The advent of lead-free perovskite materials with favorable toxicity profiles has made them candidates for in vivo and environmental applications. However, their tendency to leach A-site cations raises concerns about toxicity, catalytic efficiency, and slurry properties. The present study investigates the long-term leaching kinetics of BaTiO3 powders over 31 days in aqueous solutions of varying pH levels. Using ICP-MS analysis and a numerical model based on the Unreacted Shrinking Core (USC) principle. The study extends the understanding of BaTiO3 stability beyond previously reported timeframes. The findings highlight the material's long-term stability, with implications for biomedical and environmental applications.

• MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• oxidy chemie   MeSH
• prášky, zásypy, pudry * chemie   MeSH
• roztoky MeSH
• sloučeniny barya * chemie   MeSH
• suspenze chemie   MeSH
• titan * chemie   MeSH
• voda * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• barium titanate(IV) MeSH Prohlížeč
• oxidy MeSH
• prášky, zásypy, pudry * MeSH
• roztoky MeSH
• sloučeniny barya * MeSH
• suspenze MeSH
• titan * MeSH
• voda * MeSH

Barium and strontium are often used as proxies of marine productivity in palaeoceanographic reconstructions of global climate. However, long-searched biological drivers for such correlations remain unknown. Here, we report that taxa within one of the most abundant groups of marine planktonic protists, diplonemids (Euglenozoa), are potent accumulators of intracellular barite (BaSO4), celestite (SrSO4), and strontiobarite (Ba,Sr)SO4. In culture, Namystinia karyoxenos accumulates Ba2+ and Sr2+ 42,000 and 10,000 times higher than the surrounding medium, forming barite and celestite representing 90% of the dry weight, the greatest concentration in biomass known to date. As heterotrophs, diplonemids are not restricted to the photic zone, and they are widespread in the oceans in astonishing abundance and diversity, as their distribution correlates with environmental particulate barite and celestite, prevailing in the mesopelagic zone. We found diplonemid predators, the filter-feeding zooplankton that produces fecal pellets containing the undigested celestite from diplonemids, facilitating its deposition on the seafloor. To the best of our knowledge, evidence for diplonemid biomineralization presents the strongest explanation for the occurrence of particulate barite and celestite in the marine environment. Both structures of the crystals and their variable chemical compositions found in diplonemids fit the properties of environmentally sampled particulate barite and celestite. Finally, we propose that diplonemids, which emerged during the Neoproterozoic era, qualify as impactful players in Ba2+/Sr2+ cycling in the ocean that has possibly contributed to sedimentary rock formation over long geological periods. IMPORTANCE We have identified that diplonemids, an abundant group of marine planktonic protists, accumulate conspicuous amounts of Sr2+ and Ba2+ in the form of intracellular barite and celestite crystals, in concentrations that greatly exceed those of the most efficient Ba/Sr-accumulating organisms known to date. We propose that diplonemids are potential players in Ba2+/Sr2+ cycling in the ocean and have possibly contributed to sedimentary rock formation over long geological periods. These organisms emerged during the Neoproterozoic era (590 to 900 million years ago), prior to known coccolithophore carbonate biomineralization (~200 million years ago). Based on reported data, the distribution of diplonemids in the oceans is correlated with the occurrence of particulate barite and celestite. Finally, diplonemids may provide new insights into the long-questioned biogenic origin of particulate barite and celestite and bring more understanding of the observed spatial-temporal correlation of the minerals with marine productivity used in reconstructions of past global climate.

• Klíčová slova
• Euglenozoa, barite, biocrystallization, biogeochemical cycles, celestite,
• MeSH
• baryum MeSH
• minerály MeSH
• oceány a moře MeSH
• plankton MeSH
• síran barnatý * MeSH
• stroncium * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• oceány a moře MeSH
• Názvy látek
• baryum MeSH
• minerály MeSH
• síran barnatý * MeSH
• stroncium * MeSH

The goal of our study is to design BaTiO3 ferroelectric layers that will cover metal implants and provide improved osseointegration. We synthesized ferroelectric BaTiO3 layers on Pt/fused silica substrates, and we studied their physical and bio-properties. BaTiO3 and Pt layers were prepared using KrF excimer laser ablation at substrate temperature Ts in the range from 200°C to 750°C in vacuum or under oxygen pressure of 10 Pa, 15 Pa, and 20 Pa. The BaTiO3/Pt and Pt layers adhered well to the substrates. BaTiO3 films of crystallite size 60-140 nm were fabricated. Ferroelectric loops were measured and ferroelectricity was also confirmed using Raman scattering measurements. Results of atomic force microscopy topology and the X-ray diffraction structure of the BaTiO3/Pt/fused silica multilayers are presented. The adhesion, viability, growth, and osteogenic differentiation of human osteoblast-like Saos-2 cells were also studied. On days 1, 3, and 7 after seeding, the lowest cell numbers were found on non-ferroelectric BaTiO3, while the values on ferroelectric BaTiO3, on non-annealed and annealed Pt interlayers, and on the control tissue culture polystyrene dishes and microscopic glass slides were similar, and were usually significantly higher than on non-ferroelectric BaTiO3. A similar trend was observed for the intensity of the fluorescence of alkaline phosphatase, a medium-term marker of osteogenic differentiation, and of osteocalcin, a late marker of osteogenic differentiation. At the same time, the cell viability, tested on day 1 after seeding, was very high on all tested samples, reaching 93-99%. Ferroelectric BaTiO3 films deposited on metallic bone implants through a Pt interlayer can therefore markedly improve the osseointegration of these implants in comparison with non-ferroelectric BaTiO3 films.

• Klíčová slova
• BaTiO3, Pulsed laser deposition, biotests, ferroelectricity, implants,
• MeSH
• buněčné linie MeSH
• elektřina MeSH
• kostní náhrady chemie   MeSH
• lasery MeSH
• lidé MeSH
• nanočástice chemie   ultrastruktura   MeSH
• osteoblasty cytologie   MeSH
• osteogeneze MeSH
• oxid křemičitý chemie   MeSH
• platina chemie   MeSH
• protézy a implantáty MeSH
• sloučeniny barya chemie   MeSH
• titan chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• barium titanate(IV) MeSH Prohlížeč
• kostní náhrady MeSH
• oxid křemičitý MeSH
• platina MeSH
• sloučeniny barya MeSH
• titan MeSH

BaTiO3 (BTO) layers were deposited by pulsed laser deposition (PLD) on TiNb, Pt/TiNb, Si (100), and fused silica substrates using various deposition conditions. Polycrystalline BTO with sizes of crystallites in the range from 90nm to 160nm was obtained at elevated substrate temperatures of (600°C-700°C). With increasing deposition temperature above 700°C the formation of unwanted rutile phase prevented the growth of perovskite ferroelectric BTO. Concurrently, with decreasing substrate temperature below 500°C, amorphous films were formed. Post-deposition annealing of the amorphous deposits allowed obtaining perovskite BTO. Using a very thin Pt interlayer between the BTO films and TiNb substrate enabled high-temperature growth of preferentially oriented BTO. Raman spectroscopy and electrical characterization indicated polar ferroelectric behaviour of the BTO films.

• Klíčová slova
• BaTiO(3), Ferroelectricity, Implants, PLD, Thin films, TiNb,
• MeSH
• biokompatibilní materiály chemie   MeSH
• difrakce rentgenového záření MeSH
• elektřina MeSH
• elektrody MeSH
• lasery * MeSH
• mikroskopie elektronová rastrovací MeSH
• niob chemie   MeSH
• oxid křemičitý chemie   MeSH
• protézy a implantáty * MeSH
• Ramanova spektroskopie MeSH
• slitiny chemie   MeSH
• sloučeniny barya chemie   MeSH
• titan chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• barium titanate(IV) MeSH Prohlížeč
• biokompatibilní materiály MeSH
• niob MeSH
• oxid křemičitý MeSH
• slitiny MeSH
• sloučeniny barya MeSH
• titan MeSH

The seminal paper by Zhirnov (1958 Zh. Eksp. Teor. Fiz. 35 1175-80) explained why the structure of domain walls in ferroelectrics and ferromagnets is drastically different. Here we show that the antiparallel ferroelectric walls in rhombohedral ferroelectric BaTiO(3) can be switched between the Ising-like state (typical for ferroelectrics) and a Bloch-like state (unusual for ferroelectric walls but typical for magnetic ones). Phase-field simulations using a Ginzburg-Landau-Devonshire model suggest that this symmetry-breaking transition can be induced by a compressive epitaxial stress. The strain-tunable chiral properties of these domain walls promise a range of novel phenomena in epitaxial ferroelectric thin films.

• MeSH
• chemické modely * MeSH
• magnetické pole MeSH
• mechanický stres MeSH
• molekulární modely * MeSH
• počítačová simulace MeSH
• sloučeniny barya chemie   MeSH
• titan chemie   MeSH
• změna skupenství MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• barium titanate(IV) MeSH Prohlížeč
• sloučeniny barya MeSH
• titan MeSH

Dielectric properties of Eu(0.5)Ba(0.5)TiO(3) ceramics were investigated between 10 and 300 K in the frequency range of 1 MHz-100 THz. Permittivity exhibits a strong peak near the ferroelectric phase transition at 215 K. This is mainly due to softening of the lowest frequency polar phonon revealed in THz and infrared spectra. Dielectric relaxation was observed also below the ferroelectric soft mode frequency in the whole investigated temperature region, but it is probably caused by some defects such as Eu(3 + ) cations or oxygen vacancies. This implies that the ferroelectric phase transition has predominantly a displacive character. Raman scattering spectra revealed a lowering of crystal symmetry in the ferroelectric phase and XRD analysis indicated orthorhombic A2mm symmetry below 215 K. The magnetic measurements performed at various frequencies in the field cooled and field heating regime after cooling in zero magnetic fields excluded spin glass behavior and proved an antiferromagnetic order below 1.9 K in Eu(0.5)Ba(0.5)TiO(3).

• MeSH
• elektrická vodivost MeSH
• europium chemie   MeSH
• keramika chemie   MeSH
• magnetismus * MeSH
• sloučeniny barya chemie   MeSH
• teplota MeSH
• titan chemie   MeSH
• železité sloučeniny chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• europium MeSH
• sloučeniny barya MeSH
• titan MeSH
• titanium dioxide MeSH Prohlížeč
• železité sloučeniny MeSH

The use of Valtrac Ring since 1985 has brought about the ability of easier anastomosis suturing and shortening of the operative treatment. As other methods, also Valtrac ring has its disadvantages. Authors present a case report of a complication previously not described in the literature. A 67 year old patient, after right hemicolectomy with ileotransversoanastomosis with the help of Valtrac due to adenocarcinoma, underwent a control colonoscopy six month after operation. Small polyps in colon sigmoideum, colon descendens and transverse were removed and a tissue stripe with ulceration was found during the examination. The bioptic sample was taken from this stripe. After the application of Fragmine, the patient had a massive enterorhagia, which was not even resolved by adrenaline per colonoscopy. The patient underwent re-resection of ileotrasversoanastomosis. A ring of tissue, created by circular necrosis in the place of seroserous connection of biofragmentile ring of both of the lumens, was found in the tissue sample. Stenosis of the anastomosis, dehiscence, bleeding and fistulation are described in the literature as the most common complications after Valtrac use. The incidence is comparable with complications during anastomosis sutured by hand. We would like to bring this extremely rare complication to the attention to all surgeons and gastroenterologists, who perform endoscopic examinations in patients after this surgical procedure.

• MeSH
• anastomóza chirurgická škodlivé účinky   přístrojové vybavení   MeSH
• ileum chirurgie   MeSH
• kyselina polyglykolová škodlivé účinky   MeSH
• lidé MeSH
• senioři MeSH
• síran barnatý škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• kazuistiky MeSH
• přehledy MeSH
• Názvy látek
• kyselina polyglykolová MeSH
• síran barnatý MeSH
• Valtrac MeSH Prohlížeč

BACKGROUND: In recent years, there has been renewed interest in small bowel imaging using a variety of radiologic or endoscopic techniques. This article gives an overview and comparison of old and new techniques used in small bowel imaging. New imaging methods as computed tomography (CT), CT enteroclysis (CTEc), CT enterography (CTEg), ultrasound (US), contrast-enhanced ultrasound (CEUS), US enteroclysis, US enterography, magnetic resonance imaging (MRI), MR enteroclysis (MREc) and MR enterography (MREg) are compared with the older techniques such as small- bowel follow- through (SBFT), conventional enteroclysis (CE) and endoscopic techniques including push enteroscopy, ezofagogastroduodenoscopy (EGD), sonde enteroscopy, ileocolonoscopy, double-balloon enteroscopy, intraoperative enteroscopy and wireless capsule enteroscopy (WCE). METHODS: Systematic scan of Pubmed, Medline, Ovid, Elsevier search engines was used.. Additional information was found through the bibliographical review of relevant articles. RESULTS: SBFT has only secondary role in small bowel imaging. US is still the method of choice in imaging for pediatric populations. US and CEUS are also accepted as a method of choice especially in inflammatory cases. CE has been replaced by new cross - sectional imaging techniques (CTEc/CTEg or MREc/MREg). CTEc combines the advantages of CT and CE. MREc combines the advantages of MRI and CE. Some authors prefer CTEg or MREg with peroral bowel preparation and they strictly avoid nasojejunal intubation under fluoroscopic control. MREc has better soft tissue contrast, showing it to be more sensitive in detecting mucosal lesions than CTEc in inflammatory diseases. CTEg/MREg are techniques preferred for patients in follow-up of the inflammatory diseases. The radiologic community is not unanimous however about their role in the imaging process. CTEc/MREc as well as CTEg/MREg are superior to endoscopic methods in the investigation of small-bowel tumors. WCE gives unparalleled imaging of the mucosal surface of the small bowel especially in the event of obscure gastrointestinal bleeding and inflammatory diseases. CONCLUSIONS: In a comparison of endoscopic and radiologic approaches, radiologic techniques are less invasive for patients, they take less time to investigate and allow imaging the entire small bowel. Some do not involve radiation exposure (US, MR). Endoscopic methods are more expensive, more invasive, need longer examination time and technical special skills but without radiation exposure. The greatest advantage of some endoscopic methods is the possibility of mucosal biopsy in one step with diagnostic examination (EGD, push enteroscopy, intraoperative enteroscopy, ileocolonoscopy).

• MeSH
• gastrointestinální endoskopie MeSH
• kontrastní látky aplikace a dávkování   MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• počítačová rentgenová tomografie MeSH
• síran barnatý aplikace a dávkování   MeSH
• tenké střevo diagnostické zobrazování   patologie   MeSH
• ultrasonografie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• kontrastní látky MeSH
• síran barnatý MeSH

The piezoelectric properties of tetragonal BaTiO(3) crystals with a very high density of 90 degrees twin domain boundaries are analyzed in the framework of the Ginzburg-Landau-Devonshire theory. Computer simulations predict a considerable enhancement of piezoelectric coefficients for domain thicknesses below 50 nm. This enhancement is much larger than the effect of the domain wall broadening mechanism of Rao and Wang (2007 Appl. Phys. Lett. 90 041915), but it is still a too weak effect to explain the domain density enhancement observed in the experiments of Wada and Tsurumi (2004 Br. Ceram. Trans. 103 93). The phenomenon observed here should nevertheless manifest in materials with nanoscopic domains, such as relaxor ferroelectrics and artificial ferroelectric nanostructures.

• MeSH
• chemické modely * MeSH
• elektrická vodivost MeSH
• nanostruktury chemie   ultrastruktura   MeSH
• nanotechnologie metody   MeSH
• počítačová simulace MeSH
• sloučeniny barya chemie   MeSH
• titan chemie   MeSH
• vibrace MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• barium titanate(IV) MeSH Prohlížeč
• sloučeniny barya MeSH
• titan MeSH

UNLABELLED: Amyloidosis is a rare disease characterized by forming pathological protein deposits - amyloid - in many organs and tissues. This decreases their functionality. The aim of this small study was to determine, whether the radiological picture of the small intestine involvement in amyloidosis is in some sense specific as sometimes described in literature giving rise to high suspicion for the disease in symptomatic patients. MATERIAL AND METHODS: The prospective study comprising seven patients hospitalized in surgical department is presented together with a survey on the disease, its appearance in radiological imaging. All patients underwent abdominal ultrasound (ATL 5000 HDI, 7-12MHz linear probe, no contrast enhancement, supine position), abdominal CT (Somatom Plus, Siemens, single detector, conventional abdominal CT protocol) and enteroclysis (Micropaque suspension 300ml, application rate of 75ml/min, dilution with HP-7000 being 1:1 and HP-7000 solution 2000ml, application rate of 120ml/min.). RESULTS: The amyloid deposits in the small intestine could be visualized in five of seven patients with the disease. Enteroclysis revealed a diffuse slowed down intestinal motility with an obstruction-like picture in all of our seven patients. The intestinal secretion was normal, plicae were getting polyp-like shape in five of them forming so called "thumb printing" picture. CT showed thickening of the intestinal wall due to deposits with poor blood supply and contrast retention in five of seven patients. Ultrasound visualized thickened, hypoechoic nodular plicae and slowed down motility in these five patients. The most striking finding was the pathological deposits in the intestinal wall were highly hypo-vascular. However, this picture is very similar to that of ischemic enteritis. All seven patients had proven amyloid deposits from bioptic specimens. CONCLUSION: The diagnosis of amyloidosis must be supported by bioptic examination as it has no pathognomic radiological picture. Nevertheless, it allows usually to rise a high suspicion for this and sometimes even guess the type of the pathological protein involved. This can start a search for the primary reason of possible amyloidosis and thus perhaps spear the patients quality of life.

• MeSH
• amyloidóza komplikace   diagnóza   MeSH
• dyspepsie etiologie   MeSH
• gastrointestinální intubace metody   MeSH
• kontrastní látky aplikace a dávkování   MeSH
• lidé MeSH
• nemoci střev diagnóza   MeSH
• počítačová rentgenová tomografie MeSH
• prospektivní studie MeSH
• senzitivita a specificita MeSH
• síran barnatý MeSH
• tenké střevo diagnostické zobrazování   MeSH
• ultrasonografie MeSH
• vylepšení obrazu metody   MeSH
• vzácné nemoci MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• Názvy látek
• kontrastní látky MeSH
• síran barnatý MeSH