RESUMEN
The leaves of Vernonia amygdalina Delile of the family Asteraceae(also known as "bitter leaf"), rich in biological activities, are used as both medicine and food for a long time in West tropical Africa. They have been introduced into Southeast Asia and Fujian and Guangdong provinces of China in recent years. However, little is known about the properties of the plant in traditional Chinese medicine(TCM), which limits its combination with other Chinese medicinal herbs. In this study, 473 articles on V. amygdalina leaves were selected from PubMed, Web of Science, CNKI, Wanfang Data and VIP to summarize their components, pharmacological effects and clinical research. V. amygdalina leaves presented anti-microbial, hypoglycemic, anti-hypertensive, lipid-lowering, anti-tumor, anti-inflammatory, antioxidant, and other pharmacological effects. On the basis of the theory of TCM properties, the leaves were inferred to be cold in property and bitter and sweet in flavor, acting on spleen, liver, stomach and large intestine and with the functions of clearing heat, drying dampness, purging fire, removing toxin, killing insects and preventing attack of malaria. They can be used to treat dampness-heat diarrhea, interior heat and diabetes, malaria, insect accumulation and eczema(5-10 g dry leaves by decoction per day and an appropriate amount of crushed fresh leaves applying to the affected area for external use). Due to the lack of TCM properties, V. amygdalina leaves are rarely used medicinally in China. The determination of medicinal properties of the leaves is conducive to the introduction of new exotic medicinal herbs and the development of new TCM resources, which facilitated further clinical application and research and development of Chinese medicinal herbs.
Asunto(s)
Plantas Medicinales , Vernonia , Antioxidantes , Medicina Tradicional China , Extractos Vegetales/farmacología , Hojas de la PlantaRESUMEN
Deep insights into and substantial enhancement of the effective anisotropy energy barrier for magnetization reversal (Ueff) are vitally important for the technological applications of dysprosium(III)-based single-molecule magnets (Dy-SMMs). To fully refine the ligand-field effect on spin relaxation, four centrosymmetric {Dy2} entities with formula [Dy2(CH3OH)2L2(RCOO)2] (H2L = 2-hydroxy-N'-((pyridin-2-yl)methylene)benzohydrazide) have been solvothermally prepared by varying the side groups of carboxylate coligands (RCOO-, R = CF3 for 1, H for 2, CH3 for 3, and Cp2Fe for 4). Structural analyses reveal that all of the DyIII carriers in 1-4 have the same N2O6 donor environments, and the non-coordinative R groups attached to the equatorial carboxylate bridges have not substantially changed the binding ability of the shortest Dy-Ophenolate bonds located at the axial position of the ligand field. Interestingly, the side groups have monotonically decreased the zero-field Ueff barriers of these weak antiferromagnetically coupled {Dy2} analogues from 721 K down to 379 K. Further electronic structure calculations demonstrate that the main magnetic axes of 1-4 are highly dominated by these comparable Dy-Ophenolate short bonds, and the g tensors have produced gradually increased transverse components responsible significantly for the decreased Ueff barriers. Additionally, thermally assisted relaxations occur preferably through the second (for 1) and the first (for 2-4) Kramer doublets. These interesting findings afford a new side-group effect to comprehensively understand the magnetostructural relationships and advance the rational design of high-performance Dy-SMMs.
RESUMEN
One mononuclear complex [Dy(Htpy)(NO3)2(acac)] (1) and a tpy--extended 1D chain {[Dy(CH3OH)(NO3)2(tpy)]·CH3OH}n (2) (Htpy = 4'-(4-hydroxyphenyl)-2,2':6',2''-terpyridine, Hacac = acetylacetone) were successfully designed to investigate the effect of bond length tuning around the DyIII cation on the magnetic dynamics of single-molecule magnets (SMMs). Interestingly, two magnetic entities possess the same local coordination sphere (N3O6-donor) as well as the configuration (Muffin, Cs) of dysprosium centers. Only a slight difference in structure results from purposefully substituting the acetylacetone ligand in 1 with hydroxyl oxygen from tpy- linkage and one methanol molecule in 2. However, the remarkable differences in dynamics behavior were clearly found between them. Compound 1 possesses a thermal-activated effective energy barrier (Ueff/kB) of 22.7 K under a 0 kOe direct current (dc) field and negligible hysteresis loop at 2.0 K, while complex 2 shows high-performance SMM behavior with the largest energy barrier of 354.36 K among the reported nine-coordinated DyIII-based systems and the magnetic hysteresis up to 4.0 K at a sweep rate of 200 Oe s-1. These experimental results combined with the previous reported data reveal that the shortest bond and the bond length difference around the DyIII center synergistically determine the dynamics of SMMs. The uniaxial anisotropy increases with the decrease of the shortest bond and the increase of the bond length difference, which is confirmed by the theoretical calculations.
RESUMEN
Three isostructural pillared-layer frameworks with M-BDC-X layers supported by ditopic HL connectors, [M(HL)(BDC)0.5X] n (HL = 4'-(4-hydroxyphenyl)-4,2':6',4â³-terpyridine, BDC = terephthalate, M = Cd, X = Cl for (1), M = Cd, X = formate for (2), and M = Co, X = formate for (3)), were solvothermally synthesized, and used as photocatalysts for Pt-assisted visible-light-initiated hydrogen evolution from water splitting. These water-durable frameworks exhibit varied hydrogen production rates of 361.2, 271.3, and 327.5 µmol · g-1 · h-1 in 12 h due to their slightly different donor environments of the octahedral CdII and CoII ions. Further experimental and theoretical investigations reveal that the metal ions and the local coordination surroundings have essentially dominated the conduction band minimum and electric resistance of the charge transport, which play highly important roles for the improved catalytic hydrogen evolution ability. These findings demonstrate the electronic effect of the slightly ligand field modifications on the boosting hydrogen generation activity in the noble metal-assisted MOF photocatalytic systems.
RESUMEN
Mesenchymal stem cells (MSCs) have been applied in treating various diseases including myocardial infarction (MI) and achieved a bit of success; however, the decreased survival rate of MSCs after transplantation greatly limited the efficacy for cell therapy. How to improve the MSC survival rate in stem cell transplantation has undoubtedly become urgent and genetic engineering may be an ideal and feasible way. In this study, we explored the effects on MSCs survival and self-renewal by overexpression of integrin-linked kinase (ILK) in MSCs under hypoxic stimulation and aimed to reveal the molecular mechanisms from the point of paracrine function of MSCs. We first found that overexpression of ILK induced the expression and secretion of IL-6 increased significantly in MSCs under hypoxic stimulation, and the survival and self-renewal of MSCs exposed to hypoxia were enhanced after ILK overexpression. Then the activation of JAK2/STAT3 signaling was detected because of the increased IL-6, and an lncRNA, named lncTCF7, was upregulated remarkably, promoting the activation of Wnt pathway that was required for keeping cell viability and stemness of MSCs. Moreover, we further verified that inhibition of STAT3 signaling by WP1066 and silencing lncTCF7 expression eliminated the protective effects of ILK overexpression on cell survival and self-renewal of MSCs under hypoxic sitmulation. In conclusion, our results uncovered a novel function of ILK to promote MSC survival and self-renewal, suggesting more application potentials of MSC cell therapy on MI.
Asunto(s)
Proliferación Celular , Interleucina-6/metabolismo , Células Madre Mesenquimatosas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Vía de Señalización Wnt , Animales , Hipoxia de la Célula , Células Cultivadas , Células HEK293 , Humanos , Interleucina-6/genética , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Masculino , Células Madre Mesenquimatosas/fisiología , Proteínas Serina-Treonina Quinasas/genética , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Ratas , Ratas Sprague-Dawley , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismoRESUMEN
Bladder cancer is the most common malignancy with high recurrence. Currently, the long noncoding RNAs (lncRNAs) have been suggested to play vital roles in the pathogenesis of bladder cancer. The present study investigated the role of lncRNA MIR503 host gene (MIR503HG) in the pathogenesis of bladder cancer by using both in vitro and in vivo functional assays. The expression of MIR503HG was downregulated in bladder cancer tissues and cell lines. Low expression of MIR503HG was associated with advanced tumor stage, advanced histological grade, and lymph node metastasis. Ectopic expression of MIR503HG inhibited cell proliferation, cell growth, cell invasion, and migration, and also promoted cell apoptosis and inhibited cell cycle progression in SW780 cells. In parallel, T24 cells were used for loss-of-function studies. Knockdown of MIR503HG promoted the cancer cell proliferation and increased the migration and invasion abilities of T24 cells. In addition, knockdown of MIR503HG reduced the cell apoptotic rate in cancer cells and promoted cell cycle progression. Furthermore, MIR503HG overexpression decreased the epithelial-mesenchymal transition-related mRNA and protein levels of ZEB1, Snail, N-cadherin, and vimentin, with an increase in E-cadherin level. Consistently, knockdown of MIR503HG showed the opposite effects. In vivo xenograft, nude mice results showed that overexpression of MIR503HG suppressed the tumor growth and tumor metastasis. In conclusion, our results identified a novel lncRNA MIR503HG that exhibited significant antiproliferation, antimigration/invasion effects on bladder cancer cells both in vitro and in vivo, which may hold a therapeutic promise to treat bladder cancer.
Asunto(s)
Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , ARN Largo no Codificante/genética , Neoplasias de la Vejiga Urinaria/genética , Anciano , Animales , Antígenos CD/genética , Antígenos CD/metabolismo , Cadherinas/genética , Cadherinas/metabolismo , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Femenino , Humanos , Metástasis Linfática , Masculino , Ratones , Ratones Desnudos , Persona de Mediana Edad , Clasificación del Tumor , Estadificación de Neoplasias , ARN Largo no Codificante/antagonistas & inhibidores , ARN Largo no Codificante/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Factores de Transcripción de la Familia Snail/genética , Factores de Transcripción de la Familia Snail/metabolismo , Carga Tumoral , Neoplasias de la Vejiga Urinaria/metabolismo , Neoplasias de la Vejiga Urinaria/patología , Vimentina/genética , Vimentina/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismoRESUMEN
BACKGROUND AND AIM: Familial adenomatous polyposis (FAP) is the most common adenomatous polyposis syndrome. Patients with FAP are screened for germline mutations of two genes, APC and MUTYH. However, limited data exist on the clinical characterization and genotypic spectrum of FAP in China. This study was aimed to determine APC and MUTYH mutational status in a small cohort of FAP probands in China and to characterize the genotype-phenotype correlation in mutated patients. METHODS: Mutation screening of 46 unrelated probands was performed using multigene panels by next-generation sequencing. Clinical data of the index were used to assess genotype-phenotype correlations. RESULTS: Overall, 42 out of 46 (91.30%) unrelated probands found mutations, including 35 (76.09%) with APC mutations, 3 (6.52%) with MUTYH mutations, and 4 (8.70%) with both APC and MUTYH mutations. Ten APC genetic alterations variants were novel. The hereditary pattern of the family with both APC and MUTYH mutations was autosomal dominant inheritance. Upper gastrointestinal polyp was the most common extracolonic manifestations. The onset time for patients with both APC and MUTYH mutations was earlier than MUTYH mutation carriers and similar to APC mutation carriers. But the age of carcinogenesis for patients with both APC and MUTYH mutations was later than APC mutation carriers and similar to MUTYH mutation carriers. CONCLUSION: In this study, we show the importance of using multigene panels that allow for a parallel comprehensive screening. We suggest that genetic testing of patients with suspected adenomatous polyposis syndromes should include APC and MUTYH gene mutation analyses simultaneously.
Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Poliposis Adenomatosa del Colon/genética , ADN Glicosilasas/genética , Mutación , Poliposis Adenomatosa del Colon/diagnóstico , Poliposis Adenomatosa del Colon/etnología , Pueblo Asiatico/genética , Beijing/epidemiología , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Herencia , Humanos , Tasa de Mutación , Linaje , FenotipoRESUMEN
A centrosymmetric Dy2 single-molecule magnet (SMM) and its doped diamagnetic yttrium analogues, Dy0.19Y1.81 and Dy0.10Y1.90, were solvothermally synthesized to investigate the effects of intramolecular exchange coupling and quantum tunneling of magnetization (QTM) on the magnetic relaxation dynamics. Constructed from two hula-hoop-like DyIII ions and a pair of phenoxido groups, the antiferromagnetically coupled Dy2 exhibits a thermal-activated zero-field effective energy barrier (Ueff) of 277.7 K and negligible hysteresis loop at 2.0 K. The doping of a diamagnetic YIII matrix with 90.5% and 95.0% molar ratios reveals the single-ion origin of the Orbach channel, increases the relaxation time by partially quenching the QTM process, and induces an open hysteresis loop until 5.0 K. In contrast, an optimal dc field of 1.0 kOe improves the barrier height up to 290.1 K through complete elimination of the QTM and delays the relaxation time of the direct relaxation pathway. More interestingly, the collaborative dual effects of magnetic-site dilution and external magnetic field make the effective energy barrier and relaxation time increase 8.1% and 49 times, respectively. Thus, the overall magnetization dynamics of the Dy2 system systematically elaborate the inherent interplay of the QTM and Orbach processes on the effective energy barrier, highlighting the vital role of the relaxation time on the coercive hysteresis loop.
RESUMEN
A novel water and hydroxyl-extended one-dimensional dysprosium(III) chain was hydrothermally obtained, which exhibits a relatively high spin-reversal energy barrier of 88.7 K and intrachain ferromagnetic interaction with the coupling constant Jexch = 3.04 cm-1 calculated by fitting magnetic susceptibilities using POLY_ANISO program based on ab initio calculations. To deeply understand the respective role of the single-ion anisotropy and intrachain exchange on the effective energy barrier, three crystallographically isostructural analogues containing isotropic Gd(III)-, diamagnetic Y(III)-, as well as Y(III)-doped Dy0.05Y0.95 were prepared and characterized structurally and magnetically. Due to the absence of significant intrachain exchange interaction, the effective energy barrier of the Dy0.05Y0.95 decreased by 9.9 K as compared with that of parent dysprosium(III) chain. Thus, it can be concluded that the intrachain ferromagnetic coupling and the magnetic anisotropy of the Dy(III) ion synergistically enhance the effective energy barrier of the dysprosium(III) chain, in which the single-ion anisotropy becomes more predominant.
RESUMEN
BACKGROUND & AIMS: Diseases of the stomach, including gastric cancer and peptic ulcer, are the most common digestive diseases. It is impossible to visualize the entire stomach with the passive capsule currently used in practice because of the large size of the gastric cavity. A magnetically controlled capsule endoscopy (MCE) system has been designed to explore the stomach. We performed a prospective study to compare the accuracy of detection of gastric focal lesions by MCE vs conventional gastroscopy (the standard method). METHODS: We performed a multicenter blinded study comparing MCE with conventional gastroscopy in 350 patients (mean age, 46.6 y), with upper abdominal complaints scheduled to undergo gastroscopy at a tertiary center in China from August 2014 through December 2014. All patients underwent MCE, followed by conventional gastroscopy 2 hours later, without sedation. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of detection of gastric focal lesions by MCE, using gastroscopy as the standard. RESULTS: MCE detected gastric focal lesions in the whole stomach with 90.4% sensitivity (95% confidence interval [CI], 84.7%-96.1%), 94.7% specificity (95% CI, 91.9%-97.5%), a positive predictive value of 87.9% (95% CI, 81.7%-94.0%), a negative predictive value of 95.9% (95% CI, 93.4%-98.4%), and 93.4% accuracy (95% CI, 90.83%-96.02%). MCE detected focal lesions in the upper stomach (cardia, fundus, and body) with 90.2% sensitivity (95% CI, 82.0%-98.4%) and 96.7% specificity (95% CI, 94.4%-98.9%). MCE detected focal lesions in the lower stomach (angulus, antrum, and pylorus) with 90.6% sensitivity (95% CI, 82.7%-98.4%) and 97.9% specificity (95% CI, 96.1%-99.7%). MCE detected 1 advanced gastric carcinoma, 2 malignant lymphomas, and 1 early stage gastric tumor. MCE did not miss any lesions of significance (including tumors or large ulcers). Among the 350 patients, 5 reported 9 adverse events (1.4%) and 335 preferred MCE over gastroscopy (95.7%). CONCLUSIONS: MCE detects focal lesions in the upper and lower stomach with comparable accuracy with conventional gastroscopy. MCE is preferred by almost all patients, compared with gastroscopy, and can be used to screen gastric diseases without sedation. Clinicaltrials.gov number: NCT02219529.
Asunto(s)
Endoscopía Capsular/métodos , Gastroscopía/métodos , Gastropatías/diagnóstico , Adolescente , Adulto , Anciano , Animales , China , Femenino , Humanos , Magnetismo , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad , Centros de Atención Terciaria , Adulto JovenRESUMEN
Three new heterometallic single-molecule magnets (SMMs), [Dy2 Ni2 (bipy)2 (RC6 H4 COO)10 ] [bipy=2,2'-bipyridine, R=H (1), CH3 (2), and NO2 (3)], are synthesized solvothermally with different 3-substituted benzoate ligands (RC6 H4 COO- ), and are characterized both structurally and magnetically. Structural analyses reveal that the three entities are structurally analogous, exhibiting an approximately linear {Dy2 Ni2 } core bridged by ten carboxylate moieties from the RC6 H4 COO- ligands. A noncoordinating substituent group attached on the phenyl ring results in minor geometry distortions of 1-3, but causes a significant decrease in the Mulliken atomic charge on the axially shortest O donor through inductive and/or conjugative effects. Weak intramolecular ferromagnetic (for DyIII â â â DyIII ) and antiferromagnetic (for DyIII â â â NiII ) interactions with slightly different coupling strengths are observed in 1-3 at low temperatures, and the effective anisotropy barriers to block the magnetization reversal are 39.9, 25.9, and 2.8â cm-1 , respectively, under zero direct-current field. Abâ initio calculations reveal that ligand substitution by the noncoordinating electron-withdrawing/electron-donating group can give rise to good modulation of the energy gap between the two lowest Kramers doublets, as well as the orientation of the local easy axis of the DyIII ion magnetization. The directions of the local easy axis of the DyIII ion can further influence the dipole spin-spin interaction and the molecular anisotropy of the entire molecule, which, together with the energy separation between the ground and first excited ground states, become the significant factors determining the effective anisotropy barrier heights of 1-3. These important results demonstrate that the charge distributions of the ligand-field environments play essential roles in SMM performance, which should be considered seriously and utilized efficiently during the rational design of new, more feasible and practical SMMs.
RESUMEN
A bidentate ligand, 1-{4-[4-(1H-1,2,4-triazol-1-yl)phenoxy]phenyl}-1H-1,2,4-triazole (TPPT), has been designed and synthesized. By using TPPT as a building block for self-assembly with Cd(NO3 )2 â 4 H2 O and CdCl2 â 10.5 H2 O, novel 1D double-chain {[Cd(TPPT)(NO3 )2 ]â 3 H2 O}n (1) and 2D (4,4) layer [Cd(TPPT)Cl2 (H2 O)]n (2) have been constructed. When 1 was employed as a precursor and exposed to DMF or N,N'-dimethylacetamide (DMAC), the crystals of 1 dissolved and reassembled into two types of brown block-shaped crystals of 1D double chains: {[Cd(TPPT)2 (NO3 )2 ]â DMF}n (1 a) and {[Cd(TPPT)2 (NO3 )2 ]â DMAC}n (1 b). The anion-exchange reactions of complex 2 have also been investigated. After gently stirring crystals of 2 in CHCl3 /C2 H5 OH/H2 O containing NaBr, NaIâ 2 H2 O, or NaOAcâ 3 H2 O, the crystals retained their crystalline appearances. A remarkable single crystal to single crystal transformation was observed and 1D double chains of {[Cd(TPPT)Br2 ]â C2 H5 OH}n (2 a) and {[Cd(TPPT)2 I2 ]â CHCl3 }n (2 b), and 1D single chains of [Cd(TPPT)(H2 O)2 (CH3 COO)2 ]n (2 c), can be obtained. Luminescent properties indicate that 1 shows excellent selectivity for Ca(2+) and cyano complexes. To the best of our knowledge, this is the first example of a luminescent probe for Ca(2+) based on triazole derivatives.
RESUMEN
The 2-fold interpenetrated 3D framework 1 can be solvent-induced to noninterpenetrated framework 1' in a reversible single crystal-single crystal transformation fashion. In addition, 1' represents the first catalyst based on triazole to catalyze the aerobic homocoupling of various substituted arylboronic acids.
RESUMEN
For the purpose of investigating the coordination behavior of sterically congested alkenes and exploring the possibility of cofacial complexation in the polycyclic aromatic system for the formation of extended polymeric networks, a new tetradentate ligand, 1,1,2,2-tetrakis[4-(1H-1,2,4-triazol-1-yl)phenyl]ethylene (TTPE), has been designed and synthesized. By using TTPE as a building block with regard to the self-assembly with MnCl2 â 4 H2 O, a novel two-dimensional coordination framework {[Mn(TTPE)Cl2 ]â 4 CHCl3 }n (1) can be isolated. Anion-exchange and organic-group-functionalized aromatic guest TTPE-loaded host-guest complex experimental results indicate that coordinated Cl(-) anions in the 2D framework of 1 can be completely replaced with dissociative ClO4 (-) groups in an irreversible single-crystal-to-single-crystal transformation fashion, as evidenced by the anion-exchange products of {[Mn(TTPE)(H2 O)2 ](ClO4 )2 â 0.5 TTPEâ 5.25 H2 O}n (2). Interestingly, TTPE, acting as an organic template, was encapsulated in the confined space of the 2D grid of 2. To the best of our knowledge, such large organic molecules encapsulated in the reactive organic-group-functionalized aromatic-guest-loaded host-guest complex are unprecedented up to now. Luminescence measurements illustrate that 1 and 2 represent novel examples of sensing materials based on triazole derivatives. Further, 2 has been demonstrated by tuning the fluorescence response of porous metal-organic frameworks as a function of adsorbed small analytes.
RESUMEN
The two-dimensional (2D) metal-organic framework (MOF) [Cd(TPTZ)(H2O)2(HCOOH)(IPA)2]n (1; TPTZ = {4-[4-(1H-1,2,4-triazol-1-yl)phenyl]phenyl}-1H-1,2,4-triazole, IPA = isophthalic acid) has been constructed with the π-electron-rich aromatic ligand TPTZ, auxiliary ligand IPA, and the metal Cd(2+) ion with a d(10) configuration under solvothermal conditions. Complex 1 exhibits a strong ligand-originated photoluminescence emission, which is selectively sensitive toward electron-deficient nitroaromatic compounds, such as nitrobenzene (NB), 1,3-dinitrobenzene (m-DNB), and 1,4-dinitrobenzene (p-DNB), and nitro-aliphatic compounds, such as nitromethane (NM) and tris(hydroxymethyl)nitromethane. This property makes complex 1 a potential fluorescence sensor for these chemicals. Single-crystal X-ray diffraction studies revealed that dinuclear cadmium building units were further bridged by TPTZ ligands to give a four-connected uninodal net with the Schläfli symbol of [4.6(3).4.6(3).6(2).6(4)].
RESUMEN
Three new homometallic lanthanide complexes with mixed carboxylate-modified rigid ligands, [Ln(µ3-OH)(na)(pyzc)]n (na(-) = 1-naphtholate, pyzc(-) = 2-pyrazinecarboxylate, Ln = Dy (1), Yb (2), and Gd (3)), were solvothermally synthesized, and their structures and magnetic as well as photophysical properties were completely investigated. Complexes 1-3 are crystallographically isostructural, exhibiting linear chains with four bidentate bridging µ-COO(-) moieties encapsulated cubic {Ln4(µ3-OH)4}(8+) clusters repeatedly extended by 4-fold chelating-bridging-pyzc(-) connectors. Magnetically, the former two complexes with highly anisotropic Dy(III) and weak anisotropic Yb(III) ions in the distorted NO7 triangular dodecahedron coordination environment display field-induced slow relaxation of magnetization. Fitting the dynamic magnetic data to the Arrhenius law gives energy barrier ΔE/kB = 39.6 K and pre-exponential factor τo = 1.52 × 10(-8) s for 1 and ΔE/kB = 14.1 K and τo = 2.13 × 10(-7) s for 2. By contrast, complex 3 with isotropic Gd(III) ion and weak intracluster antiferromagnetic coupling shows a significant cryogenic magnetocaloric effect, with a maximum -ΔSm value of 30.0 J kg(-1) K(-1) at 2.5 K and 70 kOe. Additionally, the chromophoric na(-) and pyzc(-) ligands can serve as antenna groups, selectively sensitizing the Dy(III)- and Yb(III)-based luminescence of 1 and 2 in the UV-visible region by an intramolecular energy transfer process. Thus, complexes 1-3, incorporating field-induced slow magnetic magnetization and interesting luminescence together, can be used as composite magneto-optical materials. More importantly, these interesting results further demonstrate that the mixed-ligand system with rigid carboxylate-functionalized chromophores can be excellent candidates for the preparations of new bifunctional magneto-optical materials.
RESUMEN
A heterometallic complex {[Yb2(L)6Cd2][Cd(H2O)6]·6H2O}n (Yb-Cd) (H2L = oxidiacetic acid) was synthesized under hydrothermal conditions. In Yb-Cd, each L chelates to one Yb(3+) center and bonds to two Cd(2+) ions in an anti-anti configuration. Yb and Cd atoms are arrayed alternatively and connected by O-C-O bridges to form a cubic octahedral cage as the secondary building unit. Consequently, topological NaCl nets with high symmetry in the cubic space group Fd-3c have been constructed. The [Cd(H2O)6](2+) moieties lying in the porosity of anionic metal-organic framework (MOF) act as the thermodynamically stable species, required to balance the two negative charges of [Yb2(L)6Cd2](2-) in Yb-Cd. Interestingly, when Yb-Cd was employed as a precursor and emerged in the aqueous solution of Mn(ClO4)2·6H2O or Zn(ClO4)2·6H2O, a reversible single-crystal-to-single-crystal transformation process driven by [Cd(H2O)6](2+) cations has been exhibited to generate the heterotrimetallic coordination polymer {[Yb2(L)6Cd2][Mn(H2O)6]·6H2O}n (Yb-Cd-Mn) or {[Yb2(L)6Cd2][Zn(H2O)6]·6H2O}n (Yb-Cd-Zn). To the best of out knowledge, Yb-Cd-Mn and Yb-Cd-Zn are the first examples representing 4d-4f-3d polymers based on multicarboxylic acid. Luminescent studies reveal that Yb-Cd-Zn may serve as a good candidate of Ni(2+) a luminescent probe. To our knowledge, Yb-Cd-Zn represent the fist example of the 4d-4f-3d framework to exhibit luminescent selectivity for Ni(2+).
RESUMEN
Self-assembly from the predesigned Cu(II)5 secondary building unit (SBU) in the ternary Cu(II)-triazolate-sulfoisophthalate system generates three interesting magnetic samples: an open pillared-layer framework with nanosized Cu(II)30 metallamacrocycle-based sublayer (1), a (3,6)-connected 2-fold interpenetrating network consisting of alternating Cu(II)5 and Cu(II)1 cores (2), and a (4,8)-connected architecture constructed from centrosymmetric Cu(II)7 clusters and four-branched 5-sulfoisophthalate (sip(3-)) connectors (3). These various structures significantly result from the variable connectivity and the slight expansion of the predetermined conformationally flexible Cu(II)5 SBUs. Furthermore, these intriguing structural motifs in 1-3 essentially induce different magnetic phenomena. A field-dependent metamagnetic transition from antiferromagnetic ordering to weak ferromagnetism is observed in the frustrated Cu(II)30-based sublayer of 1. The paramagnetic Cu(II)1 core in 2 virtually contributes to an S = (1)/2 spin ground state due to the completely compensated magnetic moment in the 1,2,3-triazolate (ta(-))-bridged Cu(II)5 cluster containing ribbon. In contrast, strong antiferromagnetic interactions in the locally centrosymmetric Cu(II)7 cluster lead to an overall S = (1)/2 spin ground state of 3. Thus, the SBU-derived self-assembly strategy provides important hints for polymetallic cluster based high-dimensional magnetic materials, which also brings a new vision for the design and construction of novel functional materials.
RESUMEN
A new multidentate ligand 1-(9-(1H-1,2,4-triazol-1-yl)anthracen-10-yl)-1H-1,2,4-triazole (tatrz) was designed and synthesized. Using tatrz as a building block, three novel coordination frameworks, namely, {[Cu(tatrz)2(NO3)2]·(CH3OH)·4H2O}n (1), {[Cu(tatrz)2(H2O)2](BF4)2}n (2), and [Mn(tatrz)2(SCN)2(CH3OH)]·2H2O (3) can be isolated. Anion-exchange experiment indicates that NO3(-) anions in the two-dimensional (2D) copper framework of 1 can be completely exchanged by ClO4(-) in an irreversible single crystal-to-single crystal (SC-SC) transformation fashion, as evidenced by the anion-exchange products of {[Cu(tatrz)2(H2O)2](ClO4)2·4CH3OH} (1a). Further, if 1a was employed as a precursor in N,N-dimethylformamide (DMF), an isomorphic solvate of {[Cu(tatrz)2(DMF)2](ClO4)2·2H2O}n (1b) can be generated during the reversible dynamic transformation process. When 1 was immersed in CH3OH, a distinct 2D layer {[Cu(tatrz)2(NO3)2]·4.4CH3OH·0.6H2O}n (1c) was isolated. Interestingly, the solvent-exchange conversion is also invertible between 1 and 1c, which exhibits spongelike dynamic behavior with retention of crystalline integrity. If the 2-fold interpenetrating three-dimensional (3D) framework 2 is selected, it can be transformed into another 2-fold interpenetrating 3D framework {[Cu(tatrz)2(H2O)2](ClO4)2·5.56H2O}n (2a) in a reversible SC-SC transformation fashion. However, when the light yellow crystals of mononuclear complex 3 were exposed to trichloromethane containing aromatic organic anthracene (atan), through our careful observation, the crystals of 3 were dissolved and reassembled into dark brown crystals of 2D crystalline coordination framework {[Mn(tatrz)2(SCN)2]·(atan)}n (3a). X-ray diffraction revealed that in 3a, atan acting as an organic template was encapsulated in the confined space of the 2D grid. Luminescent measurements illustrate that 3a is the first report of multidimensional polymers based on triazole derivatives as luminescent probes of Mg(2+).
RESUMEN
PURPOSE: To evaluate the effectiveness and safety of minimally invasive percutaneous nephrolithotomy (mPCNL) without nephrostomy drainage tubes. METHODS: We prospectively enrolled 32 eligible patients with kidney stones at our hospital. Patients were randomly assigned to a conventional mPCNL group (ureteric Double-J stents and nephrostomy drainage tubes) or a tubeless mPCNL group (ureteric catheter but no drainage tubes). A single experienced surgeon performed all operations. RESULTS: At baseline, the two groups had similar age, maximum stone diameter, and gender distribution. There were no significant differences in operation time, presence of postoperative fever, stone clearance, and level of postoperative serum hemoglobin. However, the tubeless mPCNL group had significantly shorter hospital stays (3 vs. 4 days, p = 0.032) and significantly less back pain (5 patients vs. 14 patients, p = 0.003) than the conventional mPCNL group. CONCLUSIONS: No significant differences were found between conventional and tubeless mPCNL in safety issues and stone clearance rate. However, patients treated with tubeless mPCNL had shorter hospitalization stays and were less likely to experience back pain.