74 research outputs found
Structure investigation of dimethyl-aluminium, -gallium and -indium O,OЈ-chelate complexes in solution and the solid state. Molecular structure of five-co-ordinated [Me 2 M( -OC 6 H 4 CO 2 Me-2)] 2 adducts
The reaction of trimethyl-aluminium, -gallium and -indium with an equimolar amount of methyl salicylate, 2-(HO)C 6 H 4 CO 2 Me (Hmesal), gives [Me 2 M(mesal)] n chelate complexes in high yield (where n = 1 or 2, M = Al 1 or Ga 2; n = 2, M = In 3). The resulting compounds have been characterised in solution by NMR and IR spectroscopy as well as by cryoscopic molecular weight determinations in benzene; their molecular structures in the solid state were determined by single-crystal X-ray diffraction techniques. All three compounds are dimeric in the solid state, with five-co-ordinated metal centres. The deformation of the metal centre co-ordination sphere is discussed. In solution compounds 1 and 2 are monomeric, four-co-ordinated chelate complexes while 3 retains its dimeric structure. On the basis of the structural observation resulting from this study and with respect to related compounds the following sequence of the Group 13 metal centre Lewis acidity, in four-co-ordinated diorganometallic O,OЈ-chelate complexes is proposed: In у Al > Ga. The past decade has brought a considerable increase in the number of examples of simple neutral monomeric five-and six-co-ordinated organometallic complexes of the Group 13 metals. 1, 2 The results indicate that the formation of compounds with higher co-ordination numbers is not limited to those containing macrocyclic ligands, and Group 13 organometallic chemistry has considerably broadened beyond the sphere of four-co-ordinated compounds that dominated previously. A large group of [R 2 M(O,X)] 2 -type chelate complexes (M = Al, Ga or In, and O,X = O, OЈ-or O,N-bidentate ligand), where diorganometallic alkoxides form oxygen-bridged dimers consisting of five-co-ordinated metal centres, are known. 3,4 These Group 13 organometallic chelate complexes potentially create interesting possibilities for comparative studies of the reactivity of four-and five-co-ordinated compounds. In a previous paper we discussed the influence of O,OЈ-bidentate ligands on the structure of dialkylaluminium O,OЈ-chelate complexes in solution and in the solid state. 4 Although this group of compounds has a tendency to form [R 2 Al(O,O)] 2 -type adducts with five-coordinated metal centres in the solid state, in solution they exhibit a considerably greater structural variety depending on the nature of the chelating ligand. For instance, we have elucidated the electronic factors determining the rearrangement from the five-co-ordinated adduct to the four-co-ordinated monomeric chelate complex upon dissolution (Scheme 1). 4 Such a rearrangement occurs for compounds with unsaturated O,OЈ-bidentate ligands, where the π interaction of the alkoxide oxygen lone electron pair with the chelate ligand unsaturated bond system considerably weakens the Lewis basicity of the bridging oxygen and simultaneously strengthens the basicity of the chelating oxygen owing to π delocalization. The role played by the nature of the bidentate ligand in related gallium and indium derivatives is less clear, because there are very few examples of structurally well characterised dialkylgallium O,Ochelate complexes 3l-3r and only two examples of related indium compounds. 3s,t In view of this, it is of interest to know whether the factors affecting the structure of dialkylaluminium chelate complexes can be extended to gallium and indium derivatives. In this paper we present the structural investigation of the † E-Mail: [email protected] Group 13 metal (M = Al, Ga or In) diorganometallic chelate complexes with the methyl salicylate anion (an unsaturated O,OЈ-bidentate ligand with a π conjugated system) in solution and in the solid state. Results and Discussion The interaction of Me 3 M (M = Al, Ga or In) with an equimolar amount of methyl salicylate (Hmesal) results in the quantitative evolution of methane and formation of diorganometallic O,OЈ-chelate complexes according to equation (1). We reported previously that the addition of 2 equivalents of Hmesal to Me 3 Al yielded a monomeric five-co-ordinated chelate complex MeAl(mesal) 2 . 2b It should be noted that when similar reactions were attempted under identical conditions with trimethylgallium and trimethylindium, only the products corresponding to a 1 : 1 stoichiometry were obtained. Compounds 1, 2 and 3 are stable as solids or in solution under an inert atmosphere. The resulting compounds have been characterised in solution by NMR and IR spectroscopy and by cryoscopic molecular weight measurements. The molecular structures of 1, 2 and 3 have been determined by X-ray crystallography; selected bond lengths and angles are given in Structure of [Me 2 Al(mesal)] n 1 Th
Riedel's thyroiditis - a case report with genes' expression studies
<p>Abstract</p> <p>Background</p> <p>Genetic background of Riedel's thyroiditis remains unknown. Herein, we describe our results of studies on genes expression levels in Riedel's thyroiditis.</p> <p>Case report and genetic findings</p> <p>We report the case of 48-year old woman with Riedel's thyroiditis who has presented unusual course of disease with non-specific cervical discomfort, though as with no pain and/or no compression symptoms. After surgery, thyroid specimens were quantitatively evaluated, regarding <it>PIK3CA, PIK3CD, PIK3CG, Tg, TGFB1, THRB, COL1, CDKN1C, CDH3 </it>and <it>CACNA2D2 </it>genes expression levels, by real-time PCR in the ABI PRISM<sup>® </sup>7500 Sequence Detection System. Out of 10 above genes, in 2 cases the expression was higher than in respective Controls of unchanged thyroid tissue. In the remaining 8 cases, expression in question became comparable or lower as in Controls.</p> <p>Discussion</p> <p>The association between increased expression levels of <it>PIK3CA </it>and <it>CDH3 </it>genes and Riedel's thyroiditis is not well-defined. However, the increased expression of <it>PIK3CA </it>and <it>CDH3 </it>genes in our case report and in previous studies of other authors on various malignancies may suggest possible molecular relation between Riedel's thyroiditis and certain neoplastic processes, the relation of which requires further genetic evaluation. It is to be stressed that gene expression studies in Riedel's thyroiditis are difficult to perform, mainly due to fibrosis, resulting in scarce thyroid specimens and - in consequence - small amount of genetic material.</p
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Trinuclear Cage-Like Zn(II) Macrocyclic Complexes: Enantiomeric Recognition and Gas Adsorption Properties.
Three zinc(II) ions in combination with two units of enantiopure [3+3] triphenolic Schiff-base macrocycles 1, 2, 3, or 4 form cage-like chiral complexes. The formation of these complexes is accompanied by the enantioselective self-recognition of chiral macrocyclic units. The X-ray crystal structures of these trinuclear complexes show hollow metal-organic molecules. In some crystal forms, these barrel-shaped complexes are arranged in a window-to-window fashion, which results in the formation of 1D channels and a combination of both intrinsic and extrinsic porosity. The microporous nature of the [Zn3 12 ] complex is reflected in its N2 , Ar, H2 , and CO2 adsorption properties. The N2 and Ar adsorption isotherms show pressure-gating behavior, which is without precedent for any noncovalent porous material. A comparison of the structures of the [Zn3 12 ] and [Zn3 32 ] complexes with that of the free macrocycle H3 1 reveals a striking structural similarity. In H3 1, two macrocyclic units are stitched together by hydrogen bonds to form a cage very similar to that formed by two macrocyclic units stitched together by Zn(II) ions. This structural similarity is manifested also by the gas adsorption properties of the free H3 1 macrocycle. Recrystallization of [Zn3 12 ] in the presence of racemic 2-butanol resulted in the enantioselective binding of (S)-2-butanol inside the cage through the coordination to one of the Zn(II) ions.This work was supported by the NCN (NarodoweCentrumNauki, Poland) (grant 2011/03/B/ST5/01060).D.P.and J.L.thank the FNP Program“Mistrz” for financial support, and D.F.-J. thanks the Royal Society for funding through a University Research Fellowship.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/chem.20150347
Trinuclear Cage-Like ZnII Macrocyclic Complexes: Enantiomeric Recognition and Gas Adsorption Properties
Three zinc(II) ions in combination with two units of enantiopure 3+3 triphenolic Schiff base macrocycles 1, 2, 3 or 4 form cage-like chiral complexes. The formation of these complexes is accompanied by the enantioselective self-recognition of chiral macrocyclic units. The X-ray crystal structures of these trinuclear complexes show hollow metal-organic molecules. In some crystal forms, these barrel-shaped complexes are arranged in a window-to-window fashion which results in formation of 1-D channels and combination of intrinsic porosity with extrinsic porosity. The microporous nature of the [Zn312] complex is reflected in its N2, Ar, H2 and CO2 adsorption properties. The N2 and Ar adsorption isotherms showed pressure gating behaviour which is without precedent for any noncovalent porous material. The comparison of the structures of the [Zn312] and [Zn332] complexes with that of the free macrocycle H31 reveals a striking structural similarity. In the latter compound two macrocyclic units stitched together by hydrogen bonds form a cage very similar to that formed by two macrocyclic units stitched together by Zn(II) ions. This structural similarity is manifested also by the gas adsorption properties of the free H31 macrocycle. Recrystallization of [Zn312] in the presence of racemic 2-butanol results in enantioselective binding of the (S)-2-butanol inside the cage via coordination to one of Zn(II) ions.This work was supported by the NCN (NarodoweCentrumNauki, Poland) (grant 2011/03/B/ST5/01060).D.P.and J.L.thank the FNP Program“Mistrz” for financial support, and D.F.-J. thanks the Royal Society for funding through a University Research Fellowship.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/chem.20150347
Single nucleotide polymorphisms of NR3C1 gene and recurrent depressive disorder in population of Poland
Depressive disorder is a disease characterized by disturbances in the hypothalamo–pituitary–adrenal axis. Abnormalities include the increased level of glucocorticoids (GC) and changes in sensitivity to these hormones. The changes are related to glucocorticoid receptors gene (NR3C1) variants. The NR3C1 gene is suggested to be a candidate gene affecting depressive disorder risk and management. The aim of this study was to investigate polymorphisms within the NR3C1 gene and their role in the susceptibility to recurrent depressive disorder (rDD). 181 depressive patients and 149 healthy ethnically matched controls were included in the study. Single nucleotide polymorphisms were assessed using polymerase chain reaction/restriction fragment length polymorphism method. Statistical significance between rDD patients and controls was observed for the allele and genotype frequencies at three loci: BclI, N363S, and ER22/23EK. The presence of C allele, CC, and GC genotype of BclI polymorphism, G allele and GA genotype for N363S and ER22/23EK variants respectively were associated with increased rDD risk. Two haplotypes indicated higher susceptibility for rDD, while haplotype GAG played a protective role with OR(dis) 0.29 [95 % confidence interval (CI) = 0.13–0.64]. Data generated from this study support the earlier results that genetic variants of the NR3C1 gene are associated with rDD and suggest further consideration on the possible involvement of these variants in etiology of the disease
Relation between functional polymorphism of catalase gene (- 262C>T) and recurrent depressive disorder
Abstract BACKGROUND: Numerous studies have provided information indicating the involvement of oxidative stress in the pathophysiology of depressive disorder (DD). The antioxidative system protects against the effects caused by reactive oxygen species (ROS). Catalase (CAT) is one of antioxidative enzymes observed to change their levels in the course of depression. The enzyme decomposes hydrogen peroxide (H 2 O 2 ), whose overproduction is a result of many processes taking place in depression. Therefore, functional polymorphism of the CAT gene can be a candidate marker of the risk of depression. DESIGN: The presented study assessed the correlation between -262C>T polymorphism of the CAT gene, which influences the increase of CAT expression and activity, and the risk of depression development. The study, carried out on a homogeneous group recruited from the Polish population, enrolled 149 healthy subjects and 149 depressive patients. The groups were age-matched. RESULTS: The obtained results indicate no correlation between -262C>T polymorphism of the CAT gene (both with respect to genotype distribution and allele frequency) and the risk of depression. Nevertheless, further studies assessing the correlations between depression and polymorphism of the genes encoding antioxidative enzymes on larger groups of subjects should be undertaken
From a Well-Defined Organozinc Precursor to Diverse Luminescent Coordination Polymers Based on Zn(II)-Quinolinate Building Units Interconnected by Mixed Ligand Systems.
Introduction of photoactive building blocks into mixed-ligand coordination polymers appears to be a promising way to produce new advanced luminescent materials. However, rational design and self-assembly of the multi-component supramolecular systems is challenging from both a conceptual and synthetic perspective. Here, we report exploratory studies that investigate the potential of [Zn(q)2]2[tBuZn(OH)]2 complex (q = deprotonated 8-hydroxyquinoline) as an organozinc precursor as well as a mixed-ligand synthetic strategy for the preparation of new luminescent coordination polymers (CPs). As a result we present three new 2D mixed-ligand Zn(II)-quinolinate coordination polymers which are based on various zinc quinolinate secondary building units interconnected by two different organic linker types, i.e., deprotonated 4,4'-oxybisbenzoic acid (H2obc) as a flexible dicarboxylate linker and/or selected bipyridines (bipy). Remarkably, using the title organozinc precursors in a combination with H2obc and 4,4'-bipyridine, a novel molecular zinc quinolinate building unit, [Zn4(q)6(bipy)2(obc)2], was obtained which self-assembled into a chain-type hydrogen-bonded network. The application of the organometallic precursor allowed for its direct reaction with the selected ligands at ambient temperature, avoiding the use of both solvothermal conditions and additional base reagents. In turn, the reaction involving Zn(NO3)2, as a classical inorganic precursor, in a combination with H2obc and bipy led to a novel 1D coordination polymer [Zn2(q)2(NO3)2(bipy)]. While the presence of H2obc was essential for the formation of this coordination polymer, this ditopic linker was not incorporated into the isolated product, which indicates its templating behavior. The reported compounds were characterized by single-crystal and powder X-ray diffraction, elemental analysis as well as UV-Vis and photoluminescence spectroscopy
Halide Mixing and Phase Segregation in Cs2AgBiX6 (X=Cl, Br, I) Double Perovskites from Cesium-133 Solid-State NMR and Optical Spectroscopy
All-inorganic double perovskites (elpasolites) are a promising potential alternative to lead halide perovskite in optoelectronic applications. While halide mixing is a well-established strategy for band gap tuning, little is known about halide mixing and phase segregation phenomena in double perovskites. Here, we synthesize a wide range of single− and mixed−halide Cs2AgBiX6 (X=Cl, Br, I) double perovskites using mechanosynthesis and probe their atomic-level microstructure using 133Cs solid-state MAS NMR. We show that mixed Cl/Br materials form pure phases for any Cl/Br ratio while Cl/I and Br/I mixing is only possible with-in a narrow range of halide ratios (<3 mol% I) and leads to a complex mixture of products for higher ratios. We characterize the optical properties of the resulting materials and show that halide mixing does not lead to an appreciable tunability of the PL emission. We find that iodide incorporation is particularly pernicious in that it quenches the PL emission intensity and radiative charge carrier lifetimes for iodide ratios as low as 0.3 mol%. Our study shows that sol-id-state NMR, in conjunction with optical spectroscopies, provides a comprehensive understanding of the structure-activity relationships, halide mixing and phase segregation phenomena in Cs2AgBiX6 (X=Cl, Br, I) double perovskites
Practical guidelines for the supplementation of vitamin D and the treatment of deficits in Central Europe — recommended vitamin D intakes in the general population and groups at risk of vitamin D deficiency
Wstęp: Wyniki badań z ostatnich lat dokumentują wiele korzyści wynikających z działania witaminy D na organizm człowieka na wszystkichetapach jego życia. Większość badań epidemiologicznych sugeruje, że niedobór witaminy D jest powszechny wśród mieszkańców EuropyŚrodkowej. Naturalną konsekwencją tej sytuacji jest konieczność ciągłego uświadamiania społeczeństwu oraz środowisku medycznemu,jaką rolę odgrywa witamina D w rozwoju i funkcjonowaniu organizmu ludzkiego.Metody: Na podstawie przeglądu danych literaturowych Polski Zespół Wielodyscyplinarny opracował tezy dotyczące zasad suplementacjiwitaminą D, które przesłano do członków Komitetu Naukowego konferencji „Witamina D — minimum, maksimum, optimum”,19–20 Październik, 2012, Warszawa. W trakcie powyższej konferencji z udziałem 550 delegatów oraz Ekspertów różnych dziedzin medycynyomówiono i przedyskutowano propozycje wytycznych suplementacji witaminą D populacji Europy Środkowej.Wyniki: W efekcie przeprowadzonych dyskusji Zespół Ekspertów opracował wytyczne suplementacji witaminą D dla wszystkich grupwiekowych populacji Europy Środkowej. Określono również kryteria diagnostyczne charakteryzujące stan zaopatrzenia organizmu w witaminę D: deficyt witaminy D ustalono jako stężenie 25(OH)D < 20 ng/mL (< 50 nmol/L)], suboptymalne zaopatrzenie jako stężenie25(OH)D wynoszące 20–30 ng/mL (50–75 nmol/L), a stężenie 30–50 ng/mL (75–125 nmol/L) uznano za docelowe dla zapewnienia efektuplejotropowego witaminy D.Wnioski: Poprawa obecnego stanu zaopatrzenia witaminy D w grupach dzieci, młodzieży, osób aktywnych zawodowo i seniorówpowinna zostać włączona do priorytetów polityki zdrowotnej społeczeństw Europy Środkowej.Introduction: Adequate Vitamin D intake and its concentration in serum are important for bone health and calcium–phosphate metabolismas well as for optimal function of many organs and tissues. Documented trends in lifestyle, nutritional habits and physical activityappear to be associated with moderate or severe Vitamin D deficits resulting in health problems. Most epidemiological studies suggest thatVitamin D deficiency is prevalent among Central European populations. Concern about this problem led to the organising of a conferencefocused on overcoming Vitamin D deficiency.Methods: After reviewing the epidemiological evidence and relevant literature, a Polish multidisciplinary group formulated theses onrecommendations for Vitamin D screening and supplementation in the general population. These theses were subsequently sent to ScientificCommittee members of the ‘Vitamin D — minimum, maximum, optimum’ conference for evaluation based on a ten-point scale.With 550 international attendees, the meeting ‘Vitamin D — minimum, maximum, optimum’ was held on October 19–20, 2012 in Warsaw(Poland). Most recent scientific evidence of both skeletal and non-skeletal effects of Vitamin D as well as the results of panellists’ votingwere reviewed and discussed during eight plenary sessions and two workshops.Results: Based on many polemical discussions, including post-conference networking, the key opinion leaders established ranges ofserum 25-hydroxyVitamin D concentration indicating Vitamin D deficiency [< 20 ng/mL (< 50 nmol/L)], suboptimal status [20–30 ng/mL(50–75 nmol/L)], and target concentration for optimal Vitamin D effects [30–50 ng/mL (75–125 nmol/L)]. General practical guidelines regardingsupplementation and updated recommendations for prophylactic Vitamin D intakes in Central European neonates, infants, childrenand adolescents as well as in adults (including recommendations for pregnant and breastfeeding women and the elderly) were developed.Conclusions: Improving the Vitamin D status of children, adolescents, adults and the elderly must be included in the priorities of physicians,healthcare professionals and healthcare regulating bodies. The present paper offers elaborated consensus on supplementationguidance and population strategies for Vitamin D in Central Europe
Colorectal neuroendocrine neoplasms — management guidelines (recommended by the Polish Network of Neuroendocrine Tumours)
Nowotwory/guzy neuroendokrynne (NEN/NET) jelita grubego są rozpoznawane coraz częściej, szczególnie guzy odbytnicy. To zjawisko jest najprawdopodobniej związane z powszechnym wykonywaniem kolonoskopii przesiewowych. Coraz więcej przemawia za tym, że NEN odbytnicy i okrężnicy to dwie odrębne choroby. Nowotwory neuroendokrynne odbytnicy są najczęściej zmianami niewielkich rozmiarów, cechują się niskim lub umiarkowanym stopniem złośliwości histologicznej, dobrym rokowaniem i większość z nich kwalifikuje się do leczenia endoskopowego. Natomiast NEN okrężnicy to często nowotwory agresywne, niskozróżnicowane, o złej lub niepewnej prognozie, wymagające operacji. Zasady postępowania z tymi chorymi stale się zmieniają. Opierając się na najnowszym piśmiennictwie oraz ustaleniach wypracowanych na spotkaniu roboczym Polskiej Sieci Guzów Neuroendokrynnych (grudzień 2016 r.) w pracy uzupełniono i uaktualniono dane i wytyczne postępowania dotyczące NEN jelita grubego, opublikowane w Endokrynologii Polskiej 2013; 64: 494–504.Neuroendocrine neoplasms/tumours (NENs/NETs) of the large intestine are detected increasingly often, especially rectal tumours, which is probably associated with the widespread use of screening colonoscopy. There is a growing body of evidence supporting the thesis that the NENs of the rectum and the NENs of the colon are two different diseases. Rectal NENs are usually small lesions, of low to moderate histological malignancy, associated with good prognosis, and most may be treated endoscopically. NENs of the colon, however, are often aggressive, poorly differentiated, associated with a poor or uncertain prognosis, and require surgical treatment. The management guidelines regarding these groups of patients are constantly changing. On the basis of the recent literature data and conclusions reached by the working meeting of the Polish Network of Neuroendocrine Tumours (December 2016), this study completes and updates the data and management guidelines regarding colorectal NENs published in Endokrynologia Polska 2013; 64: 358–368.
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