609 research outputs found

    Formation of pseudo[3]rotaxanes containing calix-bis-crowns and secondary ammonium ions and their thermodynamic stabilities in a solution: preorganization by second macrocycle and nonallosteric behavior exhibited by large crown cavities

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    This paper describes the formation of pseudo[3]rotaxanes containing calix[4]-bis-crowns, exhibiting a 1,3-alternate conformation and large crown cavities, and secondary ammonium ions. The first and second association constants of pseudo[3]rotaxane formation are moderate (K1 = 175, K2 = 100 M−1) and are higher than that of the corresponding pseudo[2]rotaxane (K = 24 M−1), consisting of a calix[4]-mono-crown and the same secondary ammonium ion

    BOROXINE CHEMISTRY: FROM FUNDAMENTAL STUDIES TO APPLICATIONS IN SUPRAMOLECULAR AND SYNTHETIC ORGANIC CHEMISTRY

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    Organoboroxine chemistry has recently received much attention because the boroxine formation reaction is a powerful tool for the construction of organized architectures. The reversible nature of this reaction may result in new materials that possess unprecedented levels of structural organization due to facilitation through self-correction, and switchable properties can be imparted by the reaction's reversibility. In addition, the effectiveness of boroxines (especially arylboroxines) has been recognised in the field of organic synthesis. The chemical properties of boroxines are certainly of great interest in organic synthesis and in the creation of new organic compounds. In this review, I describe the development of various molecular architectures that originate from the fundamental properties and structures of boroxines; I also describe the use of boroxines as reagents and catalysts.othe

    Superconductivity protected by spin-valley locking in ion-gated MoS2

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    Symmetry-breaking has been known to play a key role in noncentrosymmetric superconductors with strong spin-orbit-interaction (SOI). The studies, however, have been so far mainly focused on a particular type of SOI, known as Rashba SOI, whereby the electron spin is locked to its momentum at a right-angle, thereby leading to an in-planar helical spin texture. Here we discuss electric-field-induced superconductivity in molybdenum disulphide (MoS2), which exhibits a fundamentally different type of intrinsic SOI manifested by an out-of-plane Zeeman-type spin polarization of energy valleys. We find an upper critical field of approximately 52 T at 1.5 K, which indicates an enhancement of the Pauli limit by a factor of four as compared to that in centrosymmetric conventional superconductors. Using realistic tight-binding calculations, we reveal that this unusual behaviour is due to an inter-valley pairing that is symmetrically protected by Zeeman-type spin-valley locking against external magnetic fields. Our study sheds a new light on the interplay of inversion asymmetry with SOI in confined geometries, and its unprecedented role in superconductivity.Comment: 37 pages, 11 figures, http://meetings.aps.org/Meeting/MAR15/Session/G11.1

    Analysis of Surgical Outcomes of Diverticular Disease of the Colon

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    We analyzed retrospectively the surgical outcomes of diverticular diseases of the colon at the surgical division of Fukuyama Medical Center. Data were collected from 39 patients who underwent surgery for diverticular disease at Fukuyama Medical Center. Thirty-nine patients were admitted between 2005 and 2010. The mean age of the 39 patients was 63.6 years. The collected data included patient demographics, patient history, type of surgery and complications. Patients were divided into 2 groups, Elective vs. Emergent group, right vs. left colon group and laparotomy vs. laparoscopic approach. Multivariate analysis of the logistic model of morbidity revealed a significantly higher rate in the left colon and the Cox proportional hazards model clearly showed fewer postoperative hospital days with the laparoscopic approach. Surgical procedures should be decided in reference to the particular clinical and pathological features of diverticular disease to gain an acceptable morbidity and mortality rates

    Kawashima Procedure After Staged Unifocalizations in Asplenia With Major Aortopulmonary Collateral Arteries

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    We report a Kawashima procedure (total cavopulmonary shunt) successfully carried out for asplenia syndrome, pulmonary atresia, and major aortopulmonary collateral arteries. At the age of 8, the patient underwent staged bilateral unifocalizations using confluent central pulmonary arteries concomitant with bilateral modified Blalock-Taussig shunts. As the result of an interrupted inferior vena cava with azygous continuation, the patient required a Kawashima procedure with augmentation of the central pulmonary arteries for definitive palliation 1 year later. Cyanosis, respiratory distress, and ventricular function improved.Case repor

    Effects of Landiolol Hydrochloride on Intractable Tachyarrhythmia After Pediatric Cardiac Surgery

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    BackgroundWhile β-blockers can be effective in controlling tachyarrhythmias after pediatric cardiac surgery, a negative inotropic influence sometimes complicates their use. Landiolol hydrochloride is a novel, ultra-short-acting β-blocker recently developed in Japan. The drug has higher β1:β2 selectivity ratio and a less negative inotropic effect. This study retrospectively evaluates the efficacy and safety of landiolol in the management of tachyarrhythmias after pediatric cardiac surgery.MethodsA retrospective analysis was performed on 312 consecutive patients undergoing surgery for congenital heart disease. Twelve patients were treated with landiolol for critical tachyarrhythmia. The mean age of patients was 28.7 ± 10.6 months. Five junctional ectopic tachycardia, 2 atrial flutters, 1 paroxysmal supraventricular tachycardia, 1 atrial fibrillation, 1 atrioventricular reciprocating tachycardia with Wolff-Parkinson-White syndrome and 2 excessive sinus tachycardia were treated.ResultsThe mean loading and maintenance doses were 11.3 ± 4.0 and 6.8 ± 0.9 μg/kg per minute, respectively. Rate control was achieved in all patients. Landiolol reduced the heart rate from 169.7 ± 11.4 to 127.7 ± 7.5 beats per minute (p < 0.05) while blood pressure did not significantly change. Tachyarrhythmias were converted to sinus rhythm in 70.0% of the cases and the average time needed to achieve heart rate reduction was 2.3 ± 0.5 hours.ConclusionsLandiolol was efficacious in treating tachyarrhythmia in pediatric cardiac surgery. The desired negative chronotropic effect was achieved without significant hemodynamic compromise. The ultra-short half-life of landiolol provided rapid dose manipulation. This study suggests that landiolol is a promising option for the management of postoperative tachyarrhythmias in pediatric patients

    Five-state molecular switching of a [3]rotaxane in response to weak and strong acid and base stimuli

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    This communication describes the base- and acid-induced fivestate translational isomerization of a [3]rotaxane containing two pairs of N-arylamine and N-alkylamine centers as binding sites for two dibenzo[24]crown-8 components. Gradual molecular shuttling of this [3]rotaxane is achieved in response to both the amount and strength of the added acid or base.othe

    Formation of pseudo[3]rotaxanes containing calix-bis-crowns and secondary ammonium ions and their thermodynamic stabilities in a solution: preorganization by second macrocycle and nonallosteric behavior exhibited by large crown cavities

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    This paper describes the formation of pseudo[3]rotaxanes containing calix[4]-bis-crowns, exhibiting a 1,3-alternate conformation and large crown cavities, and secondary ammonium ions. The first and second association constants of pseudo[3]rotaxane formation are moderate (K1 = 175, K2 = 100 M-1) and are higher than that of the corresponding pseudo[2]rotaxane (K = 24 M-1), consisting of a calix[4]-mono-crown and the same secondary ammonium ion.othe

    Immunoescape in CRLM

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    The expression of programmed death 1 (PD-1) and programmed death-ligand 1 (PD-L1) indicate the efficacy of anti-PD-1/PD-L1 therapy in colorectal cancer (CRC), but are less useful for monitoring the efficacy of therapy of CRC liver metastasis (CRLM). This study investigated the effects of immune molecules on the prognosis of CRLM. We enrolled 71 patients with CRLM who underwent curative resection for CRC. We used immunohistochemistry to analyze the expression of PD-1, PD-L1, indoleamine-pyrrole 2,3-dioxygenase (IDO), and CD163 (a marker of tumor-associated macrophages [TAMs]) in metastatic tumors. The immune molecules PD-1, PD-L1, IDO, and TAMs were expressed in 32.3%, 47.8%, 45.0%, and 47.9% of metastatic CRC samples, respectively. The 5-year overall survival rates associated with immune molecule-positive groups were significantly better than in the negative groups (PD-1: 87.7% vs 53.2%, p = 0.023; PD-L1: 82.4% vs 42.3%, p = 0.007; IDO: 80.7% vs 43.5%, p = 0.007; TAMs: 82.6% vs 48.0%, p = 0.005). Multivariate analysis revealed PD-1 expression (p = 0.032, hazard ratio: 0.19), IDO expression (p = 0.049, hazard ratio: 0.37), and tumor differentiation (p<0.001, hazard ratio: 0.02) as independent prognostic indicators. PD-1 and TAMs in metastases were associated with less aggressive features such as smaller tumors. Furthermore, TAMs positively and significantly correlated with PD-1 expression (p = 0.011), PD-L1 expression (p = 0.024), and tended to correlate with IDO expression (p = 0.078). PD-1, PD-L1, IDO, and TAMs in CRLM were associated with less aggressive features and better prognosis of patients with CRC, indicating adaptive antitumor immunity vs immune tolerance. These molecules may therefore serve as prognostic markers for CRLM
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