Guinea pig fetus does not change its presentation during second half of gestation

Objectives: The aims of this paper are: 1. To investigate spontaneous changes in fetal presentation during the second half of gestation in guinea pig fetus, 2. to observe provoked changes of fetal presentation, by passive positioning fetus into an upside-down position and “sitting” position. Eight fetuses from singleton pregnancies were included. Experimental design: Ultrasound examinations (Toshiba Nemio SSA-550A apparatus) were started on the 26th day of gestation (GD). Each fetus was examined 2-3 times in each 5-day interval until the end of gestation. First the spontaneous orientation of fetus was determined by tracking along the longitudinal and transversal axes of the fetus with the ultrasound probe. Then the fetus was brought into a head-down position relative to gravity for 5 minutes. The examination was repeated with the fetus in the head-up position. Results: In the period from the 26th – 30th GD in 7 of 21 observations spontaneous changes of presentation were observed. From the 31st GD all 133 observations were negative regarding spontaneous changes of presentation and situs. The chi-squared test showed that difference in spontaneous changes of presentation and situs before versus after 30th day of gestation had a statistical significance (χ² = 25.16 p 0.05). Fetuses were brought into a head-down and head-up 154 times. In none of these attempts did a fetus change presentation during the five minutes of observation. Conclusion: Guinea pig fetuses do not spontaneously or at provocation change presentation after 30th GD

Grey zones of production. Discussing the technology of tools at the Lojanik quarry in west-central Serbia

Flaked stone artefacts found on the quarry Lojanik in west-central Serbia are good examples of how the function of non-diagnostic pieces could be determined through technological and use-wear analysis. In this study, we present the examples of surface clusters and artefacts from stratigraphic layers. Our attention isfocused on the prevailing category of fragmented raw materials in the initial phase of knapping, preforms, debris, shattered pieces of anthropogenic origin and an immense number of artefacts and geofacts.The study of mines and quarries, as well as distribution of the raw materials that come from the central Balkans is an understudied phenomenon. Flaked stone artefacts found on the outcrops of the Lojanik hilltopisa good example of how we can apply technological, petrological and use-wear analysis on this type of site. Keeping in mind the loose context of the finds, as well as the lack of any datable material, this issue has to be approached with a lot of caution, since the locality itself seems to show human presence during Palaeolithic, Neolithic and Chalcolithic. The main focus of the study was put on the prevailing categories linked to the initial extraction of raw material on the site, as well as initial steps of shaping the raw material into cores. Samples were collected from several outcrops and so-called workshops from two localities of thehilltop: Lojanik 1 and Lojanik 2. The focalpoints of interest are categories that include waste, shatter, technical or shaping flakes. Worked pieces of raw material are now in the central position, and the study of these pieces have opened new grounds for this and similar occurrences -the study of so-called “grey zones”ofproduction

The presence of non-carious lesions in children

Introduction A non-carious lesion (NCL) is the loss of hard dental tissue on the neck, tuberculum and incisal edges of the teeth. Interest in clinical presence and in unclear etiology of these lesions allows for their future prevention and treatment. Objective The aim of the study was to determine presence and clinical characteristics of NCLs and dentine hypersensitivity (DH), as well as their possible risk factors in children, in the population of the city of Novi Sad. Methods A total of 55 subjects were included in the present study, aged between three and 18 years. Each subject completed a structured questionnaire related to the etiological factors, and all teeth of each subject were examined by two independent clinical dentists to determine NCLs and DH. In the case of small children, their parents or guardians filled out the questionnaire. Teeth with NCLs and DH were diagnosed according to the Basic Erosive Wear Examination (BEWE) index and by a blast of air according to Schiff and Hypersensitivity Index. The review was carried out by inspection and probing. Results The data were analyzed by clinical examination and comparison of the answers to the questionnaires. We observed an increased presence of non-caries lesions on primary teeth, compared to permanent teeth, with a statistically significant difference (χ2=3.86, df=1, p=0.04). The changes were observed in 82 teeth, and were most frequent on the canine deciduous teeth (65%) and canine permanent teeth (51%). BEWE index was 10-11% to 92-100% in permanent, and 51-57% in deciduous teeth. Majority of patients with primary teeth (89.36%) did not respond to air stimulus, while most patients with permanent teeth (74.29%) did not react to Schiff Index. In the estimate of sensitivity, the respondents reported hypersensitivity on 6.38% of the deciduous teeth and 22.86% of the permanent teeth. Comparison of etiology factors did not reveal a direct link with the appearance of NCLs. Conclusion Research has shown that despite the lack of subjective symptoms, these lesions have distinct clinical characteristics. The fact that they occur even in deciduous dentition justifies the need for further investigations.Uvod Nekarijesne lezije su gubitak čvrstog zubnog tkiva u predelu vrata, kvržica i incizalnih ivica zuba. Sve veća rasprostranjenost i nejasna etiologija razlozi su za povećano kliničko interesovanje, što može biti značajno u prevenciji i lečenju ovih lezija. Cilj rada Cilj istraživanja je bio da se ustanove učestalost i kliničke odlike nekarijesnih lezija, dentinska preosetljivost na mestu lezija i mogući faktori rizika za nastanak ovih lezija kod dece koja žive na teritoriji Novog Sada. Metode rada Ispitano je 55 dece uzrasta od tri godine do 18 godina. Sami ispitanici ili roditelji, odnosno staratelji, popunjavali su upitnik koji je sadržavao pitanja u vezi s potencijalnim etiološkim faktorima. Zube su ispitanicima pregledala dva nezavisna ispitivača. Zubi sa nekarijesnim lezijama i dentinskom preosetljivošću su dijagnostikovani prema kriterijumu indeksa BEWE (engl. basic erosive wear examination) i vazduhom iz pustera prema kriterijumu Šifovog (Schiff) indeksa i indeksa preosetljivosti.Pregled je vršen inspekcijom i sondiranjem. Rezultati Na osnovu analize podataka dobijenih kliničkim pregledom i poređenjem odgovora iz upitnika, utvrđeno je povećano prisustvo nekarijesnih lezija na mlečnim zubima u odnosu na stalne zube sa statistički značajnom razlikom (χ2=3,86; ss=1; p=0,04). Na 82 zuba je uočena nekarijesna promena. Ove promene su najčešće bile na mlečnim očnjacima (65%) i na stalnim očnjacima (51%). Vrednost indeksa BEWE od 11 do 10 bila je kod stalnih zuba 92-100%, a kod mlečnih 51-57%. Kod 89,36% dece s mlečnim i 74,29% sa stalnim zubima nije bilo reakcije na vazdušnu stimulaciju Šifov indeks). Prema proceni ispitanika, osetljivost se javila kod 6,38% mlečnih i 22,86% stalnih zuba (indeks preosetljivosti). Poređenje etioloških faktora nije dovedeno u direktnu vezu s nastankom nekarijesnih lezija. Zaključak Istraživanje je pokazalo da, bez obzira na nedostatak subjektivnih tegoba, ove lezije imaju izrazitu kliničku sliku. Činjenica a se javljaju još u mlečnoj denticiji govori u prilog potrebi za mnogo detaljnijim istraživanjem

Densification and crystallization behaviour of colloidal cordierite-type gels

Three cordierite-type gels were prepared from an aqueous solution of Mg(NO3)2, a boehmite sol and silica sols of very small particle sizes. The effect of varying the silica particle size on the crystallization and densification behaviour was studied. Phase development was examined by thermal analysis and X-ray diffraction, while the densification behaviour was characterized by measuring the linear shrinkage of pellets. The activation energy of densification by viscous flow was determined using the Franckel model for non-isothermal conditions and a constant heating rate. The results show that spinel crystallizes from the colloidal gels prior to cristobalite, and their reaction gives a-cordierite, which is specific for three-phase gels. Decreasing the silica particles size lowers the cristobalite crystallization temperature and the a-cordierite formation temperature. The activation energy of densification by viscous flow is lower and the densification more efficient, the smaller the silica particles are

Appearance of fetal pain could be associated with maturation of the mesodiencephalic structures

Fetal pain remains a controversial subject both in terms of recognizing its existence and the time-frame within which it appears. This article investigates the hypothesis that pain perception during development is not related to any determined structures of the central nervous system (CNS), on the contrary, the process of perception could be made with any structure satisfying conditions that the perception of pain is the organization, identification and interpretation of sensory information in order to represent and understand the environment. According to this definition, chronic decerebrate and decorticate experimental animals, anencephalic, and hydranencephalic patients demonstrate that the basic, most general, appropriate interaction with the environment can be achieved with a functional mesodiencephalon (brain stem, and diencephalon) as the hierarchically highest structure of the CNS during development. In intact fetuses, this structure shows signs of sufficient maturation starting from the 15th week of gestation. Bearing in mind the dominant role of the reticular formation of the brain stem, which is marked by a wide divergence of afferent information, a sense of pain transmitted through it is diffuse and can dominate the overall perception of the fetus. The threshold for tactile stimuli is lower at earlier stages of gestation. The pain inhibition mechanisms are not sufficiently developed during intrauterine development, which is another factor that leads to increased intensity of pain in the fetus. As a conclusion it could be proposed that the fetus is exposed to rudimentary painful stimuli starting from the 15th gestation week and that it is extremely sensitive to painful stimuli

Functionalization of thermo-acid activated sepiolite by amine-silane and mercapto-silane for chromium(VI) adsorption from aqueous solutions

Chromium(VI) adsorption from aqueous solutions onto thermo-acid activated sepiolite functionalized with (3-mercaptopropyl)trimethoxy-silane and [3-(2-aminoethylamino)propyl]trimethoxy-silane was investigated. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis, nitrogen adsorption-desorption, and determination of the point of zero charge were used to characterize the obtained adsorbents. It has been established that the silanes were successfully grafted on the thermo-acid activated sepiolite surfaces and that the structure of parent material was preserved during the functionalization. The adsorption of Cr(VI) onto functionalized thermo-acid activated sepiolite was tested as a function of initial pH values at 298 K. The amine functionalized thermo-acid activated sepiolite showed a higher adsorption capacity than the mercapto functionalized thermo-acid activated sepiolite at all studied initial pH values, especially at the initial pH 2.Predmet ovog rada je funkcionalizacija termo-kiselinski aktiviranog sepiolita primenom (3-merkaptopropil)trimetoksisilana ili merkapto-silana i [3-(2-aminoetil-amino) propil]trimetoksisilana ili amino-silana, određivanje fizičko-hemijskih svojstava i proučavanje adsorpcije Cr(VI) iz vodenih rastvora na funkcionalizovanim materijalima pri različitim početnim pH vrednostima (2,0, 3,0 i 4,5). Za karakterizaciju funkcionalizovanih adsorbenata korišćene su: rendgenska difrakciona analiza (XRD), infracrvena spektroskopska analiza (FT-IR), termogravimetrijska i diferencijalno-termijska analiza (TG/DTA), skenirajuća elektronska mikroskopija (SEM), dok su adsorpciono-desorpcione izoterme azota korišćene za određivanje specifične površine, zapremine i raspodele veličina pora. Tačka nultog naelektrisanja adsorbenata je određena metodom uravnotežavanja posebnih proba. Rezultati karakterizacije su pokazali da je bolja funkcionalizacija termo-kiselinski aktiviranog sepiolita postignuta primenom amino-silana. Tokom funkcionalizacije organosilanima sačuvana je struktura i vlaknasta morfologija termo-kiselinski aktiviranog sepiolita. Kovalentnim vezivanjem amino-silana za površinu termo-kiselinski aktiviranog sepiolita povećava se bazni karakter površine, dok se u slučaju vezivanja merkapto-silana kiselo-bazna svojstva ne menjaju značajno. Specifična površina, zapremina i prečnici pora amino-silaniziranog uzorka su značajno manji u odnosu na nefunkcionalizovan uzorak, dok su kod merkapto-silaniziranog sepiolita približno isti kao kod polaznog materijala. Kapacitet adsorpcije Cr(VI) amino-silaniziranog adsorbenta je veći od kapaciteta merkapto-silaniziranog uzorka na svim ispitivanim početnim pH vrednostima Cr(VI) rastvora i naročito pri veoma niskoj početnoj pH vrednosti (2,0). Dominantan mehanizam adsorpcije Cr(VI) pri početnoj pH rastvora 2,0 na amino-silaniziranom adsorbentu je elektrostatičko privlačenje između Cr(VI) anjona i protonovanih amino grupa, a pri višim početnim pH rastvora moguće je obrazovanje vodoničnih veza između CrO42- i amino grupa. Adsorpcija Cr(VI) na merkapto-silaniziranom adsorbentu se zasniva na elektrostatičkim interakcijama između Cr(VI) anjona i protonovanih merkapto grupa, kao i redukciji Cr(VI) do Cr3+ merkapto grupama, uz elektro-statičko privlačenje redukcijom nastalih Cr3+ i sulfonatnih grupa dobijenih oksidacijom merkapto grupa

Complex formation equilibria between aluminum(III), gadolinium(III) and yttrium(III) ions and some fluoroquinolone ligands. Potentiometric and spectroscopic study

<div><p>Complex formation equilibria of aluminum(III), gadolinium(III), and yttrium(III) ions with the fluoroquinolone antibacterials moxifloxacin, ofloxacin, fleroxacin, lomefloxacin, levofloxacin, and ciprofloxacin were studied in aqueous solution by potentiometric and spectroscopic methods. The identity and stability of metal–fluoroquinolone complexes were determined by analyzing potentiometric titration curves (310 K, <i>μ</i> = 0.15 M NaCl, pH range = 2–11, <i>C</i>_L/<i>C</i>_M = 1 : 1 to 3 : 1, <i>C</i>_M = 1.0 mM) with the aid of Hyperquad2006 program. The main species formed in the system may be formulated as M_pH_qL_r (p = 1, q = −2 to 2, r = 1–3, L = fluoroquinolone anion, logarithm of overall stability constant, log <i>β</i>_p,q,r = in the range <i>ca.</i> −10 to 45). The stability of complexes is mostly influenced by metal ion properties (ionization potential, ionic radius) indicating partial ionic character of the coordination bond. The complexes were also characterized by spectroscopic measurements: spectrofluorimetry, ¹H-NMR, and ESI-MS. Fluorimetric data were evaluated with the aid of HypSpec2014 and indicated the formation of ML_r (r = 1–3) complexes with cumulative conditional stability constants significantly lower than the thermodynamic ones. NMR and MS data corroborate potentiometrically determined speciation. Calculated plasma mobilizing capacity of the ligands generally follows the order levofloxacin > moxifloxacin > ciprofloxacin at concentration levels of the ligands higher or equal to <i>ca.</i> 10⁻⁴ M.</p></div