12 research outputs found

    Transition-metal(ii) complexes with a tripodal hexadentate ligand, 1,1,1-tris[2-aza-3-(imidazol-4-yl)prop-2-enyl]ethane, exhibiting incomplete total or absolute spontaneous resolution

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    Crystal structures and crystallisation behaviours of a series of first-row transition-metal(II) complexes bearing 1,1,1-tris[2-aza-3-(imidazol-4-yl)prop-2-enyl]ethane (H3L), [MII(H3L)]Cl(ClO4) (M = Mn, Fe, Co, Ni and Zn) were examined. These compounds crystallise in an orthorhombic crystal system with a non-enantiogenic (Sohncke) space group P212121, resulting in spontaneous resolution of the chiral complex cations. Hydrogen bonds between the imidazole Nā€“H atoms in the tripodal ligand and chloride anions give enantiomorphic crystals with a homochiral three-dimensional network structure. In order to verify the spontaneous resolution of these compounds, solid-state circular dichroism spectra of the resulting single crystals were measured (KBr disk method). Unexpectedly, the observed spectra indicated that imbalanced formation of the enantiomorphic crystals (i.e., left-handed Ī›-form vs. right-handed Ī”-form complex cations) in all cases. Moreover, in the cases of NiII and ZnII compounds, predominant enantiomorphic crystals formed by spontaneous resolution were always the same (in at least ten of our recrystallisation experiments). These observations suggest that there is a certain (but as yet unknown) factor that affects the predominant deposition of either enantiomorphic crystal when spontaneous resolution takes place from a solution of a racemic mixture in which rapid racemisation occurs

    Neural Model Extraction for Model-Based Control of a Neural Network Forward Model

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    Neural networks have been widely used to model nonlinear systems that are difficult to formulate. Thus far, because neural networks are a radically different approach to mathematical modeling, control theory has not been applied to them, even if they approximate the nonlinear state equation of a control object. In this research, we propose a new approachā€”i.e., neural model extraction, that enables model-based control for a feed-forward neural network trained for a nonlinear state equation. Specifically, we propose a method for extracting the linear state equations that are equivalent to the neural network corresponding to given input vectors. We conducted simple simulations of a two degrees-of-freedom planar manipulator to verify how the proposed method enables model-based control on neural network forward models. Through simulations, where different settings of the manipulatorā€™s state observation are assumed, we successfully confirm the validity of the proposed method

    The effect of solvent molecules on crystallisation of heterotrinuclear MIIā€“TbIIIā€“MII complexes with tripodal nonadentate ligands

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    The crystal structures and crystallisation behaviours of MIIā€“TbIIIā€“MII heterotrinuclear complexes, [(L)MTbM(L)]NO3 (M = Mn and Zn; L3āˆ’ stands for a conjugated base of H3L = 1,1,1-tris[(3-methoxysalicylideneamino)methyl]ethane), obtained from various organic solvents (MeOH, EtOH, CH2Cl2 and CHCl3) were investigated. The trinuclear complex cation has two asymmetric centres (Ī” or Ī›) at two MII sites as a result of the twisted tripodal arms of L3āˆ’. Single-crystal X-ray diffraction analysis revealed that all the analysed Znā€“Tbā€“Zn complexes had homochiral structures (Ī”,Ī”- or Ī›,Ī›-enantiomers) in each single crystal; however, the type of crystallisation behaviour showed clear differences depending on the type of solvent molecule. Specifically, crystallisation from MeOH or CH2Cl2 resulted in the exclusive formation of the Ī›-conglomerates with the Ī›,Ī›-enantiomersā€”a phenomenon we recently termed ā€˜absolute spontaneous resolutionā€™. The analogous Mnā€“Tbā€“Mn complex crystallised from MeOH also resulted in the same phenomenon as that of Znā€“Tbā€“Zn. In contrast, the meso-type (Ī”,Ī›) achiral isomer of the Mnā€“Tbā€“Mn complex was deposited for the first time in a series of MIIā€“LnIIIā€“MII trinuclear complexes from a CH2Cl2 or EtOH solution. Density functional theory calculations were performed to compare the thermodynamic stability of homochiral (Ī›,Ī›) and meso-type (Ī”,Ī›) complex cations of [(L)MnTbMn(L)]+ in MeOH and EtOH. Results were consistent with the molecular structures observed in the crystallographic analysis of the compounds deposited from these solvents

    DataSheet1_A Bayesian approach for constituent estimation in nucleic acid mixture models.docx

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    Mass spectrometry (MS) is a powerful analytical method used for various purposes such as drug development, quality assurance, food inspection, and monitoring of pollutants in the environment. In recent years, with the active development of antibodies and nucleic acid-based drugs, impurities with various modifications are produced. These can lead to a decrease in drug stability, pharmacokinetics, and efficacy, making it crucial to differentiate these impurities. Previously, attempts have been made to estimate the monoisotopic mass and ion amounts in the spectrum generated by electrospray ionization (ESI). However, conventional methods could not explicitly estimate the number of constituents, and discrete state evaluations, such as the probability that the number of constituents is k or k+1, were not possible. We propose a method where, for each possible number of constituents in the sample, mass spectrometry is modeled using parameters like monoisotopic mass and ion counts. Using Simulated Annealing, NUTS, and stochastic variational inference, we determine the parameters for each constituent number model and the maximum posterior probability. Finally, by comparing the maximum posterior probabilities between models, we select the optimal number of constituents and estimate the monoisotopic mass and ion counts under that scenario.</p

    Suture Granuloma Showing False-Positive Findings on FDG-PET

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    We report a case of a 33-year-old male with a mixed germ-cell testicular tumor. Postoperative follow-up FDG-PET revealed concentration of FDG in the left inguinal area which is not tumor metastasis or local recurrence but suture reactivity granuloma. In this paper, we reviewed suture granulomas associated with false-positive findings on FDG-PET after surgery. If FDG-PET will be used more frequently in the future, it will be necessary to refrain from using silk thread in order to prevent any unnecessary surgery

    Impact of Progressive Site-Directed Therapy in Oligometastatic Castration-Resistant Prostate Cancer on Subsequent Treatment Response

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    The purpose of this study was to evaluate the impact of progressive site-directed therapy (PSDT) for oligometastatic castration-resistant prostate cancer (OM-CRPC) on the efficacy of subsequent androgen receptor axis-targeted (ARAT) drugs, and to demonstrate the possibility of prolonging overall survival (OS). We performed a retrospective analysis of 15 OM-CRPC patients who underwent PSDT and subsequently received first-line ARAT drugs (PSDT group) and 13 OM-CRPC patients who were treated with first-line ARAT drugs without PSDT (non-PSDT group). PSDT was performed with the intention of treating all progressing sites detected by whole-body diffusion-weighted MRI with radiotherapy. Thirteen patients (86.7%) treated with PSDT had a decrease in PSA levels, which was at least 50% in 10 (66.7%) patients. The median PSA progression-free survival (PFS) for PSDT was 7.4 months. The median PSA-PFS for ARAT was 27.2 months in patients in the PSDT group and 11.7 months in the non-PSDT group, with a significant difference between the two groups (hazard ratio [HR], 0.28; p = 0.010). The median OS was not reached in the PSDT group and was significantly longer than 44.5 months in the non-PSDT group (HR, 0.11; p = 0.014). In OM-CRPC, PSDT may improve the efficacy of subsequent ARAT and OS
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