hydrophobic interaction forces were also measured and analyzed in order to characterize chemical changes to the cell membrane. It was found that the elastic modulus did not decrease throughout the entire infection for up to 24 hours, but the hydrophobic expression on the cell surface steadily decreased over this same period. This decrease is attributed to the rapid removal and repair of the cell membrane by the RSV virions during exocytosis. Based on this study on methanol fixed cells, it was confirmed that RSV infection does not appear to modify the actin cytoskeleton of human cells

Hemijske karakteristike visoko-krečnjačkih zemljišta koje određuju raspodelu fosfora

Phosphorus fractions from three highly calcareous soils (average, 24.9 +/- 4.8 %CO32-) from sampling sites with a Mediterranean climate were isolated by sequential extraction. In order to provide a more reliable basis for the definition of the obtained P-fractions, principal component analysis was applied and from the chemical characteristics of the 14 investigated soils, those characteristics which define at he content and association features of the P-fractions were assessed. The soils are characterized by a relatively high pH (8.0-8.2) and by significantly differing contents of organic mater, acid-soluble Mg and total P. These differences affected the various association features of the P-fraction with the soil constituents. The NH4F-P fraction (isolated with 0.5 M NH4F, pH 8.2) is defined by the contents of the main metals of the oxide-hydroxide-clay associations (Al, Fe, Mn) or by the the redox potential (Eh) of Mn. The accumulation of NaOH-phosphorus (extractable with 0.1 M NaOH) depended on the constituents of the oxide hydroxide-clay association, the humic substances and Eh-related factors. In those soils in which NaOH-P is defined by the oxide-hydroxide-clay association, the participation of Fe as a bridge-forming metal is proposed. The main part of total P, i.e., Delta P = TP - (NH4F-P + NaOH-P) is defined by the status of Mn- and Fe-humic complexes or by the concentration of hydroxyl-ions.Iz tri visoko-krečnjačka zemljišta (prosečni sadržaj CO 3 2- 24.9 ± 4.8%, pH 8.0 - 8.2), sa lokacija sa sredozemnom klimom, izolovane su frakcije fosfora sekvencijalnom ekstrakcijom. U cilju obezbeđivanja pouzdanije osnove za definisanje dobijenih frakcijafosfora (P-frakcija), primenjena je analiza principalne komponente (PC-analiza). Među 14 hemijskih karakteristika zemljišta, izdvojene su one koje definišu sadržaj pojedinih P-frakcija i prirodu njihove asocijacije sa sastojcima zemljišta. Frakcija NH 4-P (izolovana sa 0,5M NH 4F, pH = 8,2) definisana je sadržajem glavnih metala oksidne-hidroksidne-glinene asocijacije (Al, Fe, Mn) ili Eh-statusom izraženim sadržajem Mn. Akumulacija NaOH-P (ekstrahovanog sa 0,1 M NaOH) zavisila je od sastojaka oksidne-hidroksidne-glinene asocijacije, od huminskih supstanci i od faktora koji stoje u vezi sa Eh. U onim zemljištima u kojima je NaOH-P definisana sastojcima oksidne-hidroksidne-glinene asocijacije, pretpostavljeno je vezivanje fosfora preko Fe-mostova. Glavna količina fosfora ∆P = TP - (NH 4F-P + NaOH-P), u pojedinim zemljištima definisana je ili statusom Mn- i Fe-huminskih kompleksa, ili pH-vrednošću

Analitička primena derivativne spektrofotometrije

1. Introduction 2. Basic characteristics of derivative spectrophotometry 2.1. Increase of spectra resolution 2.2. Elimination of the influence of baseline shift and matrix interferences 2.3. Enhancement of the detectability of minor spectral features 2.4. Precise determination of the positions of absorption maxima 2.5. Signal-to-noise ratio (SNR) 2.6. Quantitative analysis 3. Analytical applications 3.1. Inorganic analysis 3.2. Organic and pharmaceutical analysis 3.3. Analysis of food and water 3.4. Application of derivative spectrophotometry for the determination of equilibrium constants.Razmatrani su osnovni principi derivativne spektrofotometrije (DS) i njene prednosti i ograničenja u odnosu na normalnu spektrofotometriju. Dat je pregled analitičke primene DS u različitim oblastima: neorganskoj i organskoj analizi, analizi farmaceutskih preparata, kliničkoj analizi, analizi hrane, hemije životne sredine, hemijskoj ravnoteži

Inhibition of a Langerhans Cell-Mediated Immune Response by Treatment Modalities Useful in Psoriasis

Neither the pathogenesis of psoriasis nor the mechanism whereby seemingly diverse therapies alter the disease is understood. In this study, several antipsoriatic agents were tested for their effects on the skin cell lymphocyte reaction (SLR), an immunologic assay in which HLA-DR antigens on Langerhans cells (LC) stimulate proliferation of allogeneic lymphocytes. Every agent tested (cortisol, methotrexate, hyperthermia, anthralin) inhibited the SLR at therapeutic dose levels. By contrast, a variety of antibiotics, an anti-inflammatory agent, and lithium carbonate and propranolol, two drugs known to be ineffective in psoriasis, failed to inhibit the SLR. Finally, we have shown that hyperthermia and anthralin treatments are toxic for LC whereas they have little or no effect on keratinocyte viability. These results suggest that antipsoriatic agents may act in psoriasis by alteration or killing of LC

Protolitičke ravnoteže bromazepama

The protolytic equilibria of bromazepam, an ampholyte sparingly soluble in water, in homogeneous and heterogeneous systems were studied in the pH range 0–14 at 25ºC and at ionic strength of 0.1 mol/dm3 (NaCl). On the basis of 13C-NMR spectra, the protonation site was predicted – in acidic media the pyridine nitrogen of bormazepam is protonated. The acidity constants of bromazepam were determined spectrophotometrically (pKa1 2.83 and pKa2 11.60) and potentiometrically (pKa1 2.99). In the heterogeneous system the following equilibrium constants were determined: Ks0 =[HA](pKs0 3.44), Ks1 =[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04).Proučavane su protolitičke ravnoteže bromazepama, amfolita iz klase 1,4-benzodiazepina, slabo rastvornog u vodi. Ispitivanja su vršena u homogenom i heterogenom sistemu u pH intervalu 0–14, na temperaturi 25ºC i pri jonskoj sili 0,1 mol/dm3 (NaCl). Na osnovu 13C-NMR spektara pretpostavljeno je da do protonovanja u molekulu bromazepama dolazi na piridinskom atomu azota. Kiselinske konstante određene su spektrofotometrijski (pKa1 2.83 and pKa2 11.60) i potenciometrijski (pKa1 2,99). U heterogenom sistemu određene su sledeće ravnotežne konstante Ks0 =[HA](pKs0 3.44), Ks1=[H2A+]/[H3O+](pKs1 0.61), and Ks2 =[A-][H3O+](pKs2 15.04)

Protolitičke ravnoteže u homogenom i heterogenom sistemu ketokonazola i njegovo direktno spektrofotometrijsko određivanje u tabletama

The acid-base equilibria of a diprotic, slightly hydrosoluble base ketoconazole were studied in homogeneous and heterogeneous water systems. The determinations were performed at 25ºC at a constant ionic strength of M(NaCl). The acidity constant Ka1 was determined by potentiometric (pKa1 3.20) and spectrophotometric (pKa1 3.26) methods. A pKa2 constant of 6.10 was obtained based on the equilibrium constants pKs0 4.84 and pKs1 -1.26, determined in a heterogeneous ketoconazole system. The obtained values of the constants served to calculate the solubility and the distribution of the equilibrium forms of ketoconazole as a function of pH. On the basis of the distribution of the equilibrium forms of ketoconazole, a spectrophotometric method for the determination of its content in commercial tablets was developed. The determinations were performed at 225 nm in 0.1 M HCl. The method is simple and rapid and enables the direct spectrophotometric determination of the content of ketoconazole without previous isolation.Proučene su kiselinsko-bazne ravnoteže u homogenom i heterogenom vodenom sistemu ketokonazola, diprotične teško rastvorne baze. Određivanja su vršena na temperaturi 25ºC i pri konstantnoj jonskoj sili 0,1M(NaCl). Kiselinska konstantaKa1 određena je potenciometrijski (pKa1 3,20) i spektrofotometrijski (pKa1 3,26). Konstanta pKa2 6,10 izračunata je iz ravnotežnih konstanti određenih u heterogenom sistemu: pKs0 4,84 i pKs1 -1,26. Na osnovu dobijenih vrednosti za konstante izračunata je rastvorljivost i raspodela ravnotežnih oblika ketokonazola u funkciji pH. Na bazi raspodele ravnotežnih oblika ketokonazola predložena je spektrofotometrijska metoda za njegovo određivanje u komercijalnim tabletama. Određivanja su vršena na talasnoj dužini 225 nm u 0,1M HCl.Metoda je jednostavna i brza, i omogućava direktno spektrofotometrijsko određivanje ketokonazola, bez prethodnog izolovanja

Određivanje pKa vrednosti i korelacija sa strukturom p-supstituisanih trans-2,3-epoksi-4-okso-4-fenilbutanskih kiselina

The pKa values for a series of eight p-substituted trans-2,3-epoxy-4-phenyl butanoic acids (p-substituted trans-β-aroylepoxyacrylic acids) have been determined potentiometrically in aqueous media at 25 °C at an ionic strength of 0.1 mol/dm3 (NaCl). The transmission of polar effects from the substituents on the phenyl nucleus to the carboxylic group through the side chain involving a carbonyl group and an epoxide ring was investigated. The pKa values were correlated with structure using the Hammett, Taft and Yukawa-Tsuno approaches. The Hammett ρ constant (0.34) was compared with analogue values for structurally similar acids.Određene su pKa vrednosti za seriju od osam p-supstituisanih trans-2,3-epoksi-4-okso-4-fenilbutanskih kiselina (p-supstituisanih trans-β-aroilepoksiakrilnih kiselina). Vrednosti su određene potenciometrijski u vodenoj sredini na 25 °C i jonskoj sili 0.1 mol/dm3 (NaCl). Proučavan je prenos polarnih efekata sa supstituenata na fenil jezgru ka karboksilnoj grupi kroz bočni niz koji sadrži karbonilnu grupu i epoksidni prsten. pKa vrednosti su korelisane sa strukturom primenom Hammett-ovog, Taft-ovog i Yukawa-Tsuno-ovog pristupa. Hammett-ova ρ konstanta (0,34) je upoređena sa analognim vrednostima za strukturno slične kiseline

An Evaluation of Feminist Authors and Their Critics

The expansion of the feminist movement in literature has significantly impacted society. My interest in the lives and literature of women authors and the resulting opinions of feminist literary critics stems from the struggles endured by these women. Sallie Bingham is an accomplished writer who has not been regularly reviewed by the national media. My research allowed me to formulate a conclusion as to why this remarkable author has received such inconsistent reviews. I am in the process of reading and analyzing several of Ms. Bingham\u27s works including Winter Term, After Such Knowledge, Passion and Prejudice, and Red Car and will continue with a search of corresponding commentaries in order to learn more about this incredible woman and her impact on feminist literature. My mentor, Dr. Sonya Jones, has been engaged in an ongoing correspondence with Ms. Bingham and has had several interviews with her in person, and I anticipate the possibility of conducting an exclusive personal interview with her as well. The second part of my project entailed a systematic documentation of women authors mentioned and critiqued within the New York Review of Books. I cataloged the reviews, documented the number of women authors, and summarized the content and opinion indicated within each review. The results included a comparison between the number of female and male authors and an analysis describing the nature of the reviews for each gender

Spectrophotometric determination of flurazepam in pharmaceutical formulations

Two spectrophotometric methods are proposed for the determination of flurazepam in pharmaceutical formulations. The first one, a very sensitive and fast direct spectrophotometric method is based on the measurement of the absorbance of aqueous flurazepam monohydrochloride solution (pH 6) at the wavelength of maximum absorption at 230 nm. The second one, a difference spectrophotometric method, is based on the measurement of the absorbance difference between equimolar solutions of flurazepam monoprotonated (pH 6) and diprotonated (pH 0) forms at 225 nm. Both methods were applied to the determination of flurazepam in capsules which contain flurazepam monohydrochloride. To extend the application range of both methods, we examined optimum conditions which enable the determination of flurazepam in formulations in form of flurazepam dihydrochloride

A spectrophotometric method for the determination of equilibrium constants of the reversible 1,4-benzodiazepine ring-opening reaction

A general spectrophotometric method is proposed for the quantitative investigation of the hydrolysis of 1,4-benzodiazepines which, under the effect of nucleophilic hydration, undergo reversible cleavage of the 4,5-azomethine bond, followed by simultaneous simple acid-base reactions. The method is based on establishing the pH region of the solution in which, at the state of complete equilibration, three species dominate, as well as on using suitable isosbestic points and the differences in rates of simple protolysis and hydrolysis. The method is presented using flurazepam as an example, but it also can be applied to other compounds which hydrolyse by a similar mechanism