Nuclear liquid-gas phase transition studied with antisymmetrized molecular dynamics

The nuclear liquid-gas phase transition of the system in ideal thermal equilibrium is studied with antisymmetrized molecular dynamics. The time evolution of a many-nucleon system confined in a container is solved for a long time to get a microcanonical ensemble of a given energy and volume. The temperature and the pressure are extracted from this ensemble and the caloric curves are constructed. The present work is the first time that a microscopic dynamical model which describes nuclear multifragmentation reactions well is directly applied to get the nuclear caloric curve. The obtained constant pressure caloric curves clearly show the characteristic feature of the liquid-gas phase transition, namely negative heat capacity (backbending), which is expected for the phase transition in finite systems.Comment: 31 pages, 8 figures, added formalism details, several improvements and new results, submitted to Phys. Rev.

Relevance of equilibrium in multifragmentation

The relevance of equilibrium in a multifragmentation reaction of very central $^{40}Ca+^{40}Ca$ collisions at 35 MeV/nucleon is investigated by using simulations of Antisymmetrized Molecular Dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time $t$ in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble which well reproduces the reaction ensemble at each reaction time $t$ for the investigated period $80\leq t\leq300$ fm/$c$. However, there are some other observables which show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables.Comment: 13 pages and 12figures; added a few sentences and corrected typos, accepted in Phys. Rev.

Approaches to the synthesis of penicillin

Several approaches to the synthesis of penicillin from 2-iminothioazolidine 50, from 2-thiothiazolidine 66 and by photocyclization of 77 and 78 were investigated. 2-Iminothiazolidine 50 was prepared from dibromoester 45 by the action of benzylamine followed by treatment of aziridine 46 with potassium or ammonium thiocyanate. Attempted introduction of a two-carbon unit into 50 by decomposition of ethyl diazoacetate afforded 51 and 52. Similarly, acetyl derivative 53 gave a carbon-hydrogen insertion product 54 upon pyrolysis. The reaction of 53 with ethyl lithiodiazoacetate produced an unexpected product 55. The synthesis of 2-thiothiazolidines by their reaction of aziridine 56 with carbon disulfide or potassium thiocyanate yielded only the undesired thiazolidines 57 and 60 respectively. However, the reaction of 66 with diethyl bromomalonate gave a 2-substituted thiazolidine 7G Reduction of 70 with sodium borohydride produced 71. Compounds 77 and 78 were synthesized by the coupling of 76 and 66 with phthalimidoacetyl chloride respectively. Attempted p-lactam formation by photolysis of 77 or 78 yielded only Norrish type II cleavage and no cyclization product. Biogenetically patterned approaches to the synthesis of 6-aminopenicillanic acid were also studied. Cysteine was protected at sulfur and nitrogen by the acetamidomethyl and tert-Boc groups respectively to give 86, which was condensed with aziridine 56 in the presence of DCC yielding 88. Photolysis of 88 followed by deprotection of sulfur gave the dimer 92. In another approach, a putative precursor of the thioaldehyde 89 was synthesized by a sequence in which cystine 93 was converted to N, N' -di-tert-Boc cystine 96 by treatment of tertbutoxycarbonylazide, the disulfide was cleaved by sodium metal in liquid ammonia, and the resulting thiol was immediately condensed with a-chloroacetophenone to give 97. Condensation of 97 with aziridine 56 in the presence of DCC produced 98 which upon photolysis afforded polymer

Boundary conditions for star matter and other periodic fermionic systems

Bulk fermionic matter, as it can be notably found in supernova matter and neutrons stars, is subject to correlations of infinite range due to the antisymmetrisation of the N-body wave function, which cannot be explicitly accounted for in a practical simulation. This problem is usually addressed in condensed matter physics by means of the so-called Twist Averaged Boundary Condition method. A different ansatz based on the localized Wannier representation has been proposed in the context of antisymmetrized molecular dynamics. In this paper we work out the formal relation between the two approaches. We show that, while the two coincide when working with exact eigenstates of the N-body Hamiltonian, differences appear in the case of variational approaches, which are currently used for the description of stellar matter. Some model applications with Fermionic Molecular Dynamics are shown

Biological basis and clinical study of glycogen synthase kinase-3b-targeted therapy by drug repositioning for glioblastoma

13301甲第4589号博士（医学）金沢大学博士論文要旨Abstract 以下に掲載：Oncotarget 8(14) pp.22811-22824 2017. Impactjournals. 共著者：古田 拓也, 淑瑠 ヘムラサビット, 董 宇, 宮下 勝吉, 木下 雅史, 内山 尚之, 林 康彦, 林 裕, 源 利成, 中田 光

Real-time analysis of the role of Ca2+ in flagellar movement and motility in single sea urchin sperm

Eggs of many marine and mammalian species attract sperm by releasing chemoattractants that modify the bending properties of flagella to redirect sperm paths toward the egg. This process, called chemotaxis, is dependent on extracellular Ca2+. We used stroboscopic fluorescence imaging to measure intracellular Ca2+ concentration ([Ca2+]i) in the flagella of swimming sea urchin sperm. Uncaging of cyclic GMP induced Ca2+ entry via at least two distinct pathways, and we identified a nimodipine-sensitive pathway, compartmentalized in the flagella, as a key regulator of flagellar bending and directed motility changes. We found that, contrary to current models, the degree of flagellar bending does not vary in proportion to the overall [Ca2+]i. Instead we propose a new model whereby flagella bending is increased by Ca2+ flux through the nimodipine-sensitive pathway, and is unaffected by [Ca2+]i increases through alternative pathways

Drug Repositioning for the Treatment of Glioma: Current State and Future Perspective

Gliomas are the most common primary brain tumors. Among them, glioblastoma (GBM) possesses the most malignant phenotype. Despite the current standard therapy using an alkylating anticancer agent, temozolomide, most patients with GBM die within 2 years. Novel chemotherapeutic agents are urgently needed to improve the prognosis of GBM. One of the solutions, drug repositioning, which broadens the indications of existing drugs, has gained attention. Herein, we categorize candidate agents, which are newly identified as therapeutic drugs for malignant glioma into 10 classifications based on these original identifications. Some drugs are in clinical trials with hope. Additionally, the obstacles, which should be overcome in order to accomplish drug repositioning as an application for GBM and the future perspectives, have been discussed