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• This study investigated the relationship between nutritional status measured by the Global Leadership Initiative on Malnutrition (GLIM) criteria and physical activity intensity, and the association of nutritional status and physical activity with ADLs in patients with sub-acute stroke. • Malnutrition was associated with a longer Sedentary behavior (SB) and shorter light-intensity physical activity (LIPA) time, but not moderate-to-vigorous physical activity (MVPA) time in patients with sub-acute stroke. • A longer SB time and shorter LIPA time were associated with FIM-M, and SB and LIPA mediated between nutrition status and ADLs in patients with sub-acute stroke. • The influence of nutritional status on physical activity and ADLs should be considered in stroke rehabilitation. To investigate the relationship between nutritional status measured by the Global Leadership Initiative on Malnutrition (GLIM) criteria and the intensity of physical activity, and to determine the association between these factors and the activities of daily living (ADLs) in patients with subacute stroke during hospitalization. A cross-sectional study. The study was conducted in the rehabilitation unit at a neurosurgical hospital. One hundred and twenty-eight patients with subacute stroke (N=128). Not applicable. Nutritional status was assessed using GLIM criteria. Sedentary behavior (SB), light-intensity physical activity (LIPA), and moderate-to-vigorous physical activity (MVPA) were measured using an accelerometer. Multiple regression analysis was used to investigate the relationship between nutritional status and intensity of physical activity. Moreover, the association of nutritional status and physical activity intensity with ADLs was determined using multiple regression analysis and mediation analysis. Malnutrition was associated with SB time (B = 16.241, P =.009) and LIPA time (B = -17.656, P =.002), but not MVPA time (B = -0.472, P =.776). SB time (B = -0.063, P =.009) and LIPA time (B = 0.093, P <.001) were associated with functional independence measure for motor function, while MVPA time (B = -0.080, P =.379) was not. SB time (coefficient = -10.785, P <.001) and LIPA time (coefficient = -12.054, P <.001) were significant mediators between nutrition status and ADLs. Malnutrition was associated with a SB time and LIPA time, but not MVPA time, in patients with sub-acute stroke. SB and LIPA times were associated with ADLs and mediated between nutrition status and ADLs in these patients. The association of nutritional status on physical activity and ADLs should be considered in stroke rehabilitation. [ABSTRACT FROM AUTHOR]

Endoscopic third ventriculostomy (ETV) for obstructive hydrocephalus and endoscopic biopsy (EB) for intraventricular and paraventricular tumors are standard therapies because they are minimally invasive procedures. Although EB-associated hemorrhagic risk has been well documented, there have been only a few reports on hemorrhagic risk associated with ETV. We conducted a single-institution retrospective study on the incidence of hemorrhage secondary to EB and/or ETV. We retrospectively reviewed patient characteristics, procedure, pathological findings, and complications including hemorrhage of 100 patients with intraventricular and paraventricular tumors who underwent EB and/or ETV at our institution from 2000 to 2020. EB/ETV combined surgery (combined group), EB-alone surgery (EB-alone group), and ETV-alone surgery (ETV-alone group) were performed in 44 (44%), 24 (24%), and 32 (32%) patients, respectively, and all procedures were successful. The rates of definitive and suggestive diagnoses in EB were 76.5% and 23.5%, respectively. Adverse events were observed in 6 patients. In the combined group, acute obstruction of the ETV stoma was observed in 1 patient and transient double vision was observed in 1 patient. Transient aqueductal stenosis/obstruction was observed in 2 patients in the EB-alone group. In the ETV-alone group, hemorrhage was observed in 2 patients; these patients developed intratumoral hemorrhage despite ETV-alone surgery. Subsequently, these 2 patients underwent tumor removal, and the histopathological diagnosis was atypical teratoid/rhabdoid tumor in both. For obstructive hydrocephalus with atypical teratoid/rhabdoid tumor, physicians must be aware of the risk of postoperative intratumoral hemorrhage after performing ETV. [ABSTRACT FROM AUTHOR]

Abstract Adenomatoid odontogenic tumor is a relatively rare tumor that typically occurs at the anterior part of the maxilla. Most cases arise as a central or intraosseous tumor accompanying an impacted tooth; thus, the radiological appearance resembles that of an odontogenic cyst. The tumor is divided into three subtypes depending on its location and relationship with the impacted tooth: the central variant associated with the crown of an unerupted tooth (follicular type); the central variant with no association with the crown of an unerupted tooth (extrafollicular type); and the peripheral (gingival) variant. Among them, the occurrence of peripheral variant is reportedly very rare, and they usually exhibit an epulis-like or fibroma-like appearance. This paper reports an unusual case of adenomatoid odontogenic tumor. Remarkably, the tumor extended into the buccal periodontal space, expanding the space possibly due to tumor growth without relevant absorption of labial alveolar bone. The adjacent gingiva looked normal except for the slight swelling. On histopathological analysis, the tumor showed no direct connection to the periodontal ligament, which may indicate the possible origin of this tumor as an epithelial remnant of the dental lamina in the peripheral gingiva. [ABSTRACT FROM AUTHOR]

Osteonecrosis of the jaw (ONJ) has been associated with antiresorptive therapy in both oncology and osteoporosis patients. This debilitating condition is very rare and advances in diagnosis and management may now effectively reduce the risk of its development and offer valuable treatment options for affected patients. This paper provides a case-based review of ONJ and application of the International Task Force on ONJ (referred to as the “Task Force”) recommendations for the diagnosis and management of ONJ. The Task Force was supported by 14 international societies and achieved consensus from representatives of these multidisciplinary societies on key issues pertaining to the diagnosis and management of ONJ. The frequency of ONJ in oncology patients receiving oncology doses of bisphosphonate (BP) or denosumab is estimated at 1%–15%, and the frequency in the osteoporosis patient population receiving much lower doses of BP or denosumab is estimated at 0.001%–0.01%. Although the diagnosis of ONJ is primarily clinical, imaging may be helpful in confirming the diagnosis and staging. In those with multiple risk factors for ONJ for whom major invasive oral surgery is being planned, interruption of BP or denosumab therapy (in cancer patients) is advised, if possible, before surgery, until the surgical site heals. Major oral surgery in this context could include multiple extractions if surgical extractions are required, not simple forceps extractions. ONJ development may be reduced by optimizing oral hygiene and postoperatively using topical and systemic antibiotics as appropriate. Periodontal disease should be managed before starting oncology doses of BP or denosumab. Local debridement may be successful in disease unresponsive to conservative therapy. Successful surgical intervention has been reported in those with stage 3 disease; less severe disease is best managed conservatively. Teriparatide may be helpful in healing ONJ lesions and may be considered in osteoporosis patients at a high fracture risk in the absence of contraindications. Resumption of BP or denosumab therapy following healing of ONJ lesions is recommended, and there have not been reports of subsequent local recurrence. [ABSTRACT FROM AUTHOR]

Objectives: We investigated the association among diagnosed osteoporosis, osteoporotic fractures, and carotid artery calcification (CAC) detected on panoramic radiographs. Additionally, we assessed whether osteoporosis or fractures could be predicted by an incidental finding of CAC.Study Design: One thousand twenty-one patients participated in this study. Patients completed a structured questionnaire. Logistic regression analysis adjusted for covariates was used to calculate the odds ratio (95% confidence interval) for diagnosed osteoporosis or fractures according to the presence of CAC. Extended receiver operating characteristic (ROC) curve analysis was used to clarify whether osteoporosis or fractures were predicted by the detection of CAC.Results: The odds ratios for diagnosed osteoporosis or fracture associated with CAC were 1.82 (1.02-3.24) and 0.77 (0.33-1.77), respectively. The areas under the ROC curves for identifying patients with osteoporosis or fractures according to the detection of CAC were 0.54 and 0.50, respectively.Conclusions: CAC may not be useful for identifying Japanese individuals with osteoporosis or those at risk of fracture, although the presence of CAC was significantly associated with a history of diagnosed osteoporosis without osteoporotic fractures. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the intramuscular changes on sonographic elastography (SE) after low-level static contraction of the masseter muscle, and to clarify the relationship with the total hardness and edematous change. Study design: Ten healthy volunteers performed sustained bilateral biting at 20% of maximal voluntary contraction for 10 min. The SE and magnetic resonance (MR) scans of the masseter muscles were performed before, immediately after, and 10 min after exercise. The masseter muscle elasticity index (MEI) ratio, muscle thickness, and intramuscular soft and hard areas distribution were evaluated on SE images. The signal to noise ratio (SNR), indicating the water content, was measured on MR images. Results: The soft area ratio showed significant correlations with the water content expressed as SNR. The hard area ratio showed significant correlations with the total muscle hardness expressed as the MEI ratio. Conclusion: Intramuscular soft and hard areas could be used both clinically and experimentally. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to clarify the changes, using magnetic resonance (MR) images, in the masseter muscles caused by low-level static contraction. Study design: Ten healthy male volunteers were enrolled in the study. The MR scans were performed before, immediately after, and 10 minutes after low-level static contraction. Two imaging sequences were acquired: a diffusion-weighted image and an iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) image. The apparent diffusion coefficient (ADC), the signal-to-noise ratio (SNR), and the thicknesses of the right and left masseter muscles were examined. Results: The ADC and SNR immediately after exercise were significantly higher than those before exercise and 10 minutes after exercise. The muscles were significantly thicker immediately after exercise than before exercise and 10 minutes after exercise. Conclusion: We confirmed the presence of edema in the masseter muscles caused by low-level static contraction using MR images. [Copyright &y& Elsevier]

Objective: The aim was to clarify the association between dental panoramic radiography measures of mandibular inferior cortical shape and biochemical markers of bone turnover in elderly men and women. Study design: Subjects were 80-year-old men (n = 85) and women (n = 153). Mandibular cortical shape and width were evaluated on dental panoramic radiographs. Bone formation and resorption, respectively, were estimated by serum levels of carboxy-terminal propeptide of type I collagen (PICP) and serum type I collagen carboxy-terminal telopeptide (ICTP). Results: Eroded cortices of the mandible were significantly associated with increased serum PICP levels (P = .005) in women. Lower mandibular cortical width quartiles were also significantly associated with increased serum PICP levels in men (P = .020) and women (P = .006). Conclusions: Mandibular inferior cortical measures detected on dental panoramic radiographs may be associated with bone formation rates and be useful in predicting osteoporosis in elderly Japanese men and women. [Copyright &y& Elsevier]

Summary: Numerous panoramic radiographs are taken annually to examine dental diseases, and using them for triaging individuals with general skeletal bone diseases, such as osteoporosis, would be economical and beneficial as dentists could refer these patients to medical professionals for further examination. Since the early 1990s, several studies have been performed regarding the utility of panoramic radiographs in triage screening for osteoporosis in dental clinics. Cortical indices of the mandible on panoramic radiographs, such as cortical width and cortical shape, are significantly associated with bone mineral density (BMD) of the general skeleton, biochemical markers of bone turnover and risk of osteoporotic fractures in postmenopausal women as well as elderly men. In prospective clinical trials, about 95% of postmenopausal women identified by trained general dental practitioners using cortical shape category on panoramic radiographs had low skeletal BMD or osteoporosis. Panoramic radiography indices may be likely useful triage screening tools for identifying individuals with an increased probability of having low skeletal BMD, osteoporosis and osteoporotic fractures. However, further investigations should be conducted worldwide to determine whether these indices are acceptable for triaging individuals with osteoporosis and referring them to medical professionals. [Copyright &y& Elsevier]

Abstract: The transition of Pt from a nanoparticle to a film on SiO2 particles modified by the sputtering system with barrel-type powder sample holder (the barrel sputtering system). X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements reveal that the Pt nanoparticles grow in size with an increase in the duration of sputter deposition. The morphology of Pt changes from highly dispersed nanoparticles to a worm-like structure followed by a continuous Pt film, depending on the amount of Pt modified. Transmission electron microscopy (TEM) measurements reveal that the thin Pt film in the worm-like structure has a uniform thickness of approximately 2.6nm, indicating film growth in a two-dimensional mode followed by an island mode. [Copyright &y& Elsevier]

Objectives: The objective of this study was to assess cortical measurements on panoramic radiographs in 80-year-old subjects to predict bone fracture and vascular disease risks. Methods: The cortical width and shape (normal cortex, mildly to moderately eroded cortex, and severely eroded cortex) were evaluated on 659 panoramic radiographs obtained from 262 men and 397 women, all of whom were 80 years old. At baseline, a general medical examination, including heel bone density, was performed in all subjects. Fractures and vascular disease occurring within 5 years after the baseline examination were determined in 191 subjects and in 108 subjects who died within 5 years after the baseline examination. Results: There were significant correlations between heel bone density and cortical width (r = 0.435, P < .001) and shape (r = 0.231, P < .001). However, cortical measurements on panoramic radiographs were not significantly associated with the occurrence of fractures and vascular disease within 5 years after the baseline examination. Conclusions: Among the elderly, cortical measurements on panoramic radiographs may be associated with bone mineral density and physical activity, but they are not useful markers for the subsequent occurrence of fractures and vascular disease. [Copyright &y& Elsevier]

Abstract: Micron-sized spherical polymer particles were homogeneously coated with Au, Ag, Pd, Cu, and Ni by the barrel sputtering technique. Surface coating was successfully performed independent of the sputtered metal and the diameter of the polymer particles used. Optical microscope observations revealed a mirror-like appearance with a color that depended on the coated metal. SEM and EDX studies revealed that the surface of metal-coated samples was very smooth and the sputtered metal was homogeneously distributed over the entire sample surface. The amount of coated metal was evaluated using TG–DTA and ICP-AES measurements. The thickness of the metal film was within several 10nm. [Copyright &y& Elsevier]

Purpose: To estimate the prognosis of simple bone cyst of the jaws. Subjects and Methods: We reviewed 132 of our own and published cases that received postoperative follow-up until healing or recurrence. The recurrence rate was obtained from treatment outcomes. The time to healing or recurrence was estimated from the distributions of the times of examinations that confirmed healing or recurrence. Results: Simple bone cyst lesions healed in 98 cases and recurred in 34 cases. The overall recurrence rate was 26%. The recurrence rate was 71% and 75% for cases with multiple cysts and cemento-osseous dysplasia, respectively. In most cases, healing or recurrence was confirmed within 3 years, 5 months of surgery. The maximum number of cases with healing and recurrence was observed 12 to 17 months and 2 to 2.5 years after surgery, respectively. Conclusion: The recurrence rate was higher than rates reported previously. We recommend that postoperative examination be continued until complete healing is confirmed radiographically, particularly in cases with multiple lesions or cemento-osseous dysplasia. Healing or recurrence should be confirmed within 3 years of treatment. [Copyright &y& Elsevier]

Objective: The purpose of this study was to evaluate whether subsequent vascular diseases and related death could be predicted by the presence of carotid artery calcification detected on panoramic radiographs among elderly persons. Study design: We evaluated 659 panoramic radiographs from 262 male and 397 female 80-year-old subjects and their general medical examination data to assess the relationship between the presence of carotid artery calcification and vascular disease risk at baseline examination. Of these subjects, the occurrence of vascular diseases within 5 years after baseline examination was examined in 191 subjects. Further, the causes of death were examined in 108 subjects who died within 5 years after baseline examination. Results: There was a significant difference in the history of past vascular diseases among subjects with and without carotid artery calcifications; however, no significant difference in the occurrence of subsequent vascular diseases was found among them. Further, there was no significant difference in the occurrence of vascular disease-related death within 5 years after baseline examination among subjects with and without carotid artery calcifications (P = 0.719). Conclusion: Our results suggest that the presence of carotid artery calcifications on panoramic radiographs may be related to the history of past vascular diseases; however, this is not a useful marker for subsequent vascular diseases and related death among 80-year-olds. [Copyright &y& Elsevier]

Purpose: The goal was to suggest guidelines for the treatment of developing tooth buds located on the fracture line of mandibular fractures. Patients and Methods: The long-term radiographic follow-up records of 28 patients with mandibular fractures involving 66 tooth buds were examined for the occurrence of abnormalities in development or eruption. The fates of the involved teeth were compared according to the fracture conditions and other factors, and the cause of the abnormalities was surveyed. Results: Abnormal findings were observed in 30 of 66 developing teeth (45%); these included deficient root formation, abnormal bend of the root, nodule formation on the root, partial obliteration of the pulp cavity, impaction, growth arrest, and external resorption. No relationship was found between the presence of abnormalities and the condition of the fracture or the developmental stage of the tooth buds. However, infection, rotation of the tooth bud, and a surgical wire passing through the follicular space were associated with arrested growth and impaction. Conclusions: The tooth buds present on the fracture line should be preserved except in cases of infection, and careful attention should be paid to avoiding further injury to the tooth bud and the soft tissues of the follicle at the time of surgery. [Copyright &y& Elsevier]

Objective: The purpose of this study was to determine whether simple visual estimation of the mandibular inferior cortex width on panoramic radiographs is useful for identifying postmenopausal women with low skeletal bone mineral density (BMD). Study design: Panoramic radiographs were made on 100 women aged 50-84 years who also had BMD assessment of the lumbar spine and femoral neck by dual-energy x-ray absorptiometry. The panoramic images were examined twice by 4 observers to evaluate the thickness of the mandibular inferior cortex. Results: Intraobserver agreement varied from moderate to almost perfect. Interobserver agreements varied from fair to almost perfect. Overall mean sensitivity, specificity and positive predictive value in identifying women with low BMD were 54.7%, 82.0%, and 72.5% in the lumbar spine and 51.8%, 82.2%, and 75.7% in the femoral neck, respectively. Conclusions: Our results suggest that simple visual estimation of the mandibular inferior cortex on panoramic radiographs may be useful for identifying postmenopausal women with low BMD. [Copyright &y& Elsevier]

To establish a unified classification system for mandibular osteomyelitis, various diagnostic terms were critically assessed and clinicopathologic findings of the lesions were carefully reviewed. We recommend classifying mandibular osteomyelitis into bacterial osteomyelitis and osteomyelitis associated with the synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. Other diagnostic terms were excluded because they were not appropriate for classification. Diagnostic criteria for bacterial osteomyelitis are suppuration and osteolytic change. The lesions are easily cured by antibiotic treatments. Mandibular osteomyelitis in SAPHO syndrome is characterized by nonsuppuration and a mixed pattern on radiography, with solid type periosteal reaction, external bone resorption, and bone enlargement. The presence of osteomyelitis in other bones, arthritis, or skin diseases (palmoplantar pustulosis, pustular psoriasis, and acne) strongly suggests this syndrome. Antibiotic therapy is usually ineffective and the symptoms of SAPHO syndrome are often persistent. [Copyright &y& Elsevier]

Abstract: Ordered mesoporous catalysts could open the door for new catalytic processes, based partly on novel principles, owing to their hitherto unprecedented intrinsic features. For the preparation of ordered mesoporous catalysts, many strategies have been described. These strategies and the essential properties of the resulting materials are described in the first part of this review. Catalytic processes over such mesoporous materials, especially such reactions where the specific features of ordered mesoporous catalysts are exploited, are described in the second part. [Copyright &y& Elsevier]

It is widely believed that the vasculature plays an important role in bone remodeling. We investigated the relationship between forearm endothelial function and bone mass in the lumbar spine in early postmenopausal women without a history of smoking or diabetes mellitus.We studied the forearm resistance artery endothelial function in 110 Japanese women—52 postmenopausal women with normal spinal bone mineral density (BMD), 36 postmenopausal women with osteopenia, and 22 osteoporotic postmenopausal women. Forearm blood flow (FBF) during reactive hyperemia and after sublingual nitroglycerin (NTG) administration was measured by strain-gauge plethysmography. BMD of the lumbar spine (L2–L4) was measured by dual-energy X-ray absorptiometry. After adjustment for age, body mass index, years since the start of menopause, and basal FBF, women with osteoporosis had a lower maximal FBF response to reactive hyperemia (28.4 ± 3.8 mL/min per 100 mL tissue) than those with normal BMD (39.8 ± 2.8 mL/min per 100 mL tissue) or osteopenia (35.6 ± 2.5 mL/min per 100 mL tissue) (P = 0.029). A significant increase in serum angiotensin-converting enzyme (ACE) activity (P = 0.042) and a significant decrease in the serum concentrations of nitrite/nitrate (P = 0.041) were noted in osteoporotic women compared to women with normal BMD or osteopenia.The present findings suggest that postmenopausal women with low BMD, especially those with osteoporosis, have impaired endothelial function in the forearm resistance arteries. [Copyright &y& Elsevier]

The neutron multiplier lead (Pb) containing Li 2 TiO 3 -0.5Li 4 SiO 4 –Pb was prepared, which aimed at the improvement of the tritium release performance of the lithium ceramic without an increase in lithium density. Li 2 TiO 3 -0.5Li 4 SiO 4 –Pb and that without Pb were irradiated at Kyoto University Research Reactor (KUR) with the thermal neutron flux of 5.5 × 1012 n s−1 cm−2 and the fast neutron flux of 1.2 × 1012 n s−1 cm−2. Fast neutrons can trigger the Pb (n , 2 n) reaction. The tritium release experiments were conducted using the tritium thermal desorption spectroscopy (tritium-TDS) system. Compared with Li 2 TiO 3 -0.5Li 4 SiO 4 , the tritium release rate at the lower temperature range was higher than that for Li 2 TiO 3 -0.5Li 4 SiO 4 –Pb. The tritium-TDS spectrum was also shifted to the lower temperature side. The isothermal heating experimental results confirmed that tritium in the form of gas species (HT) was controlled by the diffusion process, while the trapping and de-trapping process contributed to the total tritium release. Further, 3 keV D 2 + implantation with the fluence of 2.0 × 1022 D m−2 and subsequent TDS measurements were performed. It was shown that the D 2 release at the lower temperature side was increased for Li 2 TiO 3 -0.5Li 4 SiO 4 –Pb. Meanwhile, HD and HDO release at higher temperature side was significantly decreased. [ABSTRACT FROM AUTHOR]

Abstract A physical sputtering method was adopted to prepare graphene supported highly dispersed and uniform sized Ru NPs without using any solutions, surfactants and reductants. The Ru/G-spu exhibited excellent catalytic performance for HER and hydrolytic dehydrogenation of NaBH 4. Especially for HER in alkaline media, it performed superior electrocatalytic activity over Pt/C. The superior catalytic performance can be attributed to the high exposed surface area and dispersion of Ru NPs on graphene with the open 2D layer structure, which demonstrates the physical sputtering method is a facile and efficient technique to prepare graphene supported metal NPs with excellent structure and catalytic properties. Highlights • Graphene supported highly dispersed Ru NPs was prepared by physical sputtering. • The physical sputtering avoided using any solvent, surfactant and reducing agent. • The Ru/G-spu catalyst exhibited excellent catalytic performance for HER. [ABSTRACT FROM AUTHOR]

Article Title and Bibliographic Information: Age and trabecular features of alveolar bone associated with osteoporosis. Lee BD, White SC. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;100(1):92-8. Level of Evidence: 4 Purpose/Question: The purpose of this study was to determine if a combination of trabecular pattern, alveolar bone density, and clinical parameters is associated with a subject''s femoral/lumbar World Health Organization (WHO) bone mineral density class. Source of Funding: USPHS research grant R01 AR47529 from the National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health (NIH) Type of Study/Design: Case-control study [Copyright &y& Elsevier]

Original Article: Sewon L, Laine M, Karjalainen S, Doroguinskaia A, Lehtonen-Veromaa M. Salivary calcium reflects skeletal bone mineral density of heavy smokers. Arch Oral Biol 2004;49(5):355–8. Level of Evidence: 3b Purpose: The purpose of this study was to reveal the effect of heavy smoking on both salivary calcium concentration and calcaneal sonographic parameters representing bone density values. Source of Funding: Information not available Type of Study/Design: Case-control study [Copyright &y& Elsevier]

Poor oral care is associated with cardiovascular disease. The aim of this study was to determine the impact of tooth brushing behavior on the incidences of future cardiovascular events in a general population including patients with cardiovascular disease. This was a prospective observational study which included 692 participants (437 men and 255 women, mean age, 63 ± 16 years). The participants were divided into three groups according to the frequency and duration of tooth brushing: low frequency and short duration group (

Abstract: The optimum Pt and Ru atomic composition of a carbon-supported Pt–Ru alloy (Pt–Ru/C) used in a practical direct methanol fuel cell (DMFC) anode was investigated. The samples were prepared by the polygonal barrel-sputtering method. Based on the physical properties of the prepared Pt–Ru/C samples, the Pt–Ru alloy was found to be deposited on a carbon support. The microscopic characterization showed that the deposited alloy forms nanoparticles, of which the atomic ratios of Pt and Ru (Pt:Ru ratios) are uniform and are in accordance with the overall Pt:Ru ratios of the samples. The formation of the Pt–Ru alloy is also supported by the electrochemical characterization. Based on these results, methanol oxidation on the Pt–Ru/C samples was measured by cyclic voltammetry and chronoamperometry. The results indicated that the methanol oxidation activities of the prepared samples depended on the Pt:Ru ratios, of which the optimum Pt:Ru ratio is 58:42at.% at 25°C and 50:50at.% at 40 and 60°C. This temperature dependence of the optimum Pt:Ru ratio is well explained by the relationship between the methanol oxidation reaction process and the temperature, which is reflected in the rate-determining steps considered from the activation energies. It should be noted that at 25–60°C, the Pt–Ru/C with Pt:Ru=50:50at.% prepared by our sputtering method has the higher methanol oxidation activity than that of a commercially available sample with the identical overall Pt:Ru ratio. Consequently, the polygonal barrel-sputtering method is useful to prepare the practical DMFC anode catalysts with the high methanol oxidation activity. [Copyright &y& Elsevier]

Abstract: The present study investigated physical and electrochemical properties of carbon-supported Pt–Ru alloy (Pt–Ru/C) samples prepared on various carbon supports by using a sputtering system with barrel-type powder sample holder (the barrel sputtering system). For this system, the deposited Pt–Ru nano-particles had uniform sizes of less than 4nm and homogeneous atomic ratios of Pt and Ru of ca. 50:50at.% independent of a specific surface area of the carbon support. Further, the electrochemical properties of the prepared samples obtained from CO stripping voltammetry were almost identical. These were completely different from the result for wet process showing that the physical and electrochemical properties of samples prepared by an impregnation method changed with the specific surface area of the carbon support. [Copyright &y& Elsevier]