Consequences of cooperativity in supramolecular polymers

N,N',N"-Trialkylbenzene-1,3,5-tricarboxamides (BTAs) self-assemble by means of strong, threefold intermolecular hydrogen bonding into well-defined, helical, one-dimensional columnar aggregates.1 When a stereogenic centre is introduced into the alkyl side chains of these BTA molecules, strong Cotton effects are observed in dilute apolar solutions, indicating the preference for one helical conformation over the other.2 A helical sense preference can also be created by the introduction of isotope chirality into the a-position of the alkyl side chains in BTA molecules. Quantitative analysis on the observed process in dodecane demonstrates that a stereoselectively deuterated BTA forms right- (P) and left-handed (M) helical supramolecular polymers with a slight difference in stability upon cooling and the diastereomeric excess (d.e. = ([M]-[P])/([M]+[P])) is 38% at room temperature3. The subtle character of these deuterated-BTA-based supramolecular polymers makes it a highly sensitive probe to investigate the effect of the molecular structure of the alkane solvent in the self-assembly processes4. Furthermore, the effect of adding a racemization reaction into a self-assembly process by using a BTA molecule with a labile stereocenter was investigated. Racemization reaction in a self-assembling BTA system follows nonfirst-order reaction kinetics. Enantioenriched BTA molecules are obtained from a racemizing solution in the presence of a sergeant molecule which is unreactive towards base. The results are further analyzed by using a theoretical model which is capable of precise quantitative description of the experimental data obtained. The calculations are fully confirmed by experimental data with even the smallest details being fully explained by the methodology employed4. This dissertation focuses on the self-assembly process of BTA molecules and investigates the effect of isotope substitution, alkane solvent employed for self-assembly process and the introduction of racemization reaction into the self-assembly process. 1. A. R. A. Palmans, E. W. Meijer, Angew. Chem. Int. Ed. 2007, 46, 8948. 2. P. J. M. Stals, M. M. J. Smulders, R. Martin-Rapùn, A. R. A. Palmans, E. W. Meijer, Chem. Eur. J. 2009, 15, 2071. 3. S. Cantekin, D. W. R. Balkenende, M. M. J. Smulders, A. R. A. Palmans, E. W. Meijer, Nat. Chem. 2011, 3, 42. 4. S. Cantekin, Y. Nakano, J. C. Everts, P. van der Schoot, E. W. Meijer, A. R. A. Palmans, Chem. Commun. 2012, 48, 3803. 5. S. Cantekin, H. M. M. ten Eikelder, A. J. Markvoort, M. A. J. Veld, P. A. Korevaar, M. M. Green, A. R. A. Palmans and E. W. Meijer, Angew. Chem. Int. Ed. 2012 DOI 10.1002/anie.201201701

Antimicrobial therapy for otitis media with effusion ( secretory otitis media)

Objective. —To determine the effectiveness of antimicrobial treatment for otitis media with effusion ( secretory otitis media) in children. Data Source. —We report the reexamination of a previously published study by Mandel et al that evaluated the efficacy of a 2-week course of antimicrobials (amoxicillin trihydrate) with and without a 4-week course of an oral decongestant-antihistamine combination in a double-blind, placebo-controlled, randomized trial involving 518 infants and children with otitis media with effusion. Data Synthesis. —At 4 weeks, amoxicillin efficacy as determined by a tympanometric criterion (P=.121) or by a measure of improvement in hearing (P=.311) was insignificant. Only by otoscopic judgment, which is shown to contain a systematic bias as used in this clinical trial, could an argument be made for a marginal efficacy of amoxicillin at the 4-week end point. Logistic regression analyses of the combined effects of treatment and prognostic factors showed no significant differences between placebo- and antibiotic-treated groups for unilateral effusions and for bilateral effusions. When subjects with unilateral and bilateral effusions were combined, the estimated efficacy of antibiotic treatment was 12.3% by otoscopy (P =.014) and 4.8% by tympanometry (P =.171). We also demonstrate the sensitivity of outcome to diagnostic measures used and provide statistical evidence questioning the validity of otoscopic observations in this study. Six weeks after the termination of amoxicillin therapy, the recurrence of effusion was two to six times higher in the amoxicillin-treated children than in those treated with placebo (P=.001), and resolution of effusion was not significantly different among antibiotic and placebo groups (13.6% and 11.3%, respectively; P=.477). Conclusions. —Amoxicillin with and without decongestant-antihistamine combination is not effective for the treatment of persistent asymptomatic middle-ear effusions in infants and children

Morphological variability and age structure in a population of Bufo verrucosissimus (Anura: Bufonidae) from Artvin, Turkey

Morphological variability and age structure in a population of Bufo verrucosissimus (Anura: Bufonidae) from Artvin, Turkey. We investigated morphological diversity (external body traits, coloration patterns and skin structure) and age structure in a population of Caucasian toad (Bufo verrucosissimus) from Lake Bor??ka Karag??l, situated in the vicinity of Artvin on the northeastern border of Turkey and Georgia. Age was determined using phalangeal skeletochronology. The external morphological variability was assessed using the linear measurement of 27 body-related characters and the photographs of each specimen. According to the results, the means of head length and head width were found significantly lower in-arag??l population as opposed to Caucasian populations, but average body size did not differ among all populations. Coloration and pattern features of the specimens from Karag??l were identical to those of Caucasia. Most of the females have brown tones and males are usually olive green and brown. The indiscrete elongated dark bands on parotoids did not extend behind the gland. 2C# analysis confirmed a clear separation between the sexes and a high degree of female-biased sexual size dimorphism was determined based on the body size (SDI index: +0.41). The constructed Von Bertalanffy growth curve models yielded similar profiles in both sexes. Body size and age were significantly correlated in both models, but growth coefficient value was higher in males. Accordingly, the mean age of the Karag??l population is greater in both sexes, but the lifespan and maximum age are greater in Caucasus populations

Identification of the mandibular landmarks in a pediatric population

Objectives: The aim of this study was to determine and compare the reliability to accomplish of common man - dibular landmarks and to determine the incidence of incisive canals, anterior looping, and lingual foramina in children from panoramic and CBCT images. Study Design: Panoramic and CBCT images from 100 children and adolescent patients were randomly selected. In order to grade the visibility of mandibular anatomical landmarks, a four-point rating scale was used. Results: In panoramic images, the mandibular canal could be observed in 92.5% of cases, with good visibility in 12.0%. The mental foramen could be observed in 44.5% of cases, while none had good visibility. Anterior looping of the mental nerve was present in 16.5% of the cases, and none had good visibility. An incisive canal could be identified in 22.5% of cases, with only 1.5% showing good visibility. The lingual foramen could be visualized in 61.0% of cases, with good visibility in 6%. In CBCT images, the mandibular canal, the mental foramen, and the lingual foramen could be observed in 100% of the cases, with good visibility in 51.0%, 98.5%, and 45.0% of cases, respectively. Anterior looping of the mental nerve was present in 26% of cases, with 2% having good visibility. An incisive canal could be identified in 49.5% of cases, with only 75% showing good visibility. Conclusions: This study confirms the applicability of CBCT images to visualize critical structures in children

Orofacial Clefts: Prenatal Diagnosis and Postnatal Management

Orofacial clefts are among the most common congenital malformations which have significant consequences in terms of long term morbidity and health care costs. The overall prevalence of orofacial clefts is estimated to be 9.92 per 10000 births. This review outlines some aspects of etiopathogenesis, prenatal diagnosis and management of the condition

Eyleme Dökme: İntihar Girişiminde Bulunan Bireylerin Deneyimlerinin İncelenmesi Üzerine Nitel Bir Araştırma

Bu araştırmanın amacı intihar girişiminde bulunan bireylerin bu süreci nasıl deneyimlediklerini anlamaya çalışmaktır. Bu amaçla son iki sene içerisinde intihar girişiminde bulunmuş, üniversite öğrencisi olan dört katılımcıyla yarı-yapılandırılmış görüşmeler gerçekleştirilmiştir. Görüşmelerde katılımcılar için intihar davranışının anlamına, süreçteki intihar düşüncelerine ve bu sürece dair yorumlamalarına odaklanılmıştır. Görüşmelerin analizi, bireyin deneyimini derinlemesine keşfetmeyi ve bu deneyime nasıl anlamlar yüklediğini anlamayı amaçlayan Yorumlayıcı Fenomenolojik Analiz yöntemi ile yapılmıştır. Analizler sonucunda dört tema elde edilmiştir: “Mesaj vermek”, “Yakın Birinin Eksikliği”, “Kontrol kaybı” ve “Anne karşı olumsuz duygular”. Temalar, Lacanyen psikanaliz yaklaşımı çerçevesinde tartışılmış ve bütün temalar, Başka ile ilişkilenme sonucunda eyleme dökme üzerinden açıklanmıştır. Katılımcıların Başka’ya olan mesajlarını simgesel düzen içerisinde iletmekte yani dile dökmekte başarısız oldukları düşünülmüştür. Bu anlamda, simgesel düzen içerisinde Başka’nın kendisine sağır olduğunu düşünen özne mesajını eylemleri üzerinden Başka’ya iletmeye çalışmıştır.Publisher's Versio

Prevalence and distribution of staphylococcal enterotoxin genes among Staphylococcus aureus isolates from chicken and turkey carcasses in Algeria

This study is aimed to determine the prevalence of staphylococcus aureus (S.aureus) by biochemical tests in poultry carcasses. It is also intend to detect the distribution of genes for classical staphylococcal enterotoxins A, B, C, D and E (sea, seb, sec, sed and see) and for gene femA, specific for S. aureus species, using multiplex PCR. A total of 385 samples of neck skins from fresh poultry carcasses were collected during the period 2012-2013 from 16 different slaughterhouses located in the region of Algiers, Algeria. The overall prevalence of S.aureus in freshly slaughtered poultry carcasses was 41.56%, with an individual prevalence of 40.63% and 45.71% for chicken and turkey respectively. From the 95 strains of S.aureus identified by biochemical tests. 82 (86.32%) isolates were femA positive using multiplex PCR. The investigation has also revealed the presence of both enterotoxins B and D, with a predominance of seb (13.33%) followed by sed (1.67%), in the chicken carcasses while in turkey only sed was detected (4.55%) It has been found that strains of S.aureus of poultry origin can be enterotoxigenic with the predominance of genes encoding for enterotoxins seb in chicken and sed in turkey. As enterotoxins can be produced in adequate amounts to induce foodborne illnesses, these potential dangers must be considered in terms of a real risk to public health

Istraživanje prisutnosti proizvodnje sluzi, VanA gena i gena za rezistenciju na antiseptike u stafilokoka izoliranih iz goveđeg mastitisa u Alžiru

Staphylococcus strains are frequently associated with clinical and subclinical bovine intra-mammary infection. The virulence factors of staphylococcus have not been widely studied in Algeria. The objective of this study was to determine the frequency of slime production, VanA gene and antiseptic resistance genes in staphylococci strains isolated from bovine mastitis in Algeria. The study examined 35 Staphylococci strains obtained from the inflammatory secretion of mammary glands of cows with mastitis. Slime production was determined by detecting the icaA and icaD genes using the polymerase chain reaction (PCR) method and Congo red agar (CRA) method. The presence of qacAB and qac C antiseptic resistance genes and the VanA resistance gene in these isolates was investigated by PCR. The results of the current study revealed that of the 35 Staphylococci isolates, 42.85% (15/35) and 17.14% (6/35) of the isolates harboured the slime production gene by analysing icaA and icaD genes, respectively and 71.42% (25/35) by the CRA method. However, VanA and antiseptic resistance genes (qacAB and qac C) were not detected in any of the isolates. Therefore, the majority of Staphylococcus strains were capable of producing slime, and the CRA detection rate was higher than the PCR method for the biofilm-producing capacity of Staphylococcus strains. Thus, the presence of the ica genes in Staphylococcus strains confirms its role as a virulence factor in the pathogenesis of bovine mastitis.Sojevi stafilokoka često su povezani s kliničkim i supkliničkim intramamarnim infekcijama goveda. Faktori virulencije stafilokoka nisu dobro istraženi u Alžiru. Cilj ove studije bio je odrediti učestalost proizvodnje sluzi, VanA gena i gena za rezistenciju na antiseptike u sojevima stafilokoka izoliranih iz goveđeg mastitisa u Alžiru. Istraživanja su obuhvatila 35 soja stafilokoka dobivenih iz upalnog sekreta mliječnih žlijezda krava s mastitisom. Proizvodnja sluzi ustvrđena je metodom lančane reakcije polimeraze (PCR) istraživanjem ıcaA i ıcaD gena, odnosno metodom s Kongo crvenim agarom (CRA). Prisutnost qacAB i qac C gena za rezistenciju na antiseptike i VanA gena za rezistenciju u tim izolatima ispitana je pomoću PCR. Rezultati ove studije otkrili su da je od 35 izolata stafilokoka, 42,85 % (15/35) i 17,4 % (6/35) sadržavalo gen za proizvodnju sluzi putem analize ıcaA i ıcaD gena, odnosno 71,42 % (25/35) CRA metodom. Međutim, VanA i geni za rezistenciju na antiseptike (qacAB i qac C) nisu detektirani niti u jednom izolatu. Stoga se iz podataka može zaključiti da je većina sojeva stafilokoka bila sposobna proizvoditi sluz, a detekcija CRA metodom je bila više od PCR metode za kapacitet proizvodnje biofilma sojeva stafilokoka. Stoga, prisutnost ica u sojevima stafilokoka potvrđuje njegovu ulogu kao faktora virulentnosti u patogenezi goveđeg mastitisa

Prevalence and distribuion of staphylococcal enterotoxin genes among Staphylococcus aureus isolates from chicken and turkey carcasses in Algeria

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThis study is aimed to determine the prevalence of staphylococcus aureus (S.aureus) by biochemical tests in poultry carcasses. It is also intend to detect the distribution of genes for classical staphylococcal enterotoxins A, B, C, D and E (sea, seb, sec, sed and see) and for gene femA, specific for S.aureus species, using multiplex PCR. A total of 385 samples of neck skins from fresh poultry carcasses were collected during the period 2012-2013 from 16 different slaughterhouses located in the region of Algiers, Algeria. The overall prevalence of S.aureus in freshly slaughtered poultry carcasses was 41.56%, with an individual prevalence of 40.63% and 45.71% for chicken and turkey respectively. From the 95 strains of S.aureus identified by biochemical tests, 82 (86.32%) isolates were femA positive using multiplex PCR. The investigation has also revealed the presence of both enterotoxins B and D, with a predominance of seb (13.33%) followed by sed (1.67%), in the chicken carcasses while in turkey only sed was detected (4.55%) It has been found that strains of S.aureus of poultry origin can be enterotoxigenic with the predominance of genes encoding for enterotoxins seb in chicken and sed in turkey. As enterotoxins can be produced in adequate amounts to induce foodborne illnesses, these potential dangers must be considered in terms of a real risk to public health

LiFE Assessment Tool

As part of an ongoing study to construct a molecular Turing machine in which a polymer chain is encoded via allosteric information transfer between macrocyclic complexes, we describe the thermodynamic and kinetic characterization of a multicomponent self-assembled system based on a zinc porphyrin macrocyclic compound, a bidentate ligand (1,4-diazabicyclo[2.2.2]octane, DABCO), and a viologen-substituted polymer guest. Initial addition of DABCO to the porphyrin macrocycle in chloroform solution leads to the formation of a stable 2:1 (porphyrin:DABCO) dimeric complex, even under dilute conditions, by means of strong cooperative interactions involving hydrogen and metal-ligand bonds. Further titration of the porphyrin-DABCO mixtures with the polymer gives rise to a complex array of species in the solution. The system is analyzed in detail by a combination of spectroscopic measurements and computational modeling. Each association constant in the binding scheme and the fraction of each individual complex that is formed in solution are determined precisely using a mass-balance model. Kinetic studies revealed that the rates of the polymer threading and dethreading in and out of the dimeric system are remarkably slow, indicating that the polymer is locked inside the cavity of the stable 2:1 dimeric complex as a result of strong allosteric interactions