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1.
Dis Esophagus ; 30(12): 1-7, 2017 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-28881892

RESUMEN

This study aims to assess the influence of esophagectomy with gastric transposition on the gastroesophageal reflux (GER) and gastric acidity in patients with esophageal cancer. Data on 53 esophageal cancer patients who underwent 24-hour impedance-pH monitoring after esophagectomy were retrospectively analyzed. We used a solid-state esophageal pH probe in which the esophageal pH sensor is placed 1.5 cm distal to the upper esophageal sphincter and the gastric pH sensor is located 15 cm distal to the esophageal pH channel. 24-hour impedance-pH monitoring data and other clinical data including anastomosis site stricture and incidence of pneumonia were collected. We defined pathologic reflux with reference to known normative data. Stricture was defined when an intervention such as bougienage or balloon dilatation was required to relieve dysphagia. The esophageal and gastric mean pH were 5.47 ± 1.51 and 3.33 ± 1.64, respectively. The percent time of acidic pH (<4) was 6.66 ± 12.49% in the esophagus and 70.53 ± 32.19% in the stomach. Esophageal pathologic acid reflux was noticed in 32.1%, 20.8%, and 35.8% during total, upright, and recumbent time, respectively. Esophageal pathologic bolus reflux was noted in 83.0%, 77.4%, and 64.2% during total, upright, and recumbent time, respectively. Gastric acidity increased with time after esophagectomy. Esophageal acid exposure time correlated with intragastric pH. However, esophageal pathologic acid reflux was not associated with anastomosis site stricture or pneumonia. In conclusion, GER frequently occurs after esophagectomy. Thus, strict lifestyle modifications and acid suppression would be necessary in patients following esophagectomy.


Asunto(s)
Neoplasias Esofágicas/cirugía , Esofagectomía/efectos adversos , Esofagoplastia/efectos adversos , Esófago/cirugía , Reflujo Gastroesofágico/etiología , Estómago/cirugía , Anciano , Anastomosis Quirúrgica/efectos adversos , Estenosis Esofágica/etiología , Monitorización del pH Esofágico , Femenino , Jugo Gástrico/química , Humanos , Concentración de Iones de Hidrógeno , Masculino , Persona de Mediana Edad , Neumonía por Aspiración/etiología , Postura , Estudios Retrospectivos , Factores de Riesgo
2.
Clin Radiol ; 72(8): 692.e9-692.e15, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28364952

RESUMEN

AIM: To evaluate the incidence of adverse events and associated factors after radiofrequency ablation (RFA) in patients with hepatocellular carcinoma within 30 days. MATERIALS AND METHODS: The early complications that occurred within 30 days after RFA at a single institution from January 2000 to July 2010 were reviewed in order to evaluate the morbidity, mortality, and risk factors associated with the complications. In total, 1,211 patients (845 men, 70.5%) with a mean age of 68 years (range, 27-88 years) underwent 1,843 RFA procedures. RESULTS: The overall incidence rate of complications was 6.8% (125 cases). Major complications (n=36, 2%) included liver abscess (n=15, 0.8%), intraperitoneal bleeding (n=8, 0.4%), liver failure (n=5, 0.3%), variceal bleeding (n=3, 0.2%), haemothorax (n=2, 0.1%), cholecystitis (n=2, 0.1%), and bowel perforation (n=1, 0.1%). Among the minor complications (n=89, 4.8%), the most common was the post RFA syndrome accompanied by pain and fever (n=75, 4.1%). Other minor complications included significant pleural effusion (n=7, 0.4%), skin wound infection (n=4, 0.2%), and thermal injuries to the skin (n=3, 0.2%). Procedural infections significantly increased with tumour size (OR=1.379; 95% confidence interval [CI], 1.191-1.579; p<0.001), and multiple overlapping ablations (OR=1.118; 95% CI, 1.019-1.227, p=0.018). Thrombocytopenia (<50,000/µl), prothrombin time, and serum albumin level were significantly associated with post-RFA bleeding episodes (p=0.041, p=0.021, and p=0.003, respectively). The overall mortality rate was 0.3% (three cases of hepatic failure, two case of sepsis, and one case of renal failure). CONCLUSIONS: RFA is a safe and effective local treatment for hepatocellular carcinoma. Careful selection of patients and appropriate RFA planning could decrease procedural mortality and morbidity.


Asunto(s)
Carcinoma Hepatocelular/cirugía , Ablación por Catéter/efectos adversos , Neoplasias Hepáticas/cirugía , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Factores de Tiempo , Adulto Joven
3.
Br J Radiol ; 88(1052): 20150156, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26055505

RESUMEN

OBJECTIVE: We evaluated tumour volume changes in patients with lung cancer undergoing concurrent chemoradiotherapy using image-guided radiotherapy (RT). METHODS: The kilovoltage image was obtained using CT on rail at every five fractions. The gross tumour volumes (GTVs), including the primary tumour and lymph nodes (LNs), were contoured to analyse the time and degree of tumour regression. RESULTS: 46 patients [32, non-small-cell lung cancer (NSCLC), and 14, small-cell lung cancer (SCLC)] were included in this study. In total, 281 CT scans and 82 sites of GTVs were evaluated. Significant volume changes occurred in both the NSCLC and SCLC groups (p < 0.001 and 0.002), and the average GTV change compared with baseline was 49.85 ± 3.65 [standard error (SE)]% and 65.95 ± 4.60 (SE)% for the NSCLC and SCLC groups, respectively. A significant difference in the degree of volume reduction between the primary tumour and LNs was observed in only the NSCLC group (p < 0.0001) but not in the SCLC group (p = 0.735). The greatest volume regression compared with the volume before the five fractions occurred between the 15 and 20 fractions in the NSCLC group and between the 5 and 10 fractions in the SCLC group. CONCLUSION: Both primary tumour and LNs were well defined using CT on rail. Significant volume changes occurred during RT, and there was a difference in volume reduction between the NSCLC and SCLC groups, regarding the degree and timing of the tumour reduction in the primary tumour and LNs. ADVANCES IN KNOWLEDGE: NSCLC and SCLC groups showed differences in the degree and timing of volume reduction. The primary tumour and LNs in NSCLC regressed differently.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/patología , Neoplasias Pulmonares/patología , Carcinoma Pulmonar de Células Pequeñas/patología , Anciano , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Carcinoma de Pulmón de Células no Pequeñas/terapia , Quimioradioterapia/métodos , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/terapia , Masculino , Persona de Mediana Edad , Radioterapia Guiada por Imagen/métodos , Carcinoma Pulmonar de Células Pequeñas/diagnóstico por imagen , Carcinoma Pulmonar de Células Pequeñas/terapia , Tomografía Computarizada por Rayos X/métodos , Carga Tumoral
4.
Appl Radiat Isot ; 101: 93-100, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25867108

RESUMEN

In this study, various techniques were attempted to investigate flow dynamics in the enclosed reactor and the results from the techniques were compared. Radioactive particle tracking (RPT) and industrial single photon emission computed tomography (SPECT) were carried out and the circulation times from them showed a deviation of 17.5%. The circulation time of the RPT was longer than that of SPECT, and it is speculated that the physical dimension of the/ fabricated radioactive particle creates the discrepancy. Particle image velocimetry (PIV) measurements and computational fluid dynamic (CFD) simulations were conducted. The velocity patterns from them were similar to each other in the entire reactor region except near the propeller installed at the bottom of the reactor.

5.
Indian J Nephrol ; 25(1): 57-9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25684875

RESUMEN

Due to their ability to decrease the spread of infection, hand sanitizers are now ubiquitous in health care settings. We present the case of a 50-year-old woman who was admitted with acute alcohol intoxication and had near complete recovery in 12 hrs. Subsequently, she was found unresponsive on the floor of her hospital room on two separate occasions. Evaluations revealed repeatedly elevated levels of ethanol, acetone, and lactate as well as increased anion gap and hypotension, requiring intensive care unit evaluation and intubation for airway protection. During the second episode, she was found next to an empty bottle of ethanol-based hospital hand sanitizer. She confirmed ingesting hand sanitizer in order to become intoxicated.

6.
Br J Cancer ; 108(10): 1978-84, 2013 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-23652310

RESUMEN

BACKGROUND: There have been controversies in prognostic impact of mucinous histology on colorectal cancer, and its implication in patients treated with adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is unclear. METHODS: Stage II and III colorectal cancer patients who underwent curative resection followed by adjuvant FOLFOX were included. Patients were grouped according to the mucinous content: >50%, mucinous adenocarcinoma (MAC); <50%, adenocarcinoma with intermediated mucinous component (AIM); and without any mucinous component, non-MAC (NMA). Clinicopathological features and disease-free survival (DFS) were compared. RESULTS: Among a total of 521 patients, 27 patients (5.2%) had MAC, 41 patients (7.9%) had AIM, and 453 patients (86.9%) had NMA. Mucinous adenocarcinoma and AIM had higher frequency of proximal location and microsatellite instability, but lower frequency of angiolymphatic invasion. Disease-free survival was significantly worse in the MAC compared with NMA (3-year DFS 57% and 86%, respectively; P<0.001) and AIM (3-year DFS 87%, P=0.01 vs MAC). Multivariate analysis revealed MAC as an independent negative prognostic factor of DFS (adjusted hazard ratio 7.96, 95% confidence interval 3.76-16.8). CONCLUSION: Adenocarcinoma with intermediated mucinous component and MAC have distinct clinicopathological features compared with NMA. Mucinous adenocarcinoma has an adverse prognostic impact on stage II or III colorectal cancer treated with adjuvant FOLFOX.


Asunto(s)
Adenocarcinoma Mucinoso/tratamiento farmacológico , Adenocarcinoma Mucinoso/patología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Adulto , Anciano , Anciano de 80 o más Años , Quimioterapia Adyuvante , Femenino , Fluorouracilo/uso terapéutico , Humanos , Leucovorina/uso terapéutico , Masculino , Persona de Mediana Edad , Mucinas/análisis , Mucinas/metabolismo , Estadificación de Neoplasias , Compuestos Organoplatinos/uso terapéutico , Pronóstico , Estudios Retrospectivos
7.
Br J Cancer ; 108(7): 1425-31, 2013 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-23481187

RESUMEN

BACKGROUND: We aimed to determine the role of palliative resection in metastatic colorectal cancer (mCRC) and ascertain which patient populations would benefit most from this treatment. METHODS: A total of 1015 patients diagnosed with mCRC at Seoul National University Hospital between 2000 and 2009 were retrospectively studied. RESULTS: Of the 1015 patients, 168 patients with only liver and/or lung metastasis received curative resection. The remaining 847 patients were treated with palliative chemotherapy and/or palliative resection combined with best supportive care. Palliative resection was performed in 527 (62.2%) cases (complete resection with negative margin (R0) in 93, R1/2 in 434). Resected patients had a more prolonged median overall survival (OS) than unresected patients (21.3 vs 14.1 months; P<0.001). In multivariate analysis, R0 resection was found to be associated with a superior OS compared with R1/2 resection (51.3 vs 19.1 months; P<0.001) and no resection (51.3 vs 14.1 months; P<0.001). When we performed propensity score matching, palliative resection was found to be related to prolonged OS (hazard ratio=0.72, 95% confidence interval=0.59-0.89; P=0.003). CONCLUSION: Palliative resection without residual disease and chemotherapy confers a longer-term survival outcome than palliative chemotherapy alone in mCRC patient subset.


Asunto(s)
Neoplasias Colorrectales/cirugía , Cuidados Paliativos/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Terapia Combinada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Pronóstico , Estudios Retrospectivos , Resultado del Tratamiento , Adulto Joven
8.
Apoptosis ; 16(9): 959-66, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21667042

RESUMEN

Chronic hepatitis C virus (HCV) infection is characterized by increased rates of apoptotic hepatocytes and activated caspases have been shown in HCV-infected patients. GS-9450, a novel caspase-inhibitor has demonstrated hepatoprotective activity in fibrosis/apoptosis animal models. This study evaluated the effects of GS-9450 on peripheral T-cell apoptosis in chronic HCV-infected patients. As sub study of the GS-US-227-0102, a double-blind, placebo-controlled phase 2a trial evaluating the safety and tolerability of GS-9450, apoptosis of peripheral CD4+ and CD8+ T-cells was measured using activated caspase-3, activated caspase-8 and CD95 (Fas). Blood samples were drawn at baseline, day 14 after therapy and at 5 weeks off-treatment follow-up in the first cohort of 10 mg. In contrast to the placebo-treated patients, GS-9450 caused a median of 46% decrease in ALT-values from baseline to day 14 in all treated patients (median of 118-64 U/l) rising again to a median of 140 U/l (19%) at 5 weeks off-treatment follow-up. In GS9450-treated patients, during treatment and follow-up, percentages of activated caspase-3+ and caspase-8 expression tended to decrease, in contrast to placebo-treated patients. Interestingly, compared to healthy controls, higher percentages of caspase-3 and caspase-8 positive CD4+ and CD8+ T-cells were demonstrated in HCV-infected patients at baseline. Decreased ALT-values were observed in all HCV-infected patients during treatment with low dose of the caspase-inhibitor GS-9450 accompanied by a lower expression of caspase-3 and -8 on peripheral T-cells. Furthermore, at baseline percentages of activated caspase-3, activated caspase-8 and CD95+ T-cells were higher in chronic HCV-infected patients compared to healthy controls.


Asunto(s)
Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD8-positivos/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 8/metabolismo , Inhibidores Enzimáticos/farmacología , Adulto , Apoptosis , Biomarcadores , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Activación Enzimática , Femenino , Citometría de Flujo , Estudios de Seguimiento , Hepacivirus/patogenicidad , Hepatitis C Crónica/sangre , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Carga Viral , Receptor fas/metabolismo
9.
J Phys Condens Matter ; 23(17): 175402, 2011 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-21493974

RESUMEN

This study examined the local structural properties of CuI at low temperatures of 10-300 K by x-ray diffraction (XRD) and extended x-ray absorption fine structure (EXAFS) measurements at the Cu K edge. The XRD data were refined using two models, split (distorted zinc-blende structure) and non-split (zinc-blende structure), using a conventional Rietveld refinement combined with a maximum entropy method (MEM). MEM/Rietveld analyses showed that both the split and non-split models could fit the data. EXAFS revealed the split model fit to be better than the non-split model. The split distance of Cu-I pairs was approximately 0.03 Å at 15 K and increased to 0.07 Å at 300 K. XRD and EXAFS combined together suggested that the CuI crystal was in a metastable state with a distorted zinc-blende structure at low temperatures.

10.
Gut ; 60(6): 799-805, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21242260

RESUMEN

BACKGROUND AND AIM: Colorectal cancer (CRC) is a multifactorial disease with both environmental and genetic factors contributing to its development. The incidence of CRC is increasing year by year in Japan. Patients with CRC in advanced stages have a poor prognosis, but detection of CRC at earlier stages can improve clinical outcome. Therefore, identification of epidemiologial factors that influence development of CRC would facilitate the prevention or early detection of disease. METHODS: To identify loci associated with CRC risk, we performed a genome-wide association study (GWAS) for CRC and sub-analyses by tumour location using 1583 Japanese CRC cases and 1898 controls. Subsequently, we conducted replication analyses using a total of 4809 CRC cases and 2973 controls including 225 Korean subjects with distal colon cancer and 377 controls. RESULTS: We identified a novel locus on 6q26-q27 region (rs7758229 in SLC22A3, p = 7.92 × 10⁻9, OR of 1.28) that was significantly associated with distal colon cancer. We also replicated the association between CRC and SNPs on 8q24 (rs6983267 and rs7837328, p = 1.51 × 10⁻8 and 7.44 × 10⁻8, ORs of 1.18 and 1.17, respectively). Moreover, we found cumulative effects of three genetic factors (rs7758229, rs6983267, and rs4939827 in SMAD7) and one environmental factor (alcohol drinking) which appear to increase CRC risk approximately twofold. CONCLUSIONS: We found a novel susceptible locus in SLC22A3 that contributes to the risk of distal colon cancer in an Asian population. These findings would further extend our understanding of the role of common genetic variants in the aetiology of CRC.


Asunto(s)
Cromosomas Humanos Par 6/genética , Neoplasias Colorrectales/genética , Adulto , Anciano , Estudios de Casos y Controles , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/patología , Femenino , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Genotipo , Humanos , Japón/epidemiología , Desequilibrio de Ligamiento , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple
11.
Nanotechnology ; 21(19): 195703, 2010 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-20407145

RESUMEN

Single-walled carbon nanotube (SWCNT) networks have become a subject of interest due to their ability to support structural, thermal and electrical loadings, but to date their application has been hindered due, in large part, to the inability to model macroscopic responses in an industrial product with any reasonable confidence. This paper seeks to address the relationship between macroscale electrical conductivity and the nanostructure of a dense network composed of SWCNTs and presents a uniquely formulated physics-based computational model for electrical conductivity predictions. The proposed model incorporates physics-based stochastic parameters for the individual nanotubes to construct the nanostructure such as: an experimentally obtained orientation distribution function, experimentally derived length and diameter distributions, and assumed distributions of chirality and registry of individual CNTs. Case studies are presented to investigate the relationship between macroscale conductivity and nanostructured variations in the bulk stochastic length, diameter and orientation distributions. Simulation results correspond nicely with those available in the literature for case studies of conductivity versus length and conductivity versus diameter. In addition, predictions for the increasing anisotropy of the bulk conductivity as a function of the tube orientation distribution are in reasonable agreement with our experimental results. Examples are presented to demonstrate the importance of incorporating various stochastic characteristics in bulk conductivity predictions. Finally, a design consideration for industrial applications is discussed based on localized network power emission considerations and may lend insight to the design engineer to better predict network failure under high current loading applications.

12.
Meat Sci ; 85(2): 368-72, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20374913

RESUMEN

This study compared effects of gamma ray (GR) and electron beam (EB) irradiation on quality (TBARS value, hardness, color), sensory characteristics, and total bacterial populations in beef sausage patties during accelerated storage at 30 degrees C for 10days. Beef sausage patties were vacuum-packaged and irradiated by GR and EB at 0, 5, 10, 15, and 20kGy at room temperature. The results of quality evaluation showed that the effects of GR irradiation were similar (p0.05) to EB irradiation on lipid oxidation, hardness, color and sensory scores of the beef sausage patties. However, GR-irradiated samples had lower (p<0.05) total bacterial counts than EB-irradiated samples after irradiation, and during storage regardless of irradiation dose. The results indicate that use of GR irradiation up to 10kGy on patties should be useful in reducing bacterial populations with no adverse effect on quality and most of sensory characteristics (color, chewiness, and taste).


Asunto(s)
Microbiología de Alimentos , Rayos gamma , Productos de la Carne/efectos de la radiación , Productos de la Carne/normas , Animales , Bacterias Aerobias/efectos de la radiación , Bovinos
13.
Clin Exp Dermatol ; 34(8): e594-6, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19583737

RESUMEN

Red-brown tattoos are usually treated with a frequency-doubled Q-switched (QS) neodymium:yttrium-aluminum-garnet Nd:YAG laser (532 nm), because red and pink pigments show maximum absorption between 500 and 570 nm. Using a QS laser for red-brown tattoo removal has sometimes led to paradoxical darkening of the tattoo pigments, and this darkened grey-black colour may be difficult to remove. A woman with red-brown cosmetic tattoos on her eyebrows was treated using a QS Nd:YAG laser (1064 nm) initially with low fluence and subsequently with increasing fluences at 6-weekly intervals. After the first treatment, a slight darkening of the tattoo pigments was seen, but this faded and complete clearance was achieved after five treatments. There was no downtime during every treatment and there were no scars, pigmentary alterations or textural changes.


Asunto(s)
Aluminio/uso terapéutico , Rayos Láser , Terapia por Luz de Baja Intensidad/métodos , Tatuaje/efectos adversos , Itrio/uso terapéutico , Adulto , Colorantes , Cejas , Femenino , Humanos , Resultado del Tratamiento
14.
Cell Mol Life Sci ; 66(2): 350-64, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19137262

RESUMEN

Comparative analysis of proteomes using 5-fluorouracil (5-FU)-resistant human colon cancer cell line revealed that decreased galectin-3 expression was significantly associated with retarded proliferation. However, in the presence of 5-FU proliferation rate of cells with suppressed galectin-3 expression did not differ from that of cells with normal galectin-3 expression, even galectin-3 suppression augmented apoptosis. Mechanism by which galectin-3 regulates cancer cell proliferation has been identified in immunoprecipitates of the anti-galectin-3 antibody. Heterogeneous nuclear ribonucleoprotein Q (hnRNP Q) was identified as a protein interacting with galectin-3. Interestingly, while galectin-3 protein was not affected by the hnRNP Q level, its suppression was accompanied by a decrease in hnRNP Q expression. The present study demonstrates that galectin-3 stabilizes hnRNP Q via complex formation, and reduction in the hnRNP Q level leads to slow proliferation and less susceptibility to 5-FU.


Asunto(s)
Proliferación Celular , Neoplasias del Colon/metabolismo , Galectina 3/metabolismo , Ribonucleoproteínas Nucleares Heterogéneas/metabolismo , Isoformas de Proteínas/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Secuencia de Aminoácidos , Antimetabolitos/metabolismo , Apoptosis/fisiología , Proteínas de Ciclo Celular , Línea Celular Tumoral , Neoplasias del Colon/patología , Regulación hacia Abajo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Fluorouracilo/metabolismo , Galectina 3/genética , Ribonucleoproteínas Nucleares Heterogéneas/genética , Humanos , Datos de Secuencia Molecular , Fosfoproteínas/metabolismo , Isoformas de Proteínas/genética , Proteínas Quinasas/metabolismo , Proteoma/análisis , Proteínas Quinasas S6 Ribosómicas/metabolismo , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR
16.
J Dent Res ; 87(9): 829-33, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18719208

RESUMEN

Water is ubiquitous in the mouths of healthy individuals and routinely interferes with efforts to bond restorations to dental tissues. Our previous studies using tapping-mode atomic force microscopy (TMAFM) have shown that nanophase separation is a general feature of cross-linked polymethacrylates photocured in the presence of water. To explore the relationship between nanophase separation in dentin adhesives and their long-term mechanical properties, we evaluated model adhesives after 3 months of aqueous storage. The degree of contrast in the TMAFM phase image depended on the formulations used, ranging from 'not observable' to 'very strong'. Correspondingly, the mechanical properties of these model adhesives varied from 'minimal change' to 'significant depreciation'. The results support the hypothesis that a high degree of heterogeneity at the nano-scale is associated with poor mechanical durability in these model adhesives.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios/química , Dentina/ultraestructura , Nanoestructuras/ultraestructura , Bisfenol A Glicidil Metacrilato/química , Fracaso de la Restauración Dental , Análisis del Estrés Dental , Dentina/efectos de los fármacos , Ensayo de Materiales , Metacrilatos/química , Microscopía de Fuerza Atómica , Estrés Mecánico , Tiempo , Agua/química
18.
Nature ; 451(7180): 805-8, 2008 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-18273014

RESUMEN

The motion of atoms in a solid always responds to cooling or heating in a way that is consistent with the symmetry of the given space group of the solid to which they belong. When the atoms move, the electronic structure of the solid changes, leading to different physical properties. Therefore, the determination of where atoms are and what atoms do is a cornerstone of modern solid-state physics. However, experimental observations of atomic displacements measured as a function of temperature are very rare, because those displacements are, in almost all cases, exceedingly small. Here we show, using a combination of diffraction techniques, that the hexagonal manganites RMnO3 (where R is a rare-earth element) undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling. We follow the exact atomic displacements of all the atoms in the unit cell as a function of temperature and find consistency with theoretical predictions based on group theories. We argue that this gigantic magneto-elastic coupling in RMnO3 holds the key to the recently observed magneto-electric phenomenon in this intriguing class of materials.

19.
Int J Colorectal Dis ; 23(1): 61-5, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17724601

RESUMEN

BACKGROUND AND AIMS: Colorectal cancer has been reported to be the malignancy most frequently associated with gastric cancer in Korea. The aim of this study was to define the frequency and clinical characteristics of synchronous gastric cancer detected at preoperative esophagogastroduodenoscopy (EGD) in colorectal cancer patients. MATERIALS AND METHODS: This prospective study analyzed the EGD results from 1,542 consecutive colorectal cancer patients who underwent surgery from January 2003 to December 2005 at the Center for Colorectal Cancer, National Cancer Center, Korea. RESULTS: Of the 1,542 cases, 1,155 (74.9%) underwent EGD at our center and 387 underwent EGD at other hospitals within 6 months before surgery. Of the 1,542 cases, synchronous gastric cancers were detected in 31 cases (2.0%). Of these 31 cases, 26 had early gastric cancer (EGC; 83.9%) and 5 had advanced gastric cancer. Ten (38.5%) of the 26 EGC cases were managed using endoscopic mucosal resection. Compared to colorectal cancer patients without synchronous gastric cancer, the group of patients with synchronous gastric cancer was older (65.5+/-9.6 vs 58.4+/-11.3 years, p=0.001) and had a greater proportion of males (77.4 vs 59.4%, p=0.043). CONCLUSION: This study found that 2% of Korean sporadic colorectal cancer patients had synchronous gastric cancer. A preoperative EGD for colorectal cancer patients is likely to greatly assist in the diagnosis of synchronous gastric cancer at an early stage and the implementation of appropriate minimally invasive treatment.


Asunto(s)
Neoplasias Colorrectales/patología , Endoscopía del Sistema Digestivo , Neoplasias Primarias Múltiples/patología , Neoplasias Gástricas/patología , Anciano , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/cirugía , Detección Precoz del Cáncer , Femenino , Gastrectomía , Humanos , Corea (Geográfico)/epidemiología , Masculino , Persona de Mediana Edad , Neoplasias Primarias Múltiples/epidemiología , Neoplasias Primarias Múltiples/cirugía , Estudios Prospectivos , Neoplasias Gástricas/epidemiología , Neoplasias Gástricas/cirugía
20.
Phys Rev Lett ; 99(7): 076401, 2007 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-17930908

RESUMEN

X-ray and neutron scattering studies were performed on DyB4 which exhibits both a quadrupolar ordering and a macroscopic lattice distortion. A forbidden reflection at 7.792 keV near the Dy L3 absorption edge is identified as a quadrupolar ordering peak, and the quadrupolar order and a monoclinic structural distortion develop concomitantly below 12.3 K as second-order-type phase transitions. Coupling between the quadrupolar order and the strain in DyB4 is directly demonstrated by observing that both order parameters are proportional to each other.

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