Alloy Design, Thermodynamics, and Electron Microscopy of Ternary Ti-Ag-Nb Alloy with Liquid Phase Separation.

The Ti-Ag alloy system is an important constituent of dental casting materials and metallic biomaterials with antibacterial functions. The binary Ti-Ag alloy system is characterized by flat liquidus lines with metastable liquid miscibility gaps in the phase diagram. The ternary Ti-Ag-based alloys with liquid phase separation (LPS) were designed based on the mixing enthalpy parameters, thermodynamic calculations using FactSage and Scientific Group Thermodata Europe (SGTE) database, and the predicted ground state diagrams constructed by the Materials Project. The LPS behavior in the ternary Ti-Ag-Nb alloy was investigated using the solidification microstructure analysis in arc-melted ingots and rapidly solidified melt-spun ribbons via trans-scale observations, combined with optical microscopy (OM), scanning electron microscopy (SEM) including electron probe micro analysis (EPMA), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The solidification microstructures depended on the solidification processing in ternary Ti-Ag-Nb alloys; macroscopic phase-separated structures were observed in the arc-melted ingots, whereas fine Ag globules embedded in the Ti-based matrix were observed in the melt-spun ribbons.

Design and fabrication of Ti-Zr-Hf-Cr-Mo and Ti-Zr-Hf-Co-Cr-Mo high-entropy alloys as metallic biomaterials.

Novel TiZrHfCr0.2Mo and TiZrHfCo0.07Cr0.07Mo high-entropy alloys for metallic biomaterials (bio-HEAs) were developed based on the combination of Ti-Nb-Ta-Zr-Mo alloy system and Co-Cr-Mo alloy system as commercially-used metallic biomaterials. Ti-Zr-Hf-Cr-Mo and Ti-Zr-Hf-Co-Cr-Mo bio-HEAs were designed using (a) a tree-like diagram for alloy development, (b) empirical alloy parameters for solid-solution-phase formation, and (c) thermodynamic calculations focused on solidification. The newly-developed bio-HEAs overcomes the limitation of classical metallic biomaterials by the improvement of (i) mechanical hardness and (ii) biocompatibility all together. The TiZrHfCr0.2Mo and TiZrHfCo0.07Cr0.07Mo bio-HEAs showed superior biocompatibility comparable to that of commercial-purity Ti. The superior biocompatibility, high mechanical hardness and low liquidus temperature for the material processing in TiZrHfCr0.2Mo and TiZrHfCo0.07Cr0.07Mo bio-HEAs compared with the Ti-Nb-Ta-Zr-Mo bio-HEAs gave the authenticity of the application of bio-HEAs for orthopedic implants with multiple functions.

Solidification Microstructures of the Ingots Obtained by Arc Melting and Cold Crucible Levitation Melting in TiNbTaZr Medium-Entropy Alloy and TiNbTaZrX (X = V, Mo, W) High-Entropy Alloys.

The solidification microstructures of the TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, and W) high-entropy alloys (HEAs), including the TiNbTaZrMo bio-HEA, were investigated. Equiaxed dendrite structures were observed in the ingots that were prepared by arc melting, regardless of the position of the ingots and the alloy system. In addition, no significant difference in the solidification microstructure was observed in TiZrNbTaMo bio-HEAs between the arc-melted (AM) ingots and cold crucible levitation melted (CCLM) ingots. A cold shut was observed in the AM ingots, but not in the CCLM ingots. The interdendrite regions tended to be enriched in Ti and Zr in the TiNbTaZr MEA and TiNbTaZrX (X = V, Mo, and W) HEAs. The distribution coefficients during solidification, which were estimated by thermodynamic calculations, could explain the distribution of the constituent elements in the dendrite and interdendrite regions. The thermodynamic calculations indicated that an increase in the concentration of the low melting-temperature V (2183 K) leads to a monotonic decrease in the liquidus temperature (TL), and that increases in the concentration of high melting-temperature Mo (2896 K) and W (3695 K) lead to a monotonic increase in TL in TiNbTaZrXx (X = V, Mo, and W) (x = 0 - 2) HEAs.

Long-term survival with extended lateral lymphadenectomy for lateral lymph node recurrence after laparoscopic abdominoperineal resection for rectal adenosquamous carcinoma: a case report.

The patient was a 54-year-old female who presented with the chief complaint of melena. Lower gastrointestinal endoscopy detected a type 1 tumor extending from the anal canal to the rectum. CT did not detect any distant metastasis. Proximal D3 lymphadenectomy with laparoscopic abdominoperineal resection was performed for stage IA rectal cancer. In the histopathological examination, the tumor was identified as stage IIIa adenosquamous carcinoma. Although the patient underwent postoperative adjuvant chemotherapy with S-1, a recurrent left lateral lymph node tumor was detected on CT and PET 12 months later. The patient underwent the treatment with mFOLFOX + bevacizumab for 6 months. However, the tumor continued to progress, and therefore, extended lateral lymphadenectomy was performed 21 months after the first surgery. The patient did not undergo postoperative adjuvant therapy and is alive without recurrence 90 months after the first surgery and 70 months after the reoperation. Adenosquamous carcinoma of the rectum is a rare histological type of colorectal cancer for which there is no effective treatment besides surgical resection, and its prognosis is known to be worse than that of adenocarcinoma. Since there has been no report of long-term survival after extended lateral lymphadenectomy for recurrent lateral lymph node tumors following surgery for adenosquamous carcinoma of the rectum, herein, we report the case with a review of the literature.

Skeletal Ni Catalysts Prepared from Amorphous Ni-Zr Alloys: Enhanced Catalytic Performance for Hydrogen Generation from Ammonia Borane.

Skeletal Ni catalysts were prepared from Ni-Zr alloys, which possess different chemical composition and atomic arrangements, by a combination of thermal treatment and treatment with aqueous HF. Hydrogen generation from ammonia borane over the skeletal Ni catalysts proceeded efficiently, whereas the amorphous Ni-Zr alloy was inactive. Skeletal Ni prepared from amorphous Ni30 Zr70 alloy had a higher catalytic activity than that prepared from amorphous Ni40 Zr60 and Ni50 Zr50 alloys. The atomic arrangement of the Ni-Zr alloy also strongly affected the surface structure and catalytic activities. Thermal treatment of the amorphous Ni-Zr alloys at a temperature slightly lower than the crystallization temperature led to an increase of the number of surface-exposed Ni atoms and an enhancement of the catalytic activities for hydrogen generation from ammonia borane. The skeletal Ni catalysts also showed excellent durability and recyclability.

Irradiation damage in multicomponent equimolar alloys and high entropy alloys (HEAs).

To maintain sustainable energy supply and improve the safety and efficiency of nuclear reactors, development of new and advanced nuclear materials with superior resistance to irradiation damage is necessary. Recently, a new generation of structural materials, termed as multicomponent equimolar alloys and/or high entropy alloys (HEAs), are being developed. These alloys consist of multicomponent elements for maximizing the compositional entropy, which stabilizes the solid solution phase. In this paper, preliminary studies on the irradiation damage in equimolar alloys and HEAs by High Voltage Electron Microscopy (HVEM) are reported [1-4]. (1) ZrHfNb equimolar alloys [1, 2]A multicomponent ZrHfNb alloy was prepared by a co-sputtering process using elemental Zr, Hf, and Nb targets using an AJA International ATC 2000-V system. A single-phase bcc solid solution was obtained in the ZrHfNb alloy with an approximately equiatomic ratio of its constituent elements. The irradiation-induced structural change in the ZrHfNb equimolar alloys with the bcc solid solution structure was investigated by HVEM using the Hitachi H-3000 installed at Osaka University. The polycrystalline bcc phase shows high phase stability against irradiation damage at 298 K; the bcc solid solution phase, whose grain size was about 20 nm, remained as a main constituent phase even after the severe irradiation damage that reached 10 dpa. (2) CoCrCuFeNi HEAs [3]A single-phase fcc solid solution was obtained in a CoCrCuFeNi alloy. The microstructure of the alloy depended on the preparation technique: a nanocrystalline CoCrCuFeNi alloy with an approximately equiatomic ratio of its constituent elements was obtained by a co-sputtering process with multi-targets, while polycrystalline structures were formed when the arc-melting method was used. Both nanocrystalline and polycrystalline structures showed high phase stability against fast electron irradiation at temperatures ranging from 298 K to 973 K; a fcc phase remained as the main constituent phase over 40 dpa of irradiation. The grain coarsening of the crystalline phase can be seen during the annealing in a nanocrystalline CoCrCuFeNi alloy, while the irradiation-induced grain coarsening did not occur at 773 K as well as at 298 K.

Comparison of characteristics and healing course of diabetic foot ulcers by etiological classification: neuropathic, ischemic, and neuro-ischemic type.

AIMS: To identify differences in the characteristics of patients with diabetic foot ulcers (DFUs) according to their etiological classification and to compare their healing time. METHODS: Over a 4.5-year period, 73 patients with DFUs were recruited. DFUs were etiologically classified as being of neuropathic, ischemic, or neuro-ischemic origin. Descriptive analyses were performed to characterize study subjects, foot-related factors, and healing outcome and time. Duration of healing was assessed using the Kaplan-Meier method. Healing time among the three types was compared using the log rank test. RESULTS: The number of patients manifesting neuropathic, ischemic, and neuro-ischemic ulcers was 30, 20, and 14, respectively. Differences were identified for age, diabetes duration, body mass index, hypertension, and estimated glomerular filtration rate. Patients with neuro-ischemic ulcers had better ankle-brachial index, skin perfusion pressure (SPP), and transcutaneous oxygen pressure values compared to those with ischemic ulcers. The average time in which 50% of patients had healed wounds was 70, 113, and 233 days for neuropathic, neuro-ischemic, and ischemic ulcers, respectively. Main factors associated with healing were age and SPP values. CONCLUSIONS: Based on the etiological ulcer type, DFU healing course and several patient factors differed. Failure to consider the differences in DFU etiology may have led to heterogeneity of results in previous studies on DFUs.

Randomized prospective trial comparing clinical outcomes 3 years after surgery by Marcy repair and Prolene Hernia System repair for adult indirect inguinal hernia.

PURPOSE: The use of mesh in the surgical repair of adult indirect inguinal hernias is widely recommended in Western countries, but no randomized controlled trials have so far been reported in Japan. The purpose of the present randomized prospective trial was to compare a mesh method with non-mesh method for surgical repair of primary adult indirect inguinal hernias in which the diameter of the internal inguinal ring was up to 3.0 cm (I-1 or I-2 of Japanese Hernia Society Classification). METHODS: Patients with a primary unilateral inguinal hernia and I-1 or I-2 surgical findings were randomized to undergo either Marcy repair or Prolene Hernia System repair. Primary endpoints were recurrence, infection, and pain, with follow-up continued for 3 years postoperatively. RESULTS: Ninety-one of 479 patients with an inguinal hernia during the study period did not meet the exclusion criteria, and 46 were allocated to Marcy repair and 45 were allocated to Prolene Hernia System repair. No recurrence was observed in either group, and no significant differences were identified between the groups in any of the primary endpoints. CONCLUSION: This randomized prospective trial of I-1 and I-2 inguinal hernias suggests that Marcy repair is not inferior to PHS repair. A large-scale randomized controlled trial appears warranted to confirm whether to use mesh for Japanese adult I-1 and I-2 hernias.

[Analysis of four patients with advanced gastric cancer undergoing gastrectomy after pre-operative combination chemotherapy using docetaxel, cisplatin and S-1].

We analyzed the clinical efficacy of pre-operative combination chemotherapy using docetaxel, cisplatin and S-1 for advanced gastric cancer. Four patients were enrolled and staging laparoscopy was performed. Patients received intravenous docetaxel and cisplatin (35 mg/m2) on day 1 and 15, and oral S-1 80 mg/m2 on day 1-14 every 4 weeks. Two patients received two courses of chemotherapy and two patients received three courses of chemotherapy. Neutropenia of more than grade 3 was found in 3 cases. All cases were PR on preoperative imaging. Curative operation was performed on three cases. Histological anti-tumor effect was judged to be grade 2 in 1 case and grade 1a in 3 cases. In the postoperative period, all patients received S-1-based adjuvant chemotherapy. The combination chemotherapy using docetaxel, cisplatin and S-1 plus operation was a candidate for the standard treatment strategy for advanced gastric cancer.

Solitary fibrous tumor in the pelvic cavity with hypoglycemia: report of a case.

A case of solitary fibrous tumor (SFT) in the pelvic cavity with hypoglycemia is reported. The patient was a 60-year-old man who was referred to our hospital for a closer examination of hypoglycemia. Computed tomography demonstrated a mass, measuring 14 x 9 cm in size, in the pelvic cavity. Magnetic resonance imaging showed the mass to have a low signal intensity on T1-weighted images and a high intensity on T2-weighted images. Laparotomy revealed no peritoneal dissemination nor lymph node metastasis. An en bloc excision of the tumor was performed with a good recovery, and the hypoglycemia disappeared. Histologically, the tumor was composed of spindle-shaped and oval cells in sarcoma, based on a moderate mitotic rate and cellularity. Immunohistochemically, the tumor was positive for CD34 and negative for keratin, alpha-smooth muscle actin, desmin, S100 protein, c-kit protein, and epithelial membrane antigen. Based on these findings, the tumor was diagnosed to be malignant SFT in the pelvic cavity.