Study on Multicomponent Systems by Means of Contrast Variation Small Angle Neutron Sccattering

この論文は国立情報学研究所の電子図書館事業により電子化されました。多種多様な相互作用が存在し得る多成分系においては、相互作用が選択的に働く事により特異な物性が発現する場合が多々存在する。中性子散乱では、軽水素と重水素を化学的に置換することにより、物理的な性質にほとんど影響を与える事無く散乱コントラストを変化させる「コントラスト変調法」が可能であり、この手法を精密に適用する事で、多成分間の相互作用をcross termとして定量的に観測する事が可能となる。本研究においては、両親媒性高分子が水/油/界面活性剤マイクロエマルジョン中で引き起こす効果や、タンパク質がリン酸カルシウムの結晶化を阻害する効果に対し、コントラスト変調中性子小角散乱法を用い、系内で織りなされる複雑な相互作用を分子論的に解明した

Multiple Digit Formation inXenopusLimb Bud Recombinants

AbstractWe prepared recombinant limb buds ofXenopustadpoles by grafting a mesenchyme mass of the hindlimb bud. TheXenopusrecombinant limb buds with dissociated and reaggregated mesenchyme developed more than 30 digits with cartilage segmentation, while those with undissociated mesenchyme developed a limb with normal cartilage pattern. Before the formation of multiple digits, a patchy expression pattern offgf-8,an AER marker, was observed in the distal region of recombinant limb buds.shh,a ZPA (zone of polarizing activity) marker, was expressed broadly in the distal region of recombinants. Recombinant limb buds with the reaggregated mesenchyme of anterior halves formed anterior digits with claws, and those with the mesenchyme of posterior halves formed posterior digits without claws. The temporal and spatial changes in the potency of multiple digit formation are discussed with reference to the regenerative capacity ofXenopuslimb buds

Tuning Neutron Resonance Spin-Echo Spectrometers with Pulsed Beams

The neutron spin-echo spectroscopy technique involving pulsed beams can be used to effectively access a wide range of space-time correlations of condensed matter. In this study, the features of this technique, in particular, the modulation of the intensity with zero effort (MIEZE) by using pulsed beams, which is based on the quantum-state manipulation of the neutron spin and energy, are comprehensively examined. A formulation of the MIEZE combined with the time of flight method (TOF MIEZE) is established by considering the characteristics of the pulsed neutron beams. Moreover, a parameter, namely, the detuning parameter, is introduced as a measure of the magnitude of detuning from the optimized instrumental state, known as the spin-echo condition. The phase and frequency shifts of the neutron intensity signals resulting from the TOF MIEZE under various configurations are investigated systematically. It is found that the detuning parameter equals the derivative of phase with respect to the TOF, whose zero-point corresponds to the spin-echo condition. The theoretical predictions on phase and frequency shifts by the established formulation are well validated by the experiments using an intense pulsed neutron source. The detuning parameter helps clarify the principle of the TOF MIEZE technique and can provide practical guidance regarding the implementation and optimization of spectrometers

Identification of a single base insertion in the COL4A5 gene in Alport syndrome

Identification of a single base insertion in the COL4A5 gene in Alport syndrome. We identified a novel mutation in the COL4A5 gene of a Japanese patient with Alport syndrome. A combination of in vitro amplification of the exons with single strand conformation polymorphisms (SSCP) analysis suggested the presence of a mutation in exon 48. Sequencing of the amplified DNA revealed a single base (T) insertion which was between nucleotides T 4750 and G 4751 within the methionine 1516. This mutation caused a shift in the reading frame of nine amino acids and introduced a premature termination signal that would be expected to lack about two-thirds of the noncollagenous (NCI) domain. This mutation may interfere with type IV collagen assembly leading to increased permeability and play a causative role in the glomerular basement membrane abnormality of this patient with typical Alport syndrome. Gene tracking by restriction enzyme NlaIII digestion revealed that the patient's mother is heterozygous whereas the patient's brother and one sister are normal, albeit they have hematuria and proteinuria. Without gene analysis, they would have been misdiagnosed. We propose that the diagnosis of Alport syndrome should be made on the basis of both clinical phenotypes and molecular defects

Bronchogenic cyst of the interatrial septum

Although bronchogenic cysts are the most common primary mediastinal cysts, intracardiac bronchogenic cysts are extremely rare. We report a case of a bronchogenic cyst of the interatrial septum in a 42-year-old woman who presented with recent onset of dyspnea on exertion. Cardiac investigations including transthoracic echocardiography and computed tomography revealed a cystic homogeneous mass in the interatrial septum. The patient underwent surgical resection, and the resultant atrial septal defect was repaired using an autologous pericardial patch. Histopathological examination of the resected specimen revealed findings consistent with a benign bronchogenic cyst. Although bronchogenic cysts are extremely rare, they should be considered in the differential diagnoses of intracardiac tumors. Complete resection of bronchogenic cysts is recommended primarily for diagnostic and potentially therapeutic purposes

Hepatic Arterial Infusion Chemotherapy Prior to Standard Systemic Chemotherapy in Patients with Highly Advanced Unresectable Liver Metastases from Colorectal Cancer: A Report of Three Patients

We administered hepatic arterial infusion chemotherapy (HAIC) prior to FOLFOX to three patients with unresectable liver metastases from colorectal cancer. The patients' disease state was found to be highly advanced based on both computed tomography findings and liver function tests. The treatment strategy included an initial administration of HAIC to control liver metastases and improve liver function in order to facilitate the subsequent safe administration of FOLFOX without drug loss. As the HAIC regimen, 1,000mg/m2 of 5-FU was administered weekly by continuous 5-h infusion after performing laboratory investigations through an implanted port-catheter system. After 3 HAIC cycles administered over 3 consecutive weeks, the mean alkaline phosphatase levels decreased from 969.3IU/l to 422IU/l due to shrinkage of the liver metastases. Thereafter, FOLFOX without drug loss could be safely initiated for all patients. Two patients succumbed 488 and 333 days after HAIC was initiated;the third patient is still alive and has been followed-up for 1215 days. The combined use of HAIC and standard systemic chemotherapy could be a feasible and efficacious treatment in highly advanced cases of liver dysfunction

Sclerite formation in the hydrothermal-vent “scaly-foot” gastropod — possible control of iron sulfide biomineralization by the animal

A gastropod from a deep-sea hydrothermal field at the Rodriguez triple junction, Indian Ocean, has scale-shaped structures, called sclerites, mineralized with iron sulfides on its foot. No other organisms are known to produce a skeleton consisting of iron sulfides. To investigate whether iron sulfide mineralization is mediated by the gastropod for the function of the sclerites, we performed a detailed physical and chemical characterization. Nanostructural characterization of the iron sulfide sclerites reveals that the iron sulfide minerals pyrite (FeS2) and greigite (Fe3S4) form with unique crystal habits inside and outside of the organic matrix, respectively. The magnetic properties of the sclerites, which are mostly consistent with those predicted from their nanostructual features, are not optimized for magnetoreception and instead support use of the magnetic minerals as structural elements. The mechanical performance of the sclerites is superior to that of other biominerals used in the vent environment for predation as well as protection from predation. These characteristics, as well as the co-occurrence of brachyuran crabs, support the inference that the mineralization of iron sulfides might be controlled by the gastropod to harden the sclerites for protection from predators. Sulfur and iron isotopic analyses indicate that sulfur and iron in the sclerites originate from hydrothermal fluids rather than from bacterial metabolites, and that iron supply is unlikely to be regulated by the gastropod for iron sulfide mineralization. We propose that the gastropod may control iron sulfide mineralization by modulating the internal concentrations of reduced sulfur compounds