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ABSTRACT: With a combination of magnetic susceptibility measurements and low-temperature neutron diffraction analyses, the magnetic structure of Li2FeP2O7 cathode has been solved. This pyrophosphate Li2FeP2O7 compound stabilizes into a monoclinic framework (space group P21/c), having a pseudolayered structure with the constituent Li/Fe sites distributed into MO6 and MO5 building units. The magnetic susceptibility follows a Curie-Weiss behavior above 50 K. Li2FeP2O7 shows a long-range antiferromagnetic ordering at TN = 9 K, as characterized by the appearance of distinct additional peaks in the neutron diffraction pattern below TN. Its magnetic reflections can be indexed with a propagation vector k = (0,0,0). The magnetic moments inside the FeO6-FeO5 clusters are ferromagnetic, whereas these clusters are antiferromagnetic along the chains. The adjacent chains are in turn ferromagnetically arranged along the a-axis. The magnetic structure of Li2FeP2O7 cathode material is described focusing on their localized spin-spin exchange. The magnetic structure and properties have been generalized for Li2FeP2O7-Li2CoP2O7 binary solid solutions.
Inorganic Chemistry 02/2013; · 4.60 Impact Factor
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Sho Hangai,
Fumihiko Nakamura,
Yasuhiko Kamikubo,
Motoshi Ichikawa,
Hirobumi Suzuki,
Shuntaro Yoshida, Atsuo Yamada,
Yutaka Takazawa,
Masashi Fukayama,
Kazuhiko Koike,
Mineo Kurokawa
Annals of Hematology 12/2012; · 2.62 Impact Factor
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ABSTRACT: The crystal and magnetic structure and properties of the Na(2)CoP(2)O(7) Na(+)-ion battery cathode material have been characterized by magnetic susceptibility, specific heat, and variable-temperature neutron powder diffraction measurements. Na(2)CoP(2)O(7) crystallizes in the orthorhombic space group Pna2(1) with a = 15.4061(3) Å, b = 10.28854(9) Å, and c = 7.70316(15) Å, having a layered structure with slabs of [CoP(2)O(7)](∞) separated by Na cations. The magnetic property measurements and neutron diffraction data analysis reveal that the material undergoes long-range ordering to a noncollinear antiferromagnetic G-type structure below T(N) ≈ 6.5 K. The magnetic structure is rationalized as a result of supersuperexchange between Co(2+) atoms linked by phosphate groups.
Inorganic Chemistry 12/2012; · 4.60 Impact Factor
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ABSTRACT: Ion-transport paths: Combined modeling and neutron diffraction studies provide atomic-scale insights into Li(2) FeP(2) O(7) , a material proposed for a new lithium-battery cathode with reversible electrode operation at the highest voltage of all known Fe-based phosphates. The results indicate that Li(+) ions are transported rapidly through a 2D network along the paths shown in green in the picture.
Angewandte Chemie International Edition 11/2012; · 13.45 Impact Factor
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ABSTRACT: OBJECTIVE: The efficacy of flexible spectral imaging color enhancement (FICE) on capsule endoscopy (CE) is unclear. The aim of this study was to estimate the efficacy of FICE on the detection on small intestinal diseases by CE. METHODS: We selected 6 patients without any diseases and 18 patients with following diseases; 4 tumors, 5 angioectasias, 7 ulcerative diseases, 1 ulcerative lesion and tumor and 1 ulcerative lesion and angioectasia. Three endoscopists reviewed all CE videos at standard and three types of FICE modes and compared sensitivity and specificity for detection on small intestinal diseases. RESULTS: Overall sensitivity of CE was 94.4% at standard mode, 90.7% at FICE ch. 1, 87.0% at FICE ch. 2, and 87.0% at FICE ch. 3 and overall specificity of CE was 66.7%, 55.6%, 77.8%, 66.7%, respectively in per-patient analysis. There was no significant difference between standard and each FICE mode. In per-lesion analysis, FICE ch. 1 detected more angioectasias as well as ulcerative lesions than standard mode (angioectasia, 25.7 vs 21.0, P = 0.005; ulcerative lesions, 19.3 vs 14.0, P = 0.06). However, FICE ch. 1 missed more tumors than S mode (4.3 vs 10.0, P = 0.003). CONCLUSIONS: Although detectability of FICE Ch. 1 is better on angioectasias or ulcerative lesions and worse on tumors or polyps compared with standard mode, patient-based sensitivity and specificity of small intestinal diseases are not different between standard and each FICE mode. Further experience and improvement of FICE are required.
Journal of Digestive Diseases 09/2012; · 1.59 Impact Factor
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ABSTRACT: The study was aimed to assess the efficacy of sodium phosphate (NaP) tablets and polyethylene glycol (PEG) on colon cleansing.
A prospective, randomized trial was conducted at the Graduate School of Medicine, University of Tokyo. Participants who were scheduled for colonoscopy were included and randomized into either the NaP or PEG group. An interim analysis was programmed into the study design when approximately 50% of the enrolments were completed. The primary outcome was the detection rate of polyps with a diameter ≤5 mm.
A total of 92 patients were included in the analysis, of whom 44 were in the NaP group and 48 in the PEG group. The quality of colonic preparation was similar in both groups. The NaP group showed a higher detection rate of polyps with a diameter ≤5 mm than the PEG group (38.6% vs 18.8%, P = 0.004). A multivariate analysis showed that NaP and the withdrawal time of the colonoscope were independent factors associated with the detection of polyps with a diameter ≤5 mm.
NaP is certainly not inferior to PEG. In fact, the results suggest that diminutive polyp detection using NaP might be superior to that using PEG.
Journal of Digestive Diseases 07/2012; 13(7):374-80. · 1.59 Impact Factor
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ABSTRACT: We have investigated polymorphs of LiFeSO(4)F, tavorite and triplite, which have been reported as cathode materials for lithium ion batteries. The predicted voltages are 3.64 and 3.90 V for tavorite and triplite, respectively, which agreed excellently with experimental data. It is found that the lithiated states (LiFeSO(4)F) of the polymorphs are almost degenerate in energy. The difference in voltage is mainly due to the difference in the stabilities of the delithiated states (FeSO(4)F). This is rationalized by the Fe(3+)-Fe(3+) repulsion in the edge sharing geometry of the triplite structure.
Physical Chemistry Chemical Physics 05/2012; · 3.57 Impact Factor
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ABSTRACT: We previously reported that hypertension is related to colonic diverticular bleeding, suggesting the involvement of arteriosclerosis. The recurrence of diverticular bleeding has been little investigated. We aimed to elucidate additional risk factors for diverticular bleeding and also to investigate the incidence rates and risk factors for re-bleeding.
Between January 2006 and September 2010, 62 patients with diverticular bleeding were admitted to our hospital. We then selected 124 control subjects with non-bleeding diverticula from the colonoscopy database of our department. Additionally, a retrospective cohort study was conducted using these case patients to estimate the re-bleeding rate after initial diverticular bleeding and the risk factors for re-bleeding. Odds ratios for diverticular bleeding were calculated by multivariate logistic regression in a case-control study. Cumulative re-bleeding rates since initial bleeding and hazard ratios of risk factors were estimated by Kaplan-Meier method and Cox proportional hazard model.
Sixty-two patients presented 99 bleeding episodes including the initial ones. Diabetes mellitus (OR 2.5, 95 % CI 1.2-5.2, P = 0.03), cardio- or cerebrovascular diseases (OR 4.2, 95 % CI 1.7-11.3, P = 0.003), and NSAID use (OR 3.7, 95 % CI 1.3-11.6, P = 0.02) were shown to be independent risk factors. The cumulative re-bleeding rates were 21 %, 34 %, and 40 % at 1, 2, and 3 years, respectively, in which NSAID use (HR 6.3, 95 % CI 1.7-20.7, P = 0.007) was a risk factor for re-bleeding.
Diabetes mellitus and vascular diseases were risk factors for diverticular bleeding, suggesting systemic metabolic disorders and arteriosclerosis might play an important role.
International Journal of Colorectal Disease 05/2012; 27(9):1161-6. · 2.38 Impact Factor
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Annals of Hematology 04/2012; 91(11):1819-20. · 2.62 Impact Factor
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ABSTRACT: Li-metal pyrophosphates have been recently reported as novel polyanionic cathode materials with competent electrochemical properties. The current study presents a detailed analysis of inherent electrochemical properties of mixed-metal pyrophosphates, Li2(Fe1–yMny)P2O7, synthesized by an optimized solid-state route. They form a complete solid solution assuming a monoclinic framework with space group P21/c. The electrochemical analysis of these single-phase pyrophosphates shows absence of activity associated with Mn, where near-theoretical redox activity associated with Fe metal center was realized around 3.5 V. We noticed a closer look revealed the gradual substitution of Mn into parent Li2FeP2O7 phase triggered a splitting of Fe3+/Fe2+ redox peak and partial upshifting in Fe3+/Fe2+ redox potentials nearing 4.0 V. Introduction of Mn into the pyrophosphate structure may stabilize the two distinct Fe3+/Fe2+ redox reactions by Fe ions in octahedral and trigonal-bipyramidal sites. Increase of the Gibb’s free energy at charged state by introducing Li+–Fe3+ and/or Li vacancy–Mn2+ pairs can be the root cause behind redox upshift. The underlying electrochemical behavior has been examined to assess these mixed-metal pyrophosphates for usage in Li-ion batteries.Keywords: lithium ion battery; cathode material; pyrophosphate; polyanion compounds
03/2012;
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ABSTRACT: Small bowel adenocarcinoma (SBA) has generally been considered to have a poor prognosis because of nonspecific presentations and difficulties in detection of the disease. The advent of capsule endoscopy (CE) and double-balloon endoscopy (DBE) makes it possible to access to the small intestine for endoscopic interventions. We describe a successful case of early jejunum adenocarcinoma completely resected by endoscopic mucosal resection (EMR) using double-balloon endoscopy (DBE). Early diagnosis and EMR using new technologies such as CE and DBE may improve the recognition of this disease that, at present, has a poor prognosis.
Diagnostic and Therapeutic Endoscopy 01/2012; 2012:521960.
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ABSTRACT: We aimed to investigate the association between colorectal polyp detection rates and withdrawal times, and also to investigate diverticulum detection rates as a counterpart lesion.
Thirteen trainee colonoscopists were characterized by their mean withdrawal time for normal colon. A total of 2,314 colonoscopies were analyzed.
The mean withdrawal times ranged from 6.5 to 10.4 minutes among colonoscopists. Polyp detection rates in individual endoscopists ranged between 36.5% and 60.0%. When stratified by the hood use, a significant association was shown when the hood was not used (p=0.03), whereas no association was found when the hood used. On the other hand, diverticulum detection rates varied from 20.7% to 43.2%. A strong association was shown only when the hood was not used (p=0.009).
An association between the polyp or diverticulum detection rate and the withdrawal time was observed when the transparent hood was not attached, and mainly on the right-side colon.
Hepato-gastroenterology 07/2011; 59(113):108-11. · 0.66 Impact Factor
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ABSTRACT: Capsule endoscopy (CE) for the stomach has not yet been in practical use. Likewise as in colon, CE for colorectal cancer screening, the less invasive nature of CE may be suitable for gastric screening. The aim of this study is to estimate a diagnostic yield of CE for gastric diseases.
This study involved 55 patients who participated in other clinical studies regarding obscure overt gastrointestinal bleeding or iron deficiency anemia. All patients underwent esophagogastroduodenoscopy and CE within 2 weeks. Sensitivity and specificity of CE for diffuse and localized gastric lesions were calculated, respectively.
Gastroscopy revealed 38 diffuse lesions (14 antral gastritis, 19 pangastritis, and 5 diffuse antral vascular ectasia) and 25 localized lesions (14 erosions, 2 cancers, and 9 polyps). CE had a higher sensitivity for gastric diffuse lesions compared with localized lesions. For diffuse lesions, sensitivity and specificity of CE were 70% and 82%, respectively. For localized lesions, sensitivity and specificity of CE were 28% and 63%, respectively. All cancers could not be detected by CE.
Currently, the diagnostic yield of CE for gastric diseases is not high enough for gastric screening. Additional improvements including preparations, position change, or the invention of new technologies are required.
Abdominal Imaging 07/2011; 37(1):29-34. · 1.73 Impact Factor
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ABSTRACT: Gastritis and intestinal metaplasia (IM) have long been known to be risk factors for and precursors of gastric cancer. We aimed to elucidate the association between gastric cancer risk and the distribution of precancerous lesions in the stomach by histological analyses.
We analyzed patients from whom two biopsy specimens (one from the antrum and one from the corpus) were obtained by upper gastrointestinal endoscopy. Specimens were assessed for Helicobacter pylori, IM, and neutrophil infiltration (NI). Patients were classified into three groups based on the presence of IM. Patients were also classified into four groups based on the presence of NI. The prevalence of gastric cancer was compared between groups.
A total of 1395 patients were analyzed. Of these, 54 had gastric cancer (34 intestinal and 20 diffuse type). A multivariate analysis showed that male sex and the distribution of IM were independent risk factors for intestinal-type cancer. Compared with patients without IM (n = 1005), the odds ratio (OR) for patients with IM in the antrum only (n = 240) was 2.34 (95% confidence interval: 1.08-4.96), and that for patients with IM in the corpus (n = 150) was 5.84 (2.92-11.8). However, NI was related to diffuse-type cancer. Compared with patients without NI (n = 899), the OR for patients with NI in the corpus only (n = 122) was 3.66 (1.02-12.2).
The histological pattern and distribution of gastric mucosal change assessed by two biopsy specimens were related to gastric cancer.
Journal of Gastroenterology and Hepatology 05/2011; 26(10):1570-5. · 2.87 Impact Factor
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Atsuo Yamada,
Hirotsugu Watabe,
Shuntaro Obi,
Takafumi Sugimoto,
Shintaro Kondo,
Miki Ohta,
Goichi Togo,
Keiji Ogura,
Yutaka Yamaji,
Makoto Okamoto,
Haruhiko Yoshida,
Takao Kawabe,
Kazuhiko Koike,
Masao Omata
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ABSTRACT: Patients with hepatocellular carcinoma (HCC) sometimes suffer from obscure gastrointestinal bleeding. Portal hypertension (PH), common in cirrhosis, induces esophagogastric varices. Because of the location, PH also may influence mucosal abnormalities in the small intestine. The objective of this study is to estimate the prevalence of small intestinal mucosal abnormalities in HCC patients using capsule endoscopy (CE).
We prospectively conducted CE in HCC patients, and analyzed the findings in relation to hepatic function, the number and size of HCC tumor and findings obtained by conventional endoscopy.
Thirty-six patients (aged 66.7 ± 7.5 years, 29 men) underwent CE. Abnormal findings in the small bowel were found in 16 patients (44%), angioectasias in eight patients (22%), erosions in five (14%), varices in four (11%), polyps in four (11%), and submucosal tumor in one (3%). The patients with angioectasia had a larger spleen index than the no abnormal lesions group (85.4 ± 15.8 vs 59.0 ± 24.4, P = 0.02). The former group had been more frequently treated for esophageal varices endoscopically (62% vs 15%, P = 0.02). Large HCC nodules seemed more common in the patients with angioectasia than subjects without abnormal lesions (38% vs 5%, P = 0.06). Small intestinal varices also seemed to have a positive association with large HCC. During the follow up after CE, one patient with small intestinal polyps suffered from obscure gastrointestinal bleeding.
CE revealed that HCC patients frequently have small intestinal mucosal lesions. In particular, small intestinal angioectasia, which may cause obscure gastrointestinal bleeding, seems to be associated with portal hypertension.
Digestive Endoscopy 04/2011; 23(2):124-9. · 1.19 Impact Factor
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ABSTRACT: Balloon endoscopy has been accepted as an effective tool for examining the small intestine. Two types of balloon endoscopy, single and double, are commercially available. The difference in performance between these 2 types of balloon endoscopy has not yet been elucidated.
To compare the yield of single-balloon endoscopy (SBE) and double-balloon endoscopy (DBE).
Single-center, randomized, controlled trial.
University hospital in Tokyo, Japan.
Patients with suspected small-bowel disease.
SBE and DBE.
Outcomes were the total enteroscopy rate, diagnostic yield, complication rate, and clinical outcomes. Analysis was done by intent to treat.
The study started in April 2008 and was terminated in April 2010 because of an obvious disadvantage for the SBE group. Thirty-eight patients were enrolled in the study; 18 patients were assigned to the SBE group and 20 to the DBE group. The total enteroscopy rate was 0% in the SBE group and 57.1% in the DBE group (P = .002). In terms of complications, the DBE group had 1 patient with Mallory-Weiss syndrome, and the SBE group had 1 patient with hyperamylasemia. There was no difference in the overall diagnosis rate between the SBE and DBE groups (61.1% vs 50.0%, P = .49). There was no difference in therapeutic outcome between the SBE and DBE groups (27.8% vs 35.0%, P = .63).
Relatively small number of study patients.
Total enteroscopy is more easily performed with DBE than with SBE.
Gastrointestinal endoscopy 01/2011; 73(4):734-9. · 6.71 Impact Factor
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ABSTRACT: Endoscopic retrograde cholangiopancreatography (ERCP) and associated procedures are difficult to perform in patients with surgically altered anatomy. Recently, balloon enteroscopy (BE) has made it easier to perform ERCP in these patients. However, BE-assisted ERCP is often technically demanding and time consuming.
Spiral enteroscopy (SE), which has recently been developed, is a novel method of using a rotating overtube to pleat small bowel onto the enteroscope, thus advancing it through the lumen. We review the mechanism and efficacy of SE, especially in ERCP of patients with surgically altered anatomy, and report on the first patient to undergo ERCP using SE in Japan.
Spiral enteroscopy-assisted ERCP seems to be feasible and safe in patients with surgically altered anatomy. Additionally, SE-assisted ERCP appears to be easier to perform than other methods previously described and allows stable positioning of the enteroscope in order to perform delicate therapeutic maneuvers.
SE for ERCP is expected to be at least as useful as balloon enteroscopy in patients with surgically altered anatomy.
Journal of hepato-biliary-pancreatic sciences. 11/2010; 18(3):375-9.
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ABSTRACT: A new pyrophosphate compound Li(2)FeP(2)O(7) was synthesized by a conventional solid-state reaction, and its crystal structure was determined. Its reversible electrode operation at ca. 3.5 V vs Li was identified with the capacity of a one-electron theoretical value of 110 mAh g(-1) even for ca. 1 μm particles without any special efforts such as nanosizing or carbon coating. Li(2)FeP(2)O(7) and its derivatives should provide a new platform for related lithium battery electrode research and could be potential competitors to commercial olivine LiFePO(4), which has been recognized as the most promising positive cathode for a lithium-ion battery system for large-scale applications, such as plug-in hybrid electric vehicles.
Journal of the American Chemical Society 10/2010; 132(39):13596-7. · 9.91 Impact Factor
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Takafumi Sugimoto,
Miki Ohta,
Tsuneo Ikenoue, Atsuo Yamada,
Motohisa Tada,
Mitsuhiro Fujishiro,
Keiji Ogura,
Yutaka Yamaji,
Makoto Okamoto,
Fumihiko Kanai,
Takao Kawabe,
Masao Omata
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ABSTRACT: Recent advances in colonoscopic techniques have resulted in more frequent detection of superficial-type colorectal tumors, that is, laterally spreading tumors (LSTs), although little is known about the characteristic clinical features and genetic alterations of LSTs. To elucidate the molecular characteristics of LSTs, genetic alterations in the KRAS, BRAF and PIK3CA genes and abnormal expression of the p53, beta-catenin and MYC proteins were analyzed using direct DNA sequencing and immunohistochemistry for 50 protruded-type tumors (Protruded), 35 granular-type LSTs (LST-G) and 19 nongranular-type LSTs (LST-NG). In addition, loss of heterozygosity (LOH) close to the adenomatous polyposis coli (APC) gene (5q21) was examined in these tumors. In univariate analyses, significant differences were noted in the percentages with KRAS mutations (Protruded, LST-G, LST-NG = 30.0%, 54.3%, 21.1%, respectively, p = 0.0156), nuclear accumulation of beta-catenin (Protruded, LST-G, LST-NG = 50.0%, 37.1%, 68.4%, respectively, p = 0.0267), expression of MYC (Protruded, LST-G, LST-NG = 26.0%, 17.1%, 42.1%, respectively, p = 0.0456) and LOH at the APC gene locus (Protruded, LST-G, LST-NG = 22.0%, 20.0%, 47.4%, respectively, p = 0.0302). Multivariate analysis demonstrated that the macroscopic subtype of LST was significantly associated with KRAS mutation (for LST-NG: odds ratio [OR] 0.23, 95% CI 0.06-0.90) and nuclear accumulation of beta-catenin (for LST-NG: OR 4.05, 95% CI 1.11-14.8). Our data revealed that the 2 subtypes of LST have different molecular characteristics, suggesting that 2 or more different molecular mechanisms result in colorectal tumors with a similar growth pattern.
International Journal of Cancer 10/2010; 127(7):1562-9. · 5.44 Impact Factor
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Advanced Materials 08/2010; 22(32):3583-7. · 13.88 Impact Factor
