Search for η

We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}N→ηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2 nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}N→ηN process and/or a shallow η^{'}-nucleus potential.

Nonlinear association between bone mineral density and all-cause mortality: the Dong-gu study.

There was a U-shaped association between hip BMD and all-cause mortality, with the lowest mortality in the 90th percentile in males. However, there was an inverse linear relationship in females. In contrast, the association between lumbar spine BMD and mortality was less evident in males, with no association in females. INTRODUCTION: Bone mineral density (BMD) is reported inversely associated with mortality. Although some previous studies provided evidence for nonlinear associations, these were not adequately assessed in most previous works. METHODS: We evaluated the nonlinear relationship between BMD and mortality in Asians. Our study involved 8629 participants in the Dong-gu study from 2007 to 2010. Cox proportional hazard regression was used to calculate hazard ratios (HRs) according to BMD categories after adjusting for potential confounders. During a follow-up of 6.7 ± 1.4 years, 712 participants died. RESULTS: There was a U-shaped association between hip BMD and all-cause mortality, with the lowest mortality in the 90th percentile in males. However, there was an inverse linear relationship in females. In males, compared with the 75th to 95th percentile group, the < 2.5th percentile group had a 3.89 (95% CI 2.41-6.28)-fold higher risk and the 2.5th to 5th percentile group had a 2.51 (95% CI 1.25-5.04)-fold higher risk. The HR was 2.51 (95% CI 1.25, 5.04) in the > 97.5th percentile group. In females, compared with that in the 75th to 95th percentile group, the HR was 2.33 (95% CI 1.24, 4.39) in the < 2.5th percentile group. In contrast, the association between lumbar spine BMD and mortality was less evident in males, with no association in females. CONCLUSION: In conclusion, this study shows that the association between BMD and mortality varies by gender and that high and low BMD are predictors of all-cause mortality in males.

Differential Cross Section and Photon-Beam Asymmetry for the γ[over →]p → π

Differential cross sections and photon-beam asymmetries for the γ[over →]p→π^{-}Δ^{++}(1232) reaction have been measured for 0.7

NAD(P)H-quinone oxidoreductase 1 silencing aggravates hormone-induced prostatic hyperplasia in mice.

NAD(P)H-quinone oxidoreductase 1 (NQO1) is a highly inducible flavoprotein known to involve in various cellular defence mechanisms. In this study, we explored whether NQO1 deletion affects hormone-induced prostatic hyperplasia. Testosterone propionate (3 mg/kg, IP) was injected into wild-type (WT) and NOQ1 knockout C57BL/6 mice (NQO1-/- ) for 14 consecutive days, and the samples were collected for biological and histochemical studies. The testosterone-treated NQO1-/- showed about 140% higher prostate weight than the testosterone-treated WT, with enhanced connective tissue and hyperplastic glands formations. However, increased dihydrotestosterone level after testosterone treatment was not significantly different between the WT and NQO1-/- . In contrast, the enhanced nuclear expression of proliferating cell nuclear antigen in NQO1-/- prostate confirmed aggravated prostatic hyperplasia in NQO1-/- . Moreover, the expression of heat shock protein (HSP) 90-α was markedly increased in the NQO1-/- , and this was supported by increased testosterone-induced nuclear androgen receptor expression in NQO1-silenced LNCaP cells. Testosterone-induced prostate-specific antigen expression was not reversed in NOQ1-silenced cells after finasteride treatment. Although the exact role of NQO1 in prostatic hyperplasia remains unclear, the hyperplasia exacerbation due to NQO1 deletion might be independent of type 2 5α-reductase and might be related to enhanced androgen receptor affinity due to enhanced HSP90-α expression.

Interference Effect between ϕ and Λ(1520) Production Channels in the γp→K

The ϕ-Λ(1520) interference effect in the γp→K^{+}K^{-}p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between ϕ and Λ(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K^{+}K^{-} pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the sqrt[s]=2.1 GeV bump structure in forward differential cross sections for ϕ photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.

Comparison of outcomes after laparoscopy-assisted and open total gastrectomy for early gastric cancer.

BACKGROUND: The aim of this study was to compare the results of laparoscopy-assisted total gastrectomy with those of open total gastrectomy for early gastric cancer. METHODS: Patients with gastric cancer who underwent total gastrectomy with curative intent in three Korean tertiary hospitals between January 2003 and December 2010 were included in this multicentre, retrospective, propensity score-matched cohort study. Cox proportional hazards regression models were used to evaluate the association between operation method and survival. RESULTS: A total of 753 patients with early gastric cancer were included in the study. There were no significant differences in the matched cohort for overall survival (hazard ratio (HR) for laparoscopy-assisted versus open total gastrectomy 0.96, 95 per cent c.i. 0.57 to 1.65) or recurrence-free survival (HR 2.20, 0.51 to 9.52). The patterns of recurrence were no different between the two groups. The severity of complications, according to the Clavien-Dindo classification, was similar in both groups. The most common complications were anastomosis-related in the laparoscopy-assisted group (8.0 per cent versus 4.2 per cent in the open group; P = 0.015) and wound-related in the open group (1.6 versus 5.6 per cent respectively; P = 0.003). Postoperative death was more common in the laparoscopy-assisted group (1.6 versus 0.2 per cent; P = 0.045). CONCLUSION: Laparoscopy-assisted total gastrectomy for early gastric cancer is feasible in terms of long-term results, including survival and recurrence. However, a higher postoperative mortality rate and an increased risk of anastomotic leakage after laparoscopic-assisted total gastrectomy are of concern.

Intermediate-risk grouping of cervical cancer patients treated with radical hysterectomy: a Korean Gynecologic Oncology Group study.

BACKGROUND: In this study, we sought to identify a criterion for the intermediate-risk grouping of patients with cervical cancer who exhibit any intermediate-risk factor after radical hysterectomy. METHODS: In total, 2158 patients with pathologically proven stage IB-IIA cervical cancer with any intermediate-risk factor after radical hysterectomy were randomly assigned to two groups, a development group and a validation group, at a ratio of 3 : 1 (1620 patients:538 patients). To predict recurrence, multivariate models were developed using the development group. The ability of the models to discriminate between groups was validated using the log-rank test and receiver operating characteristic (ROC) analysis. RESULTS: Four factors (histology, tumour size, deep stromal invasion (DSI), and lymphovascular space involvement (LVSI)) were significantly associated with disease recurrence and included in the models. Among the nine possible combinations of the four variables, models consisting of any two of the four intermediate-risk factors (tumour size ≥3 cm, DSI of the outer third of the cervix, LVSI, and adenocarcinoma or adenosquamous carcinoma histology) demonstrated the best performance for predicting recurrence. CONCLUSION: This study identified a 'four-factor model' in which the presence of any two factors may be useful for predicting recurrence in patients with cervical cancer treated with radical hysterectomy.

Clinical characteristics of community-acquired acute pyelonephritis caused by ESBL-producing pathogens in South Korea.

OBJECTIVES: The aim of this study was to determine the risk factors and clinical characteristics of community-acquired acute pyelonephritis (CA-APN) caused by extended-spectrum ß-lactamase (ESBL)-producing organisms. METHODS: From March 2010 to February 2011, patients with CA-APN were recruited in 11 hospitals in South Korea. Clinical and microbiological data were collected prospectively, and the ESBLs and multilocus sequence types of the ESBL-producing Escherichia coli were characterized. Comparison between CA-APN caused by ESBL-producing Enterobacteriaceae and those by non-ESBL-producing organisms was performed. RESULTS: A total of 566 patients were recruited. Enterobacteriaceae were detected in 526 patients. Forty-six isolates (46/526, 8.7 %) were positive for ESBLs. Clinical and microbiological failure did not differ between the two groups, despite there being fewer patients with ESBL-positive isolates provided with appropriate antibiotics initially (19.6 vs. 93.8 %, p < 0.001). However, the duration of hospitalization was longer in the ESBL group (10.5 vs. 7.0 days, p = 0.012). In a logistic regression model, Charlson score ≥1 point [odds ratio (OR) 3.4, 95 % confidence interval (CI) 1.6-7.0, p = 0.001], antibiotics usage during the previous year (OR 3.1, 95 % CI 1.4-7.2, p = 0.008), and urinary catheterization during the previous month (OR 4.4, 95 % CI 1.1-17.6, p = 0.035) were associated with the risks of CA-APN by ESBL producers. CTX-M-15 (48 %) and CTX-M-14 (38 %) were the most common ESBLs. ST131 was the most common clone (7/24, 29.1 %), which was more frequently resistant to cefepime, fosfomycin, and temocillin. CONCLUSIONS: The risk factors for CA-APN by ESBL producers were Charlson score ≥1 point, antibiotics usage during the previous year, and urinary catheterization during the previous month.

Pancreaticoduodenectomy for advanced gastric carcinoma patients.

OBJECTIVE: The prognosis for patients with gastric carcinoma that has invaded adjacent organs, especially the pancreas, is very poor. We evaluated the survival of patients following pancreaticoduodenectomy (PD) and the survival benefit of intravenous chemotherapy in these patients. METHODS: We reviewed the hospital records of 16 gastric carcinoma patients who underwent PD during the period from 2001 to 2005. RESULTS: Half of the patients undergoing PD had Borrmann type III gastric carcinoma (8/16; 50%). Using Cox's proportional hazards regression model, only one factor was identified as an independent, statistically significant prognosticator intravenous chemotherapy (risk ratio, 0.054; 95% confidence interval, 0.01-0.45; p < 0.01). The 5-year survival rate was higher for patients who had intravenous chemotherapy than for patients who did not (22.2% vs. 0%; p < 0.01). CONCLUSION: The results highlight the improved survivorship of gastric carcinoma patients with PD who received intravenous chemotherapy compared with those who did not. We recommend resection in these patients and the administration of intravenous chemotherapy to improve their survival.

Spin-density matrix elements for γp→K*0Σ+ at Eγ=1.85-3.0 GeV with evidence for the κ(800) meson exchange.

The exclusive reaction γp→K(+)π(-)Σ(+) was measured for the first time using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. Angular distributions in the rest frame of the K(+)π(-) system were fitted to extract spin-density matrix elements of the K(*0) decay. The measured parity spin asymmetry shows that natural-parity exchange is dominant in this reaction. This result clearly indicates the need for t-channel exchange of the κ(800) scalar meson.

Fecal carriage of serotype K1 Klebsiella pneumoniae ST23 strains closely related to liver abscess isolates in Koreans living in Korea.

We determined the fecal carriage rate of serotype K1 Klebsiella pneumoniae in healthy Koreans and studied their genetic relationship with liver abscess isolates. We compared the carriage according to the country of residence. The stool specimens were collected through health promotion programs in Korea. K. pneumoniae strains were selected and tested for K1 by PCR. Serotype K1 isolates were characterized by multilocus sequence typing and pulsed field gel electrophoresis. A total of 248 K. pneumoniae isolates were obtained from 1,174 Koreans. Serotype K1 was identified in 57 (4.9%), of which 54 (94.7%) were ST 23 and were closely related to the liver abscess isolates. Participants aged >25 years showed a higher fecal carriage rate than those ≤ 25 (P = 0.007). The proportion of serotype K1 out of K. pneumoniae isolates in foreigners of Korean ethnicity who had lived in other countries was lower compared with those who had lived in Korea (5.6% vs 24.1%, P = 0.024). A substantial proportion of Koreans >25 years carries serotype K1 K. pneumoniae ST23 strains, which are closely related to liver abscess isolates. Differences in carriage rates by country of residence suggests that environmental factors might play an important role in the carriage of this strain.

Clinicopathologic features and prognosis of synchronous multiple gastric carcinomas.

OBJECTIVE: The study of synchronous multiple gastric carcinoma is of the utmost importance in the management of carcinoma of the gastric remnant and in the epidemiology and histogenesis of gastric carcinoma. We compared the clinicopathologic features and outcome of patients with synchronous multiple gastric carcinoma (SMGC) to those of patients with single gastric carcinoma. METHODS: Of the 3,320 patients diagnosed with gastric carcinoma who underwent surgery in our hospital, 188 patients (5.7%) were diagnosed with SMGCs. RESULTS: Early carcinomas were more frequently observed in patients with SMGCs than in patients with single gastric carcinoma (p < 0.001). In addition, lymph node metastasis was less common in patients with SMGCs than in patients with single gastric carcinomas (p < 0.05). Regarding the operative procedures, total gastrectomy was more frequently performed in patients with SMGC (32.5 vs. 20.2% ; p < 0.001). The 5-year survival rate of patients with SMGCs was higher than that of patients with single gastric carcinoma (69.3% vs. 54.1%, p < 0.001). Multivariate analysis showed that lymph node metastasis, serosal invasion, and curative resection were significant prognostic factors for the survival of patients with SMGCs. CONCLUSION: More recently, endoscopic or laparoscopic resection for early gastric carcinoma has frequently been performed. Careful preoperative and intraoperative evaluation and postoperative follow-ups are essential to detect any missed lesions in the remnant stomach, particularly in elderly patients with early gastric carcinoma.

Changing etiology of community-acquired bacterial meningitis in adults: a nationwide multicenter study in Korea.

Epidemiologic data on the etiologic organisms is important for appropriate empirical antibiotic treatment of bacterial meningitis. We identified the etiologies of community-acquired bacterial meningitis in Korean adults and the associated epidemiological factors. A retrospective, multicenter nationwide study was carried out. Patients 18 years of age or older with community-acquired bacterial meningitis with a confirmed pathogen were enrolled. Demographic, clinical, and microbiological data were collected. One hundred and ninety-five cases were collected. Streptococcus pneumoniae was the most common pathogen (50.8%), followed by Staphylococcus aureus (10.3%), Klebsiella pneumoniae (7.7%), Listeria monocytogenes (6.7%), and group B Streptococcus (3.1%). The penicillin resistance rate of the S. pneumoniae was 60.3%; 40.0% of the organisms were not susceptible to third-generation cephalosporins. The combination of third-generation cephalosporin with vancomycin was used in 76.3% of cases. Steroids were given before or with the first dose of antibiotics in 37.4% of patients. The 30-day mortality rate was 20.5% and neurological sequelae developed in 15.6% of cases. S. pneumoniae was the most common organism identified in community-acquired bacterial meningitis among Korean adults. S. aureus, K. pneumoniae, L. monocytogenes, and group B Streptococcus were also common. S. pneumoniae had high rates of resistance to penicillin and third-generation cephalosporins.

Mechanics of nanowire/nanotube in-surface buckling on elastomeric substrates.

A continuum mechanics theory is established for the in-surface buckling of one-dimensional nanomaterials on compliant substrates, such as silicon nanowires on elastomeric substrates observed in experiments. Simple analytical expressions are obtained for the buckling wavelength, amplitude and critical buckling strain in terms of the bending and tension stiffness of the nanomaterial and the substrate elastic properties. The analysis is applied to silicon nanowires, single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanotube bundles. For silicon nanowires, the measured buckling wavelength gives Young's modulus to be 140 GPa, which agrees well with the prior experimental studies. It is shown that the energy for in-surface buckling is lower than that for normal (out-of-surface) buckling, and is therefore energetically favorable.

Asarone inhibits adipogenesis and stimulates lipolysis in 3T3-L1 adipocytes.

Asarone is a molecule found in certain plants such as Acorus calamus, the root of which is used in traditional medicine to treat diabetes. We determined the molecular mechanism underlying the anti-diabetic activity of asarone. Treatment of asarone significantly inhibited the differentiation of 3T3-L1 preadipocytes through suppression of expression of the transcription factors, CCAAT/enhancer binding protein-alpha and peroxisome proliferator activated receptor-gamma, which activate adipogenesis. Intracellular triglyceride levels were reduced by asarone in a dose-dependent manner and asarone treatment stimulated the phosphorylation of hormone-sensitive lipase. Together, the present findings indicate that asarone inhibits adipogenesis by down-regulation of PPARgamma and C/EBPalpha and reduces lipid accumulation by stimulation of lipolysis through an increase in hormone-sensitive lipase activity.

Orientational relationships and atomic arrangements of GaN nanorods grown on Al2O3 (0001) substrates by using hydride vapor phase epitaxy.

Scanning electron microscopy (SEM) images and transmission electron microscopy (TEM) images showed that the one-dimensional GaN nanorods were formed on Al2O3 (0001) substrates by using hydride vapor phase epitaxy without a catalyst. Selected area electron diffraction (SAED) pattern and high-resolution TEM (HRTEM) results showed that GaN nanorods grown on Al2O3 (0001) substrates had crystalline wurzite structures and (0001) preferential orientation. The morphologies of GaN nanorods were affected by the flow rates of the source materials. The orientational relationships between the GaN nanorods and the Al2O3 substrates were (0001)GaN perpendicular (0001) Al2O3 and [0110]GaN perpendicular [1120] Al2O3. Cross-sectional and plan-view atomic arrangements of the fully relaxed interfacial region are described on the basis of the TEM, the SAED pattern, and the HRTEM results.

Prognostic significance of histological grade in clear-cell carcinoma of the ovary: a retrospective study of Korean Gynecologic Oncology Group.

BACKGROUND: This study was to investigate the prognostic significance of clinicopathologic characteristics in patients with clear-cell carcinoma (CCC) of the ovary. MATERIALS AND METHODS: Two hundred and one patients with CCC of the ovary were registered in the Korean Gynecologic Oncology Group. The Korean Gynecologic Pathology Study Group reviewed the pathological slides centrally, using a universal grading system. The prognostic significances of clinicopathologic factors were evaluated by multivariate analysis. RESULTS: Most of the patients were diagnosed at an early stage (stage I, 61.3%), and the overall 5-year survival rate was 57%. Early-stage disease showed a favorable prognosis, but advanced diseases showed poor prognosis. Stage of disease was the only significant prognostic factor on multivariate analysis (P < 0.001). However, universal grade and residual tumor also showed prognostic significance on the forward stepwise likelihood ratio test. There was no survival difference observed between patients treated with paclitaxel-based and those treated with platinum-based combination chemotherapy. CONCLUSIONS: The stage, residual tumor, and universal grade were significant prognostic factors in patients with CCC of the ovary. The universal grading system is applicable in determining prognosis of CCC of the ovary. Further clinical trials for optimal chemotherapy are in need.

Multicentre study of the safety of laparoscopic subtotal gastrectomy for gastric cancer in the elderly.

BACKGROUND: The aim of this study was to assess the safety and short-term value of laparoscopic gastrectomy in the elderly with gastric cancer compared with a younger cohort. METHODS: Data on all patients with gastric cancer undergoing laparoscopic gastrectomy at ten institutions in Korea between May 1998 and December 2005 were collected. Patients under the age of 45 years and those undergoing total gastrectomy, proximal gastrectomy and pylorus-preserving gastrectomy were excluded. An analysis of clinicopathological data for patients aged 45-69 years (average-age group) and those aged 70 years or more (elderly group) was undertaken. RESULTS: Co-morbidity was more common and postoperative hospital stay was longer in elderly patients. Pre-existing pulmonary and cardiovascular disease in the elderly contributed to respiratory dysfunction and intraperitoneal complications respectively. Tumour size and location, stage, methods of reconstruction and the number of combined operations were similar in the two groups. There were no significant differences in postoperative morbidity or mortality. CONCLUSION: Although elderly patients had greater co-morbidity, laparoscopic gastrectomy was a safe treatment for gastric cancer in this age group.

Association between levels of physical activity and poor self-rated health in Korean adults: The Third Korea National Health and Nutrition Examination Survey (KNHANES), 2005.

OBJECTIVE: To investigate the association between level of physical activity and poor self-rated health in Korean adults. STUDY DESIGN: A cross-sectional study was conducted on 7,800 adults aged > or =19 years who completed the Health Interview and the Health Behavior Surveys, issued during the Third National Health and Nutrition Examination Survey (2005). METHODS: The association between self-rated health and physical activity was tested using Chi-squared test. Multiple logistic regression analysis was used to calculate the odds ratios of poor self-rated health for different levels of physical activity after adjusting for physical and chronic medical conditions. RESULTS: The prevalence of poor self-rated health was significantly lower as the level of physical activity increased, and odds ratios for poor self-rated health were significantly lower for higher levels of physical activity after adjusting for age, marital status, educational status, smoking, alcohol consumption, and the number of physical impairments and chronic medical conditions. The association was similar in different age groups and among healthy respondents and respondents with physical impairments or chronic medical conditions. CONCLUSIONS: Physical activity was positively associated with self-rated health in Koreans. The independent association between a lower level of physical activity and poor self-rated health supports public health programmes that encourage regular physical activity.

Prognostic factors in FIGO stage IB-IIA small cell neuroendocrine carcinoma of the uterine cervix treated surgically: results of a multi-center retrospective Korean study.

BACKGROUND: To determine the clinical and pathologic prognostic factors in surgically treated patients with International Federation of Gynecology and Obstetrics (FIGO) stage IB-IIA small cell neuroendocrine carcinoma of the uterine cervix (SCNEC). PATIENTS AND METHODS: We retrospectively reviewed a total of 68 patients with FIGO stage IB-IIA SCNEC surgically treated from January 1997 to December 2003 in Korea. RESULTS: Of the 68 patients, 43 had FIGO stage IB1 SCNEC, 15 had stage IB2, and 10 had stage IIA. Seven were treated with radical surgery alone; 11 with neoadjuvant chemotherapy (NACT) followed by radical surgery; 24 with radical surgery followed by adjuvant chemotherapy; and 26 with radical surgery followed by adjuvant radiation or chemoradiation. After a median follow-up of 44 months (range, 6-113 months), the 2-year and 5-year survival rates for all patients were 64.6% and 46.6%, respectively. Univariate and multivariate analysis showed that FIGO stage was predictive of poor prognosis. Patients who received NACT showed poorer prognosis than those who did not receive NACT. Adjuvant chemoradiation did not improve survival compared with adjuvant chemotherapy alone. CONCLUSIONS: FIGO stage may act as a surrogate for factors prognostic of survival. Primary radical surgery followed by adjuvant chemotherapy is the preferred treatment modality for patients with early stage SCNEC.