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1.
Analyst ; 148(23): 5942-5948, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37853759

RESUMO

On the basis of the "seeing is believing" concept and the existing theory of Hg2+ coordination chemistry, for the first time, we innovatively designed and synthesized a visual-volumetric sensor platform with fluorescein and uracil functionalized polyacrylamide hydrogel. Without the aid of any complicated instruments and power sources, the sensor-enabled quantitative µM-level Hg2+ detection Hg2+ by reading graduation on a pipette with the naked eye. The sensor undergoes volumetric response and shows a wide linear response range to Hg2+ (1.0 × 10-6-5.0 × 10-5 mol L-1) with 2.8 × 10-7 mol L-1 as the detection limit. The highly selective (easily distinguished Hg2+ from other common metal ions), rapid response (∼30 min), and acceptable repeatability (RSD < 5% in all cases) demonstrated that the developed sensor is suitable for onsite practical use for the determination of Hg2+ while being low-cost, simple, and portable. The design principles of the obtained materials and the construction techniques and methods of the sensors described in our study provide a new idea for the research and development of smart materials and a series of visual-volumetric sensors for other analytes.

2.
BMC Med Educ ; 23(1): 574, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37582729

RESUMO

BACKGROUND: Simulation-based medical education (SBME) and three-dimensional printed (3DP) models are increasingly used in continuing medical education and clinical training. However, our understanding of their role and value in improving trainees' understanding of the anatomical and surgical procedures associated with liver surgery remains limited. Furthermore, gender bias is also a potential factor in the evaluation of medical education. Therefore, the aim of this study was to evaluate the educational benefits trainees receive from the use of novel 3DP liver models while considering trainees' experience and gender. METHODS: Full-sized 3DP liver models were developed and printed using transparent material based on anonymous CT scans. We used printed 3D models and conventional 2D CT scans of the liver to investigate thirty trainees with various levels of experience and different genders in the context of both small group teaching and formative assessment. We adopted a mixed methods approach involving both questionnaires and focus groups to collect the views of different trainees and monitors to assess trainees' educational benefits and perceptions after progressing through different training programs. We used Objective Structured Clinical Examination (OSCE) and Likert scales to support thematic analysis of the responses to the questionnaires by trainees and monitors, respectively. Descriptive analyses were conducted using SPSS statistical software version 21.0. RESULTS: Overall, a 3DP model of the liver is of great significance for improving trainees' understanding of surgical procedures and cooperation during operation. After viewing the personalized full-sized 3DP liver model, all trainees at the various levels exhibited significant improvements in their understanding of the key points of surgery (p < 0.05), especially regarding the planned surgical procedure and key details of the surgical procedures. More importantly, the trainees exhibited higher levels of satisfaction and self-confidence during the operation regardless of gender. However, with regard to gender, the results showed that the improvement of male trainees after training with the 3DP liver model was more significant than that of female trainees in understanding and cooperation during the surgical procedure, while no such trend was found with regard to their understanding of the base knowledge. CONCLUSION: Trainees and monitors agreed that the use of 3DP liver models was acceptable. The improvement of the learning effect for practical skills and theoretical understanding after training with the 3DP liver models was significant. This study also indicated that training with personalized 3DP liver models can improve all trainees' presurgical understanding of liver tumours and surgery and males show more advantage in understanding and cooperation during the surgical procedure as compared to females. Full-sized realistic 3DP models of the liver are an effective auxiliary teaching tool for SBME teaching in Chinese continuing medical education.


Assuntos
Neoplasias , Sexismo , Humanos , Feminino , Masculino , Fígado/diagnóstico por imagem , Fígado/cirurgia , Abdome , Impressão Tridimensional
3.
Appl Microbiol Biotechnol ; 103(15): 6169-6186, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31165225

RESUMO

Ulcerative colitis (UC) is a chronic relapsing disease. Treatment of UC would benefit from specific targeting of therapeutics to the intestine. Previous studies have demonstrated that bovine lactoferricin and lactoferrampin have bactericidal, anti-inflammatory, and immunomodulatory effects. Here, we investigated whether oral administration of a bovine lactoferricin-lactoferrampin (LFCA)-encoding Lactococcus lactis (LL-LFCA) strain could alleviate experimental colitis. LFCA derived from LL-LFCA inhibited the growth of Escherichia coli and Staphylococcus aureus in vitro. In mice, administration of LL-LFCA decreased the disease activity index and attenuated dextran sulfate sodium (DSS)-induced body weight loss and colon shortening. LL-LFCA treatment also ameliorated DSS-induced colon damage, inhibited inflammatory cell infiltration, significantly decreased myeloperoxidase activity, and ameliorated DSS-induced disruption of intestinal permeability and tight junctions. In addition, 16S rDNA sequencing showed that LL-LFCA reversed DSS-induced gut dysbiosis. The production of proinflammatory mediators in serum and the colon was also reduced by administration of LL-LFCA. In vitro, LFCA derived from LL-LFCA decreased the messenger RNA expression of proinflammatory factors. The underlying mechanisms may involve inhibition of the nuclear factor kappa B (NF-κB) pathway. The results demonstrate that LL-LFCA ameliorates DSS-induced intestinal injury in mice, suggesting that LL-LFCA might be an effective drug for the treatment of inflammatory bowel diseases.


Assuntos
Antibacterianos/metabolismo , Colite/patologia , Colite/terapia , Lactococcus lactis/metabolismo , Lactoferrina/metabolismo , Fragmentos de Peptídeos/metabolismo , Proteínas Recombinantes/metabolismo , Animais , Colite/induzido quimicamente , Modelos Animais de Doenças , Disbiose/terapia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Microbioma Gastrointestinal/efeitos dos fármacos , Lactococcus lactis/genética , Lactococcus lactis/crescimento & desenvolvimento , Lactoferrina/genética , Camundongos , Fragmentos de Peptídeos/genética , Proteínas Recombinantes/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resultado do Tratamento
4.
Analyst ; 143(2): 511-518, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29200221

RESUMO

Herein, a novel ferrocene-rhodamine receptor conjugated with an allylimine bridge was facilely synthesized. This triple channel receptor can selectively and sensitively monitor Pd2+ ions through chromogenic, fluorogenic and electrochemical assays in aqueous medium with a low detection limit (8.46 × 10-9 M) and a fast response (<8 min). It can be applied as a fluorescent probe for effective survey of Pd2+ ions in living cells. Moreover, a plausible recognition mode was proposed and rationalized by theoretical calculations.


Assuntos
Corantes Fluorescentes , Metalocenos , Paládio/análise , Rodaminas , Células HeLa , Humanos , Íons
5.
Molecules ; 22(5)2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-28471375

RESUMO

Ten ferrocenyl bis-amide derivatives were successfully synthesized via the Ugi four-component reaction by treating ferrocenecarboxylic acid with diverse aldehydes, amines, and isocyanides in methanol solution. Their chemical structures were fully characterized by IR, NMR, HR-MS, and X-ray diffraction analyses. They feature unique molecular morphologies and create a 14-membered ring motif in the centro-symmetric dimers generated in the solid state. Moreover, the electrochemical behavior of these ferrocenyl bis-amides was assessed by cyclic voltammetry.


Assuntos
Amidas/química , Compostos Ferrosos/química , Amidas/síntese química , Cristalografia por Raios X , Técnicas Eletroquímicas , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Metalocenos , Espectrofotometria Infravermelho
6.
Can J Microbiol ; 62(11): 961-969, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27718591

RESUMO

PR39, a 4.7 kDa proline-rich antimicrobial peptide, acts as a cationic host defense peptide. In addition to killing bacteria, PR39 mediates inflammatory reactions, including cell proliferation, migration, wound healing, and angiogenesis. Here, we examined the antibacterial effects of this peptide. The synthetic gene fragment PR39 was inserted into the secretory expression vector plasmid pPG:612 of Lactobacillus casei, yielding the recombinant strain pPG:612-PR39/L. casei 393. In vitro antibacterial tests showed that expression of the PR39 peptide in recombinant L. casei resulted in antibacterial activity against Escherichia coli and Salmonella but had only minor antibacterial effects in Staphylococcus aureus. In addition, BALB/c mice fed the recombinant pPG:612-PR39/L. casei 393 grew better and had increased peripheral blood lymphocyte percentages, white blood cell numbers, and spleen indices than mice in the control group. Scanning electron microscopy showed that jejunum and duodenum villus height, crypt depth, and the ratio of villus height/crypt depth in the intestinal villi also increased. Moreover, mice fed the recombinant strain showed significantly lower mortality rates than the control group mice when challenged with the enterotoxigenic E. coli K88+. Thus, this recombinant expression system had the beneficial characteristics of both L. casei and PR39, supporting its potential as an animal feed additive.

7.
J Imaging Inform Med ; 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38502435

RESUMO

This study aims to investigate the maximum achievable dose reduction for applying a new deep learning-based reconstruction algorithm, namely the artificial intelligence iterative reconstruction (AIIR), in computed tomography (CT) for hepatic lesion detection. A total of 40 patients with 98 clinically confirmed hepatic lesions were retrospectively included. The mean volume CT dose index was 13.66 ± 1.73 mGy in routine-dose portal venous CT examinations, where the images were originally obtained with hybrid iterative reconstruction (HIR). Low-dose simulations were performed in projection domain for 40%-, 20%-, and 10%-dose levels, followed by reconstruction using both HIR and AIIR. Two radiologists were asked to detect hepatic lesion on each set of low-dose image in separate sessions. Qualitative metrics including lesion conspicuity, diagnostic confidence, and overall image quality were evaluated using a 5-point scale. The contrast-to-noise ratio (CNR) for lesion was also calculated for quantitative assessment. The lesion CNR on AIIR at reduced doses were significantly higher than that on routine-dose HIR (all p < 0.05). Lower qualitative image quality was observed as the radiation dose reduced, while there were no significant differences between 40%-dose AIIR and routine-dose HIR images. The lesion detection rate was 100%, 98% (96/98), and 73.5% (72/98) on 40%-, 20%-, and 10%-dose AIIR, respectively, whereas it was 98% (96/98), 73.5% (72/98), and 40% (39/98) on the corresponding low-dose HIR, respectively. AIIR outperformed HIR in simulated low-dose CT examinations of the liver. The use of AIIR allows up to 60% dose reduction for lesion detection while maintaining comparable image quality to routine-dose HIR.

8.
J Chromatogr A ; 1730: 465150, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38991603

RESUMO

The precise determination of polypeptide antibiotics (PPTs) in foods has been always challenging because of the interference of various endogenous peptides in complex matrix. Herin, a novel large-pore covalent organic framework (TABPT-SPDA-COF) with accessible pore size of 7.9 nm was synthesized as a solid phase extraction (SPE) absorbent for efficiently enriching four PPTs existed in foods originating from animals. The parameters of SPE process were systematically optimized. Subsequently, four PPTs were determined by UHPLC-MS/MS. Under the optimal conditions, TABPT-SPDA-COF shows outstanding enrichment capacity for PPTs in contrast to commercial absorbents ascribed to size selectivity and multiple interaction effects. The method exhibits excellent linear range (0.005-100 ng mL-1), satisfactory limits of detection (0.1 pg mL-1) as well as relative recoveries (86.2-116 %). This work offers a practicable platform to monitor trace PPTs from complex animal-derived foodstuffs.

9.
Eur J Intern Med ; 114: 49-57, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37062643

RESUMO

BACKGROUND: It has been proven that sodium-glucose co-transporter 2 inhibitors (SGLT2is) improve the prognosis of patients with heart failure, independent of the presence of diabetes mellitus. Whether SGLT2 inhibitors affect cardiac structural remodeling and cardiac function is still uncertain. METHODS: We included published randomized controlled trials (RCTs) to compare the effect of SGLT2is and control therapy in patients with or without heart failure. The meta-analysis was performed using Review Manager 5.3 software. RESULTS: A total of 15 RCTs with a total of 1343 patients were selected for this meta-analysis, 663 of whom were on SGLT2is treatment and 680 of whom were in the control group. SGLT2is significantly improved heart rate (HR) [MD: -2.74, 95% CI (-4.71, -0.77), P = 0.006], left atrium volume index (LAVi) [MD: -1.99, 95% CI (-3.23,-0.75), P = 0.002], E/e' [MD: -1.47, 95% CI (-1.83,-1.10), P<0.00001], left ventricular mass index (LVMi) [MD: -2.38, 95% CI (-4.35, -0.40), P = 0.02], left ventricular end-systolic volume (LVESV) [MD: -6.50, 95% CI (-11.15,-1.84), P = 0.006], and left ventricular ejection fraction (LVEF) [MD: 1.78, 95% CI (0.56,3.01), P = 0.004] in the total population. Subgroup analysis indicated that compared with other SGLT2is, empagliflozin significantly decreased LVEDV, LVESV,LVMi, LAVi, E/e', and increased LVEF (P<0.05). In addition, the cardiac anti-remodeling effects of SGLT2 are particularly significant in patients with heart failure. CONCLUSION: Our study showed that SGLT2is, particularly empagliflozin, significantly reverse cardiac remodeling in patients with heart failure. Empagliflozin may be a potentially promising agent to reverse cardiac remodeling in clinical practice.


Assuntos
Diabetes Mellitus Tipo 2 , Insuficiência Cardíaca , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Remodelação Ventricular , Ensaios Clínicos Controlados Aleatórios como Assunto , Função Ventricular Esquerda , Insuficiência Cardíaca/tratamento farmacológico , Volume Sistólico , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Glucose , Sódio , Diabetes Mellitus Tipo 2/tratamento farmacológico
10.
Eur J Pharmacol ; 959: 176087, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37777105

RESUMO

AIM: The present study aimed to evaluate the impact of sodium-glucose cotransporter-2 inhibitors (SGLT2is) on blood lipid profile. METHODS: We searched the PubMed, Cochrane Library, Medline, and EMBASE databases from the inception to July 2023 for randomized controlled trials (RCTs) comparing SGLT2i with placebo regarding lipid profile changes. The "Meta" package of R software was applied for data synthesis. RESULTS: A total of 28 RCTs were included and 5192 patients participated in the present study, including 2686 patients who received SGLT2is intervention and 2506 patients who were in the control group. SGLT2is significantly increased blood low density lipoprotein cholesterol (LDL-C) levels [mean difference (MD): 0.09 mmol/L, 95% confidence interval (CI) (0.03, 0.16), 95% prediction interval (PI) (-0.06, 0.24), P = 0.0046] and high density lipoprotein cholesterol (HDL-C) levels [MD: 0.08 mmol/L, 95% CI (0.06, 0.11), 95% PI (-0.00, 0.17), P < 0.0001]. However, we observed neutral effect of SGLT2is on total cholesterol (TC) [MD: 0.08 mmol/L, 95% CI (-0.08, 0.24), 95% PI (-0.24, 0.40), P = 0.3150] and triglyceride (TG) [MD: -0.03 mmol/L, 95% CI (-0.23, 0.16), 95% PI (-0.70, 0.63), P = 0.7382]. CONCLUSION: Our study determined that SGLT2is increase both LDL-C and HDL-C levels, but exerts not significant effect on TC and TG levels.


Assuntos
Glucose , Lipídeos , Humanos , LDL-Colesterol , Ensaios Clínicos Controlados Aleatórios como Assunto , Triglicerídeos , Sódio , HDL-Colesterol
11.
Exp Ther Med ; 25(1): 40, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36569445

RESUMO

Slow blood flow or no reflow following percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI) typically leads to an adverse prognosis. However, it is controversial whether to use prourokinase (Pro-UK) during PCI in patients with acute STEMI. The present meta-analysis compared the efficacy and safety of intracoronary Pro-UK administration in patients with acute STEMI. Published randomized controlled trials (RCTs) were analyzed to compare Pro-UK with non-Pro-UK treatment in patients with acute STEMI. PubMed, Cochrane Library and China National Knowledge Infrastructure were searched and meta-analysis was performed using Review Manager 5.3 software. A total of 13 RCTs were selected and 1,797 patients were considered in the meta-analysis, including 897 patients who received Pro-UK intervention and 900 patients who were in the control group. No significant heterogeneity was identified across these selected studies. Pro-UK therapy significantly decreased the incidence of major adverse cardiac events [risk ratio (RR), 0.68; 95% CI, 0.56-0.82, P<0.0001], left ventricular end-diastolic diameter [standardized mean difference (SMD), -0.26; 95% CI, -0.40 - -0.12; P=0.0003], corrected thrombolysis in myocardial infarction (TIMI) frame count [SMD, -0.45; 95% CI, -0.62 - -0.28; P<0.00001] and cardiac troponin I [SMD, -0.31; 95% CI, -0.46 - -0.17; P<0.0001]. In addition, Pro-UK administration increased TIMI grade 3 flow (RR, 1.16; 95% CI, 1.07-1.25; P=0.0003), TIMI myocardial perfusion grade 3 (RR: 1.39, 95% CI: 1.12-1.74, P=0.004), ST-segment resolution (RR, 1.23; 95% CI, 1.10-1.36; P=0.0002) and left ventricular ejection fraction (SMD, 0.38; 95% CI, 0.27-0.49; P<0.00001). No significant difference was identified in bleeding (RR, 1.12; 95% CI, 0.85-1.47; P=0.41). The present meta-analysis determined that intracoronary Pro-UK administration is efficacious and safe to decrease slow blood flow or no reflow phenomena following PCI and improve the prognosis of patients with acute STEMI.

12.
Food Chem ; 410: 135359, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36608555

RESUMO

An analytical method of microspheric brominated covalent organic framework (Br-COF)-online solid-phase extraction integrated with high-performance liquid chromatography (online SPE-HPLC) was proposed for efficiently enriching six polybrominated diphenyl ethers (PBDEs) in foods. The Br-COF microspheres were facilely prepared with uniformity and dispersion by a size-controllable synthesis at the room temperature. Attributed to multiple interactions of the halogen bonding, Van der Waals forces, hydrophobic interaction along with size-matching effect, Br-COF performed satisfactory extraction capacity for PBDEs compared with commercial adsorbents. Five primary influencing factors were optimized, including loading solvent, loading flow rate, elution solvent, elution flow rate and elution volume. Under the optimal parameters, the implement displayed excellent linear ranges (0.5-500 ng mL-1) and low detection limits (0.01-0.05 ng mL-1). The relative recoveries in six spiked food samples ranged from 87.8 to 119.7 % with relative standard deviations below 10 %. This research estabished a promising platform for quantitatively determining trace PBDEs in complex foods.


Assuntos
Éteres Difenil Halogenados , Estruturas Metalorgânicas , Éteres Difenil Halogenados/análise , Estruturas Metalorgânicas/química , Extração em Fase Sólida/métodos , Solventes/química , Alimentos
13.
Sci Adv ; 9(24): eadf3120, 2023 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-37327346

RESUMO

Human cord blood-derived γδ T cells (CBγδ) display a highly diverse TCRγδ repertoire and have a unique subtype composition different from fetal or adult peripheral blood counterparts. We expanded CBγδ in vitro using an irradiated Epstein-Barr virus-transformed feeder cell-based modified rapid expansion protocol (REP). Single-cell RNA sequencing tracked progressive differentiation of naïve CBγδ into cells expressing neoantigen-reactive tumor-infiltrating lymphocyte as well as tissue-resident memory precursor-like and antigen-presenting cell-like gene signatures. TCRγδ clonal tracing revealed a bias toward cytotoxic effector differentiation in a much larger proportion of Vδ2- clones compared to Vδ2+ clones, resulting in the former being more cytotoxic at the population level. These clonotype-specific differentiation dynamics were not restricted to REP and were recapitulated upon secondary nonviral antigen stimulations. Thus, our data showed intrinsic cellular differences between major subtypes of human γδ T cells already in operation at early postnatal stage and highlighted key areas of consideration in optimizing cell manufacturing processes.


Assuntos
Infecções por Vírus Epstein-Barr , Linfócitos T , Adulto , Humanos , Sangue Fetal , Herpesvirus Humano 4 , Receptores de Antígenos de Linfócitos T gama-delta/genética
14.
J Biol Chem ; 286(40): 35291-8, 2011 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21852230

RESUMO

The process of autophagy is situated at the intersection of multiple cell signaling pathways, including cell metabolism, growth, and death, and hence is subject to multiple forms of regulation. We previously reported that inhibition of isoprenylcysteine carboxylmethyltransferase (Icmt), which catalyzes the final step in the post-translational prenylation of so-called CAAX proteins, results in the induction of autophagy which enhances cell death in some cancer cells. In this study, using siRNA-mediated knockdown of a group of small GTPases that are predicted Icmt substrates, we identify Rac3 GTPase as a negative regulator of the process of autophagy. Knockdown of Rac3, but not the closely related isoforms Rac1 and Rac2, results in induction of autophagy. Ectopic expression of Rac3, significantly rescues cells from autophagy and cell death induced by Icmt inhibition, strengthening the notion of an isoform-specific autophagy regulatory function of Rac3. This role of Rac3 was observed in multiple cell lines with varying Rac subtype expression profiles, suggesting its broad involvement in the process. The identification of this less-studied Rac member as a novel regulator provides new insight into autophagy and opens opportunities in identifying additional regulatory inputs of the process.


Assuntos
Autofagia , Proteínas rac de Ligação ao GTP/metabolismo , Morte Celular , Linhagem Celular , Sobrevivência Celular , Células Cultivadas , Proteínas de Ligação ao GTP/metabolismo , Células HeLa , Humanos , Microscopia de Fluorescência/métodos , Isoformas de Proteínas , Processamento de Proteína Pós-Traducional , RNA Interferente Pequeno/metabolismo , Transdução de Sinais
15.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 5): o1294-5, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22590204

RESUMO

The asymmetric unit of the title compound, C(6)H(9)ClN(4), contains four independent mol-ecules (A, B, C and D). Their main difference is the torsion angles, ranging from 1.6 (5) to 5.9 (5)°, between the methyl group and the pyrimidine plane. A pair of inter-molecular N-H⋯N hydrogen bonds link mol-ecules A and C into a twisted dimer with a dihedral angle of 32.9 (1)° between the two pyrimidine rings, creating an R(2) (2)(8) motif. In the packing, each two mol-ecules of B, C and D form centrosymmetric dimers through two inter-molecular N-H⋯N hydrogen bonds, locally creating R(2) (2)(8) motifs. The dimers of C and D are alternately bridged by A into an infinite zigzag strip, locally creating two different R(2) (2)(8) motifs with dihedral angles of 32.9 (1) and 63.4 (1)° between the pyrimidine rings. Finally, these strips together with the dimers of B associate into a complicated three-dimensional framework.

16.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 4): o1262, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-22606191

RESUMO

In the title compound, C(11)H(13)N(3)O(2), the 1,2,3-triazole ring and the phenol ring form a dihedral angle of 55.46 (5)°. In the crystal, inversion-related mol-ecules associate through pairs of hy-droxy-phenol O-H⋯O hydrogen bonds, giving centrosymmetric cyclic dimers [graph set R(2) (2)(18)]. These dimers are linked into infinite chains along [001], giving an overall two-dimensional network structure parallel to the bc plane through hy-droxy O-H⋯N and triazole C-H⋯N hydrogen bonds.

17.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 5): o1353-4, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22590248

RESUMO

The title thia-calix[4]arene derivative, C(36)H(34)Br(2)O(8)S(4), adopts an unusual pinched cone conformation with the prop-oxy-substituted benzene rings inclined inward [forming a dihedral angle of 33.4 (1)°] and with the brominated benzene rings bent outward, making a dihedral angle of 66.1 (1)°. In the crystal, the mol-ecules form chains along [001] via C-H⋯S hydrogen bonds and S⋯S contacts [S⋯S = 3.492 (3) Å]. The chains are associated into bilayers through C-H⋯O hydrogen bonds, generating an R(2) (2)(10) motif.

18.
Acta Crystallogr C ; 67(Pt 7): o244-8, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21727634

RESUMO

The molecule of 3-(2-amino-6-chloropyrimidin-4-yl)-1,1-dimethylprop-2-yn-1-ol monohydrate, C(9)H(10)ClN(3)O·H(2)O, (I), shows a very polarized molecular-electronic structure, while the polarization is slight for 3-[2-amino-6-(3-hydroxy-3,3-dimethylprop-1-yn-1-yl)pyrimidin-4-yl]-1,1-dimethylprop-2-yn-1-ol, C(14)H(17)N(3)O(2), (II). In the supramolecular structure of (I), a combination of hard N-H···N hydrogen bonds and soft C-H···N hydrogen bonds creates a molecular column. Aromatic π-π stackings between the pyrimidine rings stabilize the column with perpendicular and centroid-centroid distances of 3.283 (3) and 3.588 (1) Å, respectively. Short Cl···Cl contacts further link neighbouring molecular columns, creating a hydrophilic tube in which water molecules are fixed by various hydrogen bonds. In the packing of (II), a one-dimensional molecular chain is formed through several contacts involving hard N-H···O(N) and O-H···O(N) and soft C-H···O hydrogen bonds. Interchain O-H···O hydrogen bonds link the chains giving a two-dimensional stepped network. It is anticipated that study of the influence of hydrogen bonding on the patterns of base pairing and molecular packing in aminopyrimidine structures will shed significant light on nucleic acid structures as well as their functions.


Assuntos
Ácidos Nucleicos/química , Propanóis/química , Pirimidinas/química , Pareamento de Bases , Cristalografia por Raios X , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Molecular
19.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 5): o1131-2, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21754442

RESUMO

The title compound, C(11)H(9)F(3)NO(+)·ClO(4) (-)·C(11)H(8)F(3)NO or [(C(11)H(8)F(3)NO)H(C(11)H(8)F(3)NO)]ClO(4), contains two 8-(2,2,2-trifluoro-eth--oxy)quinoline molecules, one of which combines a proton from perchloric acid to form the corresponding quinolinium cation. The quinolinium and quinoline rings form a cationic unit via an inter-molecular N-H⋯N hydrogen bond. The heterocyclic units are almost perpendicular to each other [inter-planar angle 86.97 (6)°]. In the crystal, each perchlorate anion bridges two adjacent cationic units and creates a chain by a combination of C-H⋯O hydrogen bonds. Two inversion-related chains associate into a mol-ecular column by π-π stacking inter-actions between the quinolinium rings. The perpendicular and centroid-centroid distances between adjacent quinolinium rings are 3.501 (3) and 3.634 (9) Å, respectively. The molecular column is linked to its neighbors, creating a two-dimensional network via the weak π-π stacking between the quinoline rings [perpendicular and centroid-centroid separations 3.340 (4) and 4.408 (4) Å, respectively]. Finally, a three-dimensional framework is formed by a combination of intermolecular C-F⋯π contacts. One -CF(3) group is disordered over two positions of equal occupancy.

20.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 5): o1110-1, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21754428

RESUMO

In the title compound, C(30)H(26)Br(2)O(4)S(4), the thia-calix[4]arene unit adopts a pinched cone conformation, with one of the ether-substituted rings bent towards the calix cavity and the two phenolic rings bent outwards. The phenyl rings make dihedral angles of 27.12 (9), 36.71 (10), 75.04 (8), and 76.01 (7)° with the virtual plane defined by the four bridging S atoms. The two opposite ether-substituted rings are almost parallel to each other, with an inter-planar anagle of 2.99 (12)°, while the two phenolic rings are nearly perpendicular to each other, making a dihedral angle of 74.52 (11)° and a Br⋯Br distance of 13.17 (2) Å. Two intra-molecular O-H⋯O hydrogen bonds between the OH groups and the same ether O atom stabilize the cone conformation. In the crystal, two different chains of mol-ecules, one with alternating and the other with tail-to-tail orientations, are formed by inter-molecular offset-face-to-face π-π stacking inter-actions with distances of 3.606 (3) to 4.488 (4) Šbetween the centroids of the aromatic rings.

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