[A Case of Peritoneal Metastasis Resection from GIST of the Small Intestine with Focal Resistance Against Imatinib Mesylate].

A 69-year-old man was referred to our institute for the surgical resection of focal resistant peritoneal GIST during imatinib administration. He had been diagnosed with GIST of the small intestine with liver and peritoneal metastases, and imatinib treatment was initiated. Shortly after imatinib administration, the primary lesion perforated, and thus, partial resection of the small intestine was performed. Imatinib treatment was resumed after the first surgery, and he achieved partial response. However, computed tomography scans obtained 7 months after the first surgery showed focal progression, a peritoneal metastasis near the right kidney. Under the diagnosis of focally imatinib-resistant GIST, local resection of the metastatic tumor was performed. In this case, an exon 11 mutation of c-kit was noted initially. After the imatinib treatment, an additional point mutation was observed in exon 18 that caused resistance to imatinib. Therefore, imatinib treatment was reinitiated after the second surgery, and other metastases were well controlled. In case of GIST with multiple metastases, appropriate treatment should be selected based on the resistance of each lesion.

Thiolate-Protected Trimetallic Au∼20Ag∼4Pd and Au∼20Ag∼4Pt Alloy Clusters with Controlled Chemical Composition and Metal Positions.

The mixing of heteroelements in metal clusters is a powerful approach to generate new physical/chemical properties and functions. However, as the kinds of elements increase, control of the chemical composition and geometric structure becomes difficult. We succeeded in the compositionally selective synthesis of phenylethanethiolate-protected trimetallic Au∼20Ag∼4Pd and Au∼20Ag∼4Pt clusters, Au∼20Ag∼4Pd(SC2H4Ph)18 and Au∼20Ag∼4Pt(SC2H4Ph)18. Single-crystal X-ray structural analysis revealed the precise position of each metal element in these metal clusters. Reacting with thiol at an elevated temperature was found to be important to direct the metal elements to the most stable positions. The electronic structures of these trimetallic clusters become more discretized than those of the related bimetallic clusters due to orbital splitting.

Tuning the electronic structure of thiolate-protected 25-atom clusters by co-substitution with metals having different preferential sites.

Trimetallic Au24-xAgxPd and tetrametallic Au24-x-yAgxCuyPd clusters were synthesized by the subsequential metal exchange reactions of dodecanethiolate-protected Au24Pd clusters. EXAFS measurements revealed that Pd, Ag, and Cu dopants preferentially occupy the center and edge sites of the core, and staple sites, respectively. Spectroscopic and theoretical studies demonstrated that the synergistic effects of multiple substitutions on the electronic structures are additive in nature.

Boron δ-doped (111) diamond solution gate field effect transistors.

A solution gate field effect transistor (SGFET) using an oxidised boron δ-doped channel on (111) diamond is presented for the first time. Employing an optimised plasma chemical vapour deposition (PECVD) recipe to deposit δ-layers, SGFETs show improved current-voltage (I-V) characteristics in comparison to previous similar devices fabricated on (100) and polycrystalline diamond, where the device is shown to operate in the enhancement mode of operation, achieving channel pinch-off and drain-source current saturation within the electrochemical window of diamond. A maximum gain and transconductance of 3 and 200µS/mm are extracted, showing comparable figures of merit to hydrogen-based SGFET. The oxidised device shows a site-binding model pH sensitivity of 36 mV/pH, displaying fast temporal responses. Considering the biocompatibility of diamond towards cells, the device's highly mutable transistor characteristics, pH sensitivity and stability against anodic oxidation common to hydrogen terminated diamond SGFET, oxidised boron δ-doped diamond SGFETs show promise for the recording of action potentials from electrogenic cells.