Search for Boosted Dark Matter in COSINE-100

We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7  kg·yr exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4 MeV and considering the invisible decay mode. Furthermore, by comparing our results with a previous BDM search conducted by the Super-Kamionkande experiment, we found that the COSINE-100 detector has advantages in searching for low-mass dark matter. This analysis demonstrates the potential of the COSINE-100 detector to search for MeV electron recoil signals produced by the dark sector particle interactions.

Definitive Radiotherapy in Patients with Clinical T1N0M0 Esophageal Squamous Cell Carcinoma: A Multicenter Retrospective Study

PURPOSE/OBJECTIVE(S)

In this study, we aimed to assess the failure pattern and survival outcomes and to analyze the optimal treatment field of definitive RT for T1N0M0 esophageal squamous cell carcinoma (ESCC).

MATERIALS/METHODS

We performed a retrospective analysis in a multi-institutional cohort of patients with histologically confirmed T1N0M0 ESCC. We included patients who underwent RT with definitive aim from 2010 to 2019. Patterns of failure were demonstrated as in-field locoregional, out-field locoregional and distant metastasis. In the survival analysis, freedom from locoregional recurrence and their association with clinicopathologic risk factors were analyzed. We performed a propensity score matching in the cT1b patients to adjust for the heterogeneity of radiation technique, radiation dose and the use of concurrent chemotherapy.

RESULTS

A total of 168 patients were included with a median follow-up of 34.0 months, and there were 20 cT1a, 94 cT1b and 24 cT1x, (cT1, not otherwise specified) patients. The rates of all and locoregional failure were 26.9% and 23.1% for cT1a and 25.0% and 22.4% for cT1b patients. 10 (10.6%) patients experienced grade ≥ 3 adverse events. Among 116 cT1b patients, 69 patients received elective nodal irradiation (ENI) and 47 patients received involved field irradiation (IFI). After propensity score matching, the 3-year FFLRR rate was 84.5% (95% Confidence Interval, 71.0 - 92.1%). There was no significant difference between the ENI and IFI patients in FFLRR (Log-rank P = 0.831). In the multivariate analysis, the use of concurrent chemotherapy was the only factor marginally associated with FFLRR (Hazard ratio, 0.17; 95% CI, 0.02 - 1.13; P = 0.067).

CONCLUSION

cT1a patients who cannot receive endoscopic resection, showed similar rates of failure compared with cT1b patients, which questioned the accuracy of the staging and raised the need for through treatment such as chemoradiotherapy. In cT1b patients, IFI using dose of 50 to 60 Gy with concurrent chemotherapy could be a reasonable treatment option.

Evidence for X(3872)→J/ψπ^{+}π^{-} Produced in Single-Tag Two-Photon Interactions

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e^{+}e^{-}→e^{+}e^{-}J/ψπ^{+}π^{-}, using 825  fb^{-1} of data collected by the Belle detector operated at the KEKB e^{+}e^{-} collider. We observe three X(3872) candidates, where the expected background is 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for Γ[over ˜]_{γγ}B(X(3872)→J/ψπ^{+}π^{-}) assuming the Q^{2} dependence predicted by a cc[over ¯] meson model, where -Q^{2} is the invariant mass squared of the virtual photon. No X(3915)→J/ψπ^{+}π^{-} candidates are found.

Search for an Invisibly Decaying Z^{'} Boson at Belle II in e^{+}e^{-}→μ^{+}μ^{-}(e^{±}μ^{∓}) Plus Missing Energy Final States

Theories beyond the standard model often predict the existence of an additional neutral boson, the Z^{'}. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z^{'} in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'} and of a lepton-flavor-violating Z^{'} in e^{+}e^{-}→e^{±}μ^{∓}Z^{'}. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an L_{μ}-L_{τ} theory, into upper limits on the Z^{'} coupling constant at the level of 5×10^{-2}-1 for M_{Z^{'}}≤6  GeV/c^{2}.

Automatic segmentation of mitochondria and endolysosomes in volumetric electron microscopy data

Automatic segmentation of intracellular compartments is a powerful technique, which provides quantitative data about presence, spatial distribution, structure and consequently the function of cells. With the recent development of high throughput volumetric data acquisition techniques in electron microscopy (EM), manual segmentation is becoming a major bottleneck of the process. To aid the cell research, we propose a technique for automatic segmentation of mitochondria and endolysosomes obtained from urinary bladder urothelial cells by the dual beam EM technique. We present a novel publicly available volumetric EM dataset - the first of urothelial cells, evaluate several state-of-the-art segmentation methods on the new dataset and present a novel segmentation pipeline, which is based on supervised deep learning and includes mechanisms that reduce the impact of dependencies in the input data, artefacts and annotation errors. We show that our approach outperforms the compared methods on the proposed dataset.

Efficacy and safety of transarterial chemoembolisation with cone-beam CT in patients with hepatocellular carcinoma within the Milan criteria: a retrospective cohort study

AIM

To compare the therapeutic efficacy and safety of transarterial chemoembolisation (TACE) for hepatocellular carcinoma (HCC) within the Milan criteria with or without the use of cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Patients with HCC within the Milan criteria who underwent conventional angiography-guided TACE (Angio-TACE group: 58 patients from January 2010 to December 2011) were compared with those who underwent CBCT-guided TACE (CBCT-TACE group: 55 patients from January 2013 to December 2014). Local progression-free survival (LPFS), progression-free survival (PFS), and overall survival (OS) were compared. Adverse events after TACE were also investigated.

RESULTS

Baseline characteristics were balanced between the two groups. LPFS was significantly longer in the CBCT-TACE group than in the Angio-TACE group (median: not reached for 36 versus 19.2 months, respectively; Log-rank p=0.029). In multivariable Cox regression analysis, CBCT guidance had a significantly lower risk of local progression or death (adjusted hazard ratio: 0.585; 95% confidence interval, 0.344-0.995; p=0.048); however, there was no significant difference in PFS (3-year PFS: 15.9% versus 26.8%, respectively; p=0.122) or OS (3-year OS: 85% versus 88.2%, respectively; p=0.761) between the Angio-TACE and CBCT-TACE groups. Post-embolisation syndrome occurred significantly less frequently in the CBCT-TACE group (p=0.002).

CONCLUSION

CBCT-guided TACE could improve local tumour control for HCC within Milan criteria and showed fewer cases of post-embolisation syndrome.

V-RBNN Based Small Drone Detection in Augmented Datasets for 3D LADAR System

A common countermeasure to detect threatening drones is the electro-optical infrared (EO/IR) system. However, its performance is drastically reduced in conditions of complex background, saturation and light reflection. 3D laser sensor LiDAR is used to overcome the problems of 2D sensors like EO/IR, but it is not enough to detect small drones at a very long distance because of low laser energy and resolution. To solve this problem, A 3D LADAR sensor is under development. In this work, we study the detection methodology adequate to the LADAR sensor which can detect small drones at up to 2 km. First, a data augmentation method is proposed to generate a virtual target considering the laser beam and scanning characteristics, and to augment it with the actual LADAR sensor data for various kinds of tests before full hardware system developed. Second, a detection algorithm is proposed to detect drones using voxel-based background subtraction and variable radially bounded nearest neighbor (V-RBNN) method. The results show that 0.2 m L2 distance and 60% expected average overlap (EAO) indexes are satisfied for the required specification to detect 0.3 m size of small drones.

Risk of diabetes in viral hepatitis B or C patients compared to that in noninfected individuals in Korea, 2002-2013: A population-based cohort study

While the association between hepatitis C virus (HCV) infection and diabetes has been established, the relationship between hepatitis B virus (HBV) infection and diabetes remains unclear. Therefore, we compared the association between diabetes development in HBV, HCV and co-infected (HBV/HCV) patients to that in noninfected participants using population-based cohort data. We used the National Health Insurance Service-National Sample Cohort, which consists of 514 791 randomly selected persons among those who underwent health check-ups from 2002 to 2003 aged 40-79 years. Adults found to have HBV or HCV infection from 2002 to 2003, without a prior history of diabetes, were selected as subjects. Competing risk regression models were used to estimate cumulative incidence and hazards ratios (HRs) of diabetes development. The cumulative incidences, incidence densities and HRs of diabetes were highest in the co-infected group, followed by those in the HCV-, HBV- and noninfected groups. The 12-year cumulative incidences were as follows: 42.0% in HBV/HCV-, 32.9% in HCV-, 23.9% in HBV- and 18.3% in the noninfected groups. The incidence density per 1000 person-years was 55.0, 51.5, 38.2 and 28.2 for the HBV/HCV-, HCV-, HBV- and noninfected groups, respectively. The adjusted HRs for diabetes were 1.90, 1.68 and 1.41 for the HBV/HCV-, HCV- and HBV-infected groups, respectively. Our findings suggest that both HCV and HBV infections are associated with the development of diabetes; therefore, prevention of, screening for, and treatment of both may reduce the risk of diabetes in these patients.

Long-Term Amerlioration of Bilirubin Glucuronidation Defect in Gunn Rats by Transplanting Genetically Modified Immortalized Autologous Hepatocytes

Ex vivo gene therapy, in which hepatocytes are harvested from mutants, retrovirally transduced with a normal gene and transplanted back into the donor, has been used for correction of inherited metabolic defects of liver. Major drawbacks of this method include limited availability of autologous hepatocytes, inefficient retroviral transduction of primary hepatocytes, and the limited number of hepatocytes that can be transplanted safely. To obviate these problems, we transduced primary hepatocytes derived from inbred bilirubin–UDP–glucuronosyl–transferase (BUGT)-deficient Gunn rats by infection with a recombinant retrovirus expressing temperature-sensitive mutant SV40 large T antigen (tsT). The immortalized cells were then transduced with a second recombinant retrovirus expressing human B-UGT, and a clone expressing high levels of the enzyme was expanded by culturing at permissive temperature (33°C). At 37°C, tsT antigen was degraded and the cells expressed UGT activity toward bilirubin at a level approximately twice that present in normal rat liver homogenates. For seeding the cells into the liver bed, 1 × 107 cells were injected into the spleens of syngeneic Gunn rats five times at 10-day intervals. Excretion of bilirubin glucuronides in bile was demonstrated by HPLC analysis and serum bilirubin levels were reduced by 27 to 52% in 40 days after the first transplantation and remained so throughout the duration of the study (120 days). None of the transplanted Gunn rats or SCID mice transplanted with the immortalized cells developed tumors. © 1998 Elsevier Science Inc.

Prognostic relevance of lymph node status for patients with ampullary adenocarcinoma after radical resection followed by adjuvant treatment

PURPOSE

Attempts have been made to revise the nodal stage due to simplicity of current N staging system in ampullary adenocarcinoma. However, because of the disease rarity, there have only been a few studies assessing the prognostic impact of lymph node (LN) parameters.

METHODS

We retrospectively analyzed 120 patients who underwent radical resection followed by adjuvant chemoradiotherapy for ampullary adenocarcinoma. The effect of LN parameters (number of total harvest LNs, number of metastatic LN (MLN), lymph node ratio (LNR), and log odds of positive LNs (LODDS)) on overall survival (OS), locoregional relapse-free survival (LRFS) and distant metastasis-free survival were evaluated. Cutoff points of MLN, LNR and LODDs were determined using maximal χ² method.

RESULTS

Fifty-seven patients (48%) were staged as pN1 and their survival was not significantly decreased compared with pN0 patients. There was also no significant difference between patients with MLN 0 vs. 1. In univariate analyses, MLN (0-1 vs. ≥2), LNR (≤17% vs. >17%) and perineural invasion were common prognosticators for OS and LRFS. Distant metastasis-free survival was not influenced by LN status. In addition, multivariate analysis revealed that among the LN parameters, LNR was able to independently predict both OS and LRFS.

CONCLUSIONS

LNR performs better than other LN related parameters for predicting survival. After radical resection followed by adjuvant treatment, survival of patients with one positive LN does not seem to differ from patients without LN metastasis.

The impact of obesity on febrile urinary tract infection and renal scarring in children with vesicoureteral reflux

INTRODUCTION

It has become clear that obesity is associated with a variety of infectious diseases, including urinary tract infection (UTI) and renal scarring.

OBJECTIVE

The aim of this study was to evaluate the association between obesity and the degree of febrile UTI (fUTI) and renal scarring in children with vesicoureteral reflux (VUR), and to stratify the results into obesity subcategories.

STUDY DESIGN

A total of 186 patients were diagnosed with VUR between January 2002 and December 2008. This study retrospectively reviewed the medical records of 72 children with primary VUR who had recurrent fUTI (more than twice). Overweight or obese status of the patients aged <2 years was defined using weight-for-length (WFL) measurements. For 2-5 year old children, body mass index (BMI) percentile-for-age was used. They were divided into three groups as follows; standard (<85%), overweight (85-95%), and obese (≥95%). The following clinical variables were compared: age at diagnosis of primary VUR (months), sex, VUR grade, hydronephrosis grade, presence of renal scarring, surgical treatment, and degree of inflammation during fUTI.

RESULTS

In the overweight and obese groups, VUR was diagnosed at a young age (P = 0.05), the degree of renal scarring was more severe (P = 0.006), and serum white blood cell count, C-reactive protein, and erythrocyte sedimentation rate (ESR) levels were significantly higher (P < 0.001, P < 0.001, and P < 0.001, respectively). Abnormal focal dimercaptosuccinic acid (DMSA) defects were present in 25 of the 72 children (35%). Cortical defects occurred more frequently in children with obesity, and they were associated with a higher grade of reflux and serum ESR levels (P = 0.007, P = 0.042, and P = 0.021, respectively). Among these risk factors, high-grade VUR (OR = 9.93, 95% CI = 1.13-86.71), and being overweight and obese (OR = 5.26, 95% CI = 1.75-15.82) were associated with increased renal scarring. However, ESR was not associated with renal scarring (OR = 1.01, 95% CI = 0.95-1.07).

DISCUSSION

The relationships between obesity and UTI are controversial. Some studies have shown positive results; however, other studies have shown opposite results. The main limitations of this study were the retrospective data collection via electronic medical records, and the small number of subjects.

CONCLUSIONS

This study showed that obesity in patients with VUR has an effect on fUTI and renal scar formation. If the patients with VUR have obesity, close follow-up should be performed, and VUR patients should be started on a weight-loss program, which could reduce the number of patients with chronic kidney disease in the future.

First Observation of the Doubly Cabibbo-Suppressed Decay of a Charmed Baryon: Λ_{c}^{+}→pK^{+}π^{-}

We report the first observation of the decay Λ_{c}^{+}→pK^{+}π^{-} using a 980  fb^{-1} data sample collected by the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. This is the first observation of a doubly Cabibbo-suppressed decay of a charmed baryon. We measure the branching ratio of this decay with respect to its Cabibbo-favored counterpart to be B(Λ_{c}^{+}→pK^{+}π^{-})/B(Λ_{c}^{+}→pK^{-}π^{+})=(2.35±0.27±0.21)×10^{-3}, where the uncertainties are statistical and systematic, respectively.

Facile Synthesis of Iron Oxide/Graphene Nanocomposites Using Liquid Phase Plasma Method

Liquid phase plasma (LPP) method was applied, for the first time, to the impregnation of iron oxide nanoparticles onto graphene sheet. Iron oxide nanoparticles with the size of 50 nm were precipitated with uniform dispersion on the surface of graphene sheet. The amount of iron oxide nanoparticles precipitated on graphene sheets increased with increasing LPP process times. The XPS, Raman and EDX analyses showed that the iron oxide/graphene composites synthesized by the LPP process.

Application of Silver and Silver Oxide Nanoparticles Impregnated on Activated Carbon to the Degradation of Bromate

Silver and silver oxide nanoparticles were impregnated on the surface of powdered activated carbon (PAC) using a single-step liquid phase plasma (LPP) method. Spherical silver and silver oxide nanoparticles of 20 to 100 nm size were dipersed evenly on the surface of PAC. The impregnated PAC exhibited a higher activity for the decomposition of bromate than bare PAC. The XPS, Raman and EDX analyses showed that the Ag/PAC composites synthesized by the LPP process.

Cardiorespiratory Fitness and Metabolic Syndrome in Postmenopausal African-American Women

We examined the association of cardiorespiratory fitness with metabolic syndrome in overweight/obese postmenopausal African-American women. Pooled baseline data on 170 African-American women from 2 exercise trials were examined. Metabolic syndrome was defined as at least 3 of the following: abdominal obesity, glucose intolerance, hypertension, low high-density lipoprotein cholesterol (HDL-C), and high triglycerides. Cardiorespiratory fitness (VO2peak) was determined using the Bruce treadmill protocol and categorized as: Very Low (VLCRF<18 mL·kg(-1) min(-1)), Low (LCRF=18.0-220-22-22.0 mL·kg(-1) min(-1)), and Moderate (MCRF>22.0 mL·kg(-1) min(-1)). Associations of metabolic syndrome with cardiorespiratory fitness were analyzed using one-way ANOVA and linear regression. VO2peak was significantly lower in the VLCRF compared to the MCRF group. Lower cardiorespiratory fitness was associated with higher prevalence of metabolic syndrome, abdominal obesity, hypertriglyceridemia, and low HDL among overweight/obese postmenopausal African-American women. In fully adjusted models, higher waist circumference and triglycerides were associated with lower VO2peak levels (P<0.01) and higher HDL-C was associated with higher VO2peak levels (P=0.03). Overweight/obese postmenopausal African-American women with very low cardiorespiratory fitness are more likely to have metabolic syndrome, higher body mass index, and unhealthier levels of certain metabolic syndrome components than women with moderate cardiorespiratory fitness.

Population-based epidemiology of primary biliary cirrhosis in South Korea

BACKGROUND

As a rare disease, only a few population-based epidemiology studies of primary biliary cirrhosis (PBC) have been reported.

AIMS

To elucidate the nationwide prevalence, incidence, complications, fatality and direct medical costs of PBC in South Korea.

METHODS

The nationwide Health Insurance Review and Assessment Service claims data and Rare Intractable Disease registration data on PBC, identified with the International Classification of Diseases (ICD) 10 code of K74.3, were obtained from 2009 to 2013. Age- and gender-specific prevalence and incidence rates of PBC were calculated, and data on complications, comorbidities, prescribed drugs, therapeutic procedures and direct medical costs were analysed.

RESULTS

A total of 2824 patients over 20 years old with PBC were identified in 2009-2013 (female-to-male ratio 6.2, median age 57 years old). The average age- and sex-adjusted incidence from 2011 to 2013 was 8.57 per million per year, and the average age- and sex-adjusted prevalence from 2009 to 2013 was 47.50 per million population. About 10% of patients presented with complications such as ascites (10.3%), variceal bleeding (5.8%) and/or hepatocellular carcinoma (HCC) (1.3%). Liver transplantation was undertaken in 71 patients (2.5%) for 5 years. Case fatality was 2.2% and the transplantation-free survival was 95.4% for 5 years.

CONCLUSIONS

This is the first report on the nationwide epidemiology of primary biliary cirrhosis in South Korea, demonstrating lower incidence and prevalence rates than those of Western countries, but a considerable disease burden, representing at least 10% were complicated with decompensated cirrhosis or hepatocellular carcinoma requiring liver transplantation.

Accidental displacement of a dental implant into the submandibular space during explantation

Dental implants are reliable and widely used, but complications such as peri-implantitis occasionally necessitate their removal. Accidents during removal are similar to those that may occur during extraction, including displacement into another structure in the maxillofacial region. We present a rare case of accidental displacement into the submandibular space, which happened during an attempt to remove an implant.

Microporous carbon nanosheets with redox-active heteroatoms for pseudocapacitive charge storage

We report microporous carbon nanosheets containing numerous redox active heteroatoms fabricated from exfoliated waste coffee grounds by simple heating with KOH for pseudocapacitive charge storage. We found that various heteroatom combinations in carbonaceous materials can be a redox host for lithium ion storage. The bio-inspired nanomaterials had unique characteristics, showing superior electrochemical performances as cathode for asymmetric pseudocapacitors.

Low pulmonary function is related with a high risk of sarcopenia in community-dwelling older adults: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011

Sarcopenia is the age-related reduction of skeletal muscle mass in older individuals. Respiratory muscle strength may be related to skeletal muscle mass and, thus, the present study attempted to estimate the risk of sarcopenia relative to decreased pulmonary function. The present findings demonstrated that low pulmonary function was associated with low muscle mass in community-dwelling older adults.

INTRODUCTION

Lean body mass is related to pulmonary function in patients with chronic obstructive pulmonary disease (COPD). However, the relationship between muscle mass and pulmonary function in healthy older adults has yet to be clarified. Thus, the present study investigated the association of pulmonary function with muscle mass in an older community-dwelling Korean population.

METHODS

This study included 463 disease-free subjects over 65 years of age who underwent anthropometric measurements, laboratory tests, spirometry, and the estimation of appendicular skeletal muscle (ASM) mass in the 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES). Low muscle mass was defined as the value of ASM divided by height squared (ASM/height(2)) that was less than two standard deviations (SD) below the sex-specific mean of the young reference group.

RESULTS

Forced expiratory volume in 1 s (FEV1[L]) and forced vital capacity (FVC[L]) were positively correlated with ASM/height(2) in males (p < 0.001 and p = 0.001, respectively) but not in females (p = 0.360 and p = 0.779, respectively). A univariate logistic regression analysis revealed that males with low FEV1 or FVC were more likely to have low muscle mass (odds ratio [OR] = 3.11, 95% confidence interval [CI] 1.62-5.99 for FEV1; OR = 1.99, 95% CI 1.13-3.53 for FVC); similar results were found for females, but the significance was lower (OR = 11.37, 95% CI 0.97-132.91 for FEV1; OR = 7.31, 95% CI 1.25-42.74 for FVC). After adjusting for age, smoking, and moderate physical activity, a low FEV1 value was associated with low muscle mass in both males (OR = 2.90, 95% CI 1.50-5.63) and females (OR = 9.15, 95% CI 1.53-54.77).

CONCLUSIONS

Using nationally representative data from the 2008-2011 KNHANES, low pulmonary function was found to be associated with low muscle mass in community-dwelling older Korean adults.

Simultaneous determination of arbutin and its decomposed product hydroquinone in whitening creams using high-performance liquid chromatography with photodiode array detection: Effect of temperature and pH on decomposition

OBJECTIVE

Arbutin is an effective agent for the treatment of melanin disorders. Arbutin may be converted to hydroquinone under conditions of high temperature, ultraviolet (UV) radiation and dilute acid. The aim of the current study was to develop an analytical method to determine the levels of arbutin and hydroquinone in whitening cosmetic products using high-performance liquid chromatography with photodiode array detection (HPLC-DAD). In addition, we investigated the effects of high temperature and pH on the decomposition of arbutin.

METHODS

Samples extracted using two-step sonications were separated on a C18 column using a gradient mobile phase consisting of water and methanol. A 60-mm (40 μL) DAD cell was used to enhance the sensitivity of hydroquinone determination. Thermal decomposition of arbutin was evaluated at temperatures ranging from 60 to 120°C for 1-36 h.

RESULTS

The method showed good linearity (R(2) ≥ 0.9997), precision (relative standard deviation, RSD < 5%) and acceptable extraction recovery (90-102.6%). The limits of quantitation for arbutin and hydroquinone were 0.0085 and 0.0119 μg mL(-1) , respectively. One sample of 21 cosmetic products tested contained arbutin at a concentration 1.61 g 100 g(-1) cream and 0.12 g 100 g(-1) cream of hydroquinone. Arbutin (327.18 ppm) decomposed after 6 h at 120°C and produced 10.73 ppm of hydroquinone.

CONCLUSION

The developed method is simple to detect both arbutin and hydroquinone simultaneously in cosmetic products, at an adequate level of sensitivity. Notably, temperature and pH did not influence the decomposition of arbutin to hydroquinone in a 2% arbutin cream.

Decalcification of benthic foraminifera due to "Hebei Spirit" oil spill, Korea

In order to determine the effects on foraminifera due to spilled crude oil in the "Herbei Spirit" incident, a study of benthic foraminiferal assemblages was carried out on sediment samples collected from the Sogeunri tidal flat, Taean Peninsula, Korea. Breakages of the chambers in the Ammonia beccarii and Elphidium subincertum species of the Sogeunri tidal flat with a low pH (6.98 on average) were marked. These chamber breakages occurred in 71.6% of A. beccarii and are thought to be caused by decalcification due to the fall in pH resulting from the "Hebei Spirit" oil spill. The factors that affect breakage of the chamber in benthic foraminifera under low pH condition may be not only deto decalcification but also to exposure duration of substrata in the tidal flat spilled crude oil.

The relationship between pulmonary function and bone mineral density in healthy nonsmoking women: the Korean National Health and Nutrition Examination Survey (KNHANES) 2010

The aim of this study was to examine the association between pulmonary function and bone mineral density (BMD) in subjects who had never smoked. Pulmonary function was associated with BMD in premenopausal, but not postmenopausal, women.

INTRODUCTION

It has been reported that low bone mass is common in patients with pulmonary disorders such as chronic obstructive pulmonary disease. However, in healthy nonsmoking women, the relationship between bone mass and pulmonary function has yet to be clarified. The object of this study was to determine whether pulmonary function is related to BMD in healthy nonsmoking women based on menopausal status.

METHODS

This study was a cross-sectional study based on data obtained from the Korean National Health and Nutrition Examination Survey (KNHANES), a nationwide representative survey conducted by the Korean Ministry of Health and Welfare in 2010. This study included 456 subjects who had never smoked and analyzed data concerning pulmonary function and BMD.

RESULTS

Functional vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were correlated with BMD at lumbar spine, femur neck (FN), and total hip in premenopausal women (p = 0.030, p = 0.003, p = 0.019, respectively, for FVC; p = 0.015, p = 0.006, p = 0.059, respectively, for FEV1). However, FVC and FEV1 were only correlated with BMD at FN in postmenopausal women (p = 0.003 for FVC; p = 0.006 for FEV1). Body mass index (BMI), FVC, and FEV1 were significantly related with BMD at FN, even after adjusting for age and other confounding factors (β = 0.334, p < 0.001; β = 0.145, p = 0.017; and β = 0.129, p = 0.037, respectively) in premenopausal women. However, only age and BMI were correlated with BMD at FN (β = -0.268, p = 0.001 and β = 0.384, p > 0.001) in postmenopausal women after adjusting for confounding factors.

CONCLUSIONS

Pulmonary function, including FVC and FEV1 are associated with BMD at FN in healthy nonsmoking premenopausal women but not in postmenopausal women.

Microanatomy and ultrastructure of outer mantle epidermis of the cuttlefish, Sepia esculenta (Cephalopoda: Sepiidae)

This study describes the ultrastructural characteristics of external epidermis of mantle of Sepia esculenta using light and electron microscopy. The epidermis was thicker on the ventral surface than on the dorsal surface, with a higher secretory cell distribution on the ventral surface than on the dorsal surface. The epidermis was a single layer composed of epithelial cells, secretory cells, ciliated cells and neuroglial cells. Epithelial cells were columnar with well-developed microvilli on the free surface, and the microvilli were covered with glycocalyx. The epithelial cells were connected to the neighboring cells by tight junctions and membrane interdigitations of the apico-frontal surface. Well-developed microfilaments were arranged in a vertical direction in the cortical cytoplasm. The secretory cells were categorized into three types (A, B and C) in accordance with the light microscopical characteristics and ultrastructures of the secretory granules. The distribution of these cells was in the following order: Type A>Type B>Type C. SEM observation revealed that the secretory pore size of the Type A secretory cells was approximately 8.6 μm×12.2 μm. Cytoplasm displayed a red color as the result of Masson's trichrome stain and H-E stain, and contained polygonal granules of approximately 1.2 μm2 with a high electron density. The secretory pore size of the Type B secretory cells was approximately 10.1 μm×12.1 μm. As the results of AB-PAS (pH 2.5) and AF-AB (pH 2.5) reactions, the cytoplasm displayed a red color. The cells contained membrane bounded secretory granules with very low electron density. The secretory pore of the Type C secretory cells was circular shape, and approximately 5.5 μm×5.5 μm. Cytoplasm was found to be homogeneous under H-E stain and Masson's trichrome stain, and displayed a red color. As the result of AB-PAS (pH 2.5) reaction, the cytoplasm displayed a red color. The electron density of the secretory substance was the highest among the three types of secretory cells. The ciliated cells had a ciliary tuft on the free surface and were distributed throughout the mantle with the exception of the adhesive organs. Neuroglial cells were connected to the basal membrane, epithelial cells, secretory cells and nerve fibers through cytoplasmic process, and contained neurosecretory granules with high electron density within the cytoplasm.

Response of six neutron survey meters in mixed fields of fast and thermal neutrons

Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ∼9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ∼85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ∼50 % in the thermal neutron field.

Search for an H-dibaryon with a mass near 2mΛ in Υ(1S) and Υ(2S) decays

We report the results of a high-statistics search for H dibaryon production in inclusive Υ(1S) and Υ(2S) decays. No indication of an H dibaryon with a mass near the M(H)=2m(Λ) threshold is seen in either the H→Λpπ(-) or ΛΛ decay channels and 90% confidence level branching-fraction upper limits are set that are between one and two orders of magnitude below the measured branching fractions for inclusive Υ(1S) and Υ(2S) decays to antideuterons. Since Υ(1S,2S) decays produce flavor-SU(3)-symmetric final states, these results put stringent constraints on H dibaryon properties. The results are based on analyses of 102 million Υ(1S) and 158 million Υ(2S) events collected with the Belle detector at the KEKB e(+)e(-) collider.

New limits on interactions between weakly interacting massive particles and nucleons obtained with CsI(Tl) crystal detectors

New limits are presented on the cross section for weakly interacting massive particle (WIMP) nucleon scattering in the KIMS CsI(Tℓ) detector array at the Yangyang Underground Laboratory. The exposure used for these results is 24 524.3  kg·days. Nuclei recoiling from WIMP interactions are identified by a pulse shape discrimination method. A low energy background due to alpha emitters on the crystal surfaces is identified and taken into account in the analysis. The detected numbers of nuclear recoils are consistent with zero and 90% confidence level upper limits on the WIMP interaction rates are set for electron equivalent energies from 3 to 11 keV. The 90% upper limit of the nuclear recoil event rate for 3.6-5.8 keV corresponding to 2-4 keV in NaI(Tℓ) is 0.0098 counts/kg/keV/day, which is below the annual modulation amplitude reported by DAMA. This is incompatible with interpretations that enhance the modulation amplitude such as inelastic dark matter models. We establish the most stringent cross section limits on spin-dependent WIMP-proton elastic scattering for the WIMP masses greater than 20  GeV/c2.

Comparison between wild and hatchery populations of Korean pen shell (Atrina pectinata) using microsatellite DNA markers

Pen shell (Atrina pectinata) is a popular food source with a high commercial value in a number of Asian Pacific areas. The natural A. pectinata population has been declining continuously over the past several decades. Microsatellite DNA markers are a useful DNA-based tool for monitoring the genetic variation of pen shell populations. In this study, 20 polymorphic microsatellite (MS) DNA markers were identified from a partial genomic pen shell DNA library enriched in CA repeats, and used to compare allelic variation between wild and hatchery pen shell populations in Korea. A total of 438 alleles were detected at the 20 MS loci in the two populations. All loci were easily amplified and demonstrated allelic variability, with the number of alleles ranging from 5 to 35 in the wild population and from 5 to 22 in the farmed population. The average observed and expected heterozygosities were 0.69 and 0.82, respectively, in the hatchery samples and 0.69 and 0.83, respectively, in the wild samples. Statistical analysis of fixation index (F_ST) and analysis of molecular variance (AMOVA) showed minor, but significant, genetic differences between the wild and hatchery populations (F_ST = 0.0106, CI_95% = 0.003–0.017). These microsatellite loci may be valuable for future aquaculture and population genetic studies for developing conservation and management plans. Further studies with additional pen shell samples are needed to conclusively determine the genetic diversity between the wild and hatchery populations.

Fabrication of hemispherical nano structure on a curved Al surface using low-temperature and high-voltage anodizing method

A simple method of fabricating hemispherical nanostructures on a curved aluminum rod surface was presented. In conventional methods of fabricating nanopatterns on a curved aluminum surface, mechanical or chemical processes have been widely used for the lens technologies. Such processes are not only expensive with long processing times, however, but they also involve local fabrication and are limited in the dimension size. In this paper, a method of fabricating hemispherical nanostructures on a curved aluminum surface is suggested for a functional three-dimensional (3D) master using a low-temperature and high-voltage (LTHV) anodizing method. By reducing the aluminum reaction rate under a low-temperature environment, the reaction current density can be remarkably reduced even though a high voltage was induced. Using the LTHV anodizing method, the hemispherical pattern size can be easily controlled with respect to voltage variations. The sizes of the hemispherical nanopatterns were about 150-300 nm. Using the LTHV anodizing process, hemispherical nanostructures can be obtained on a curved aluminum surface with controllable pattern sizes of 150-300 nm without defects such as burring from Joule's heat, micro-scratches, and cracks. A curved 3D hemispherical nanostructure may be used as a master in the roll-to-roll process.

The Influence of Diabetes on the Relationship between N-terminal Pro-B-type Natriuretic Peptide and Body Mass Index

This study evaluated the influence of diabetes on the relationship between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and body mass index (BMI). Simultaneous NT-proBNP and echocardiographic Doppler examinations were performed in 1117 patients with dyspnoea undergoing cardiac catheterization. Patients were divided into BMI ≥ 25 kg/m2 (obese), 23 − 25 kg/m2 (overweight) and < 23 kg/m2 (non-obese) groups. In the 803 non-diabetic patients, mean plasma NT-proBNP levels in non-obese, overweight and obese patients showed a significant negative correlation with BMI (862.3 ± 228.8 pg/ml, 611.5 ± 149.7 pg/ml, 278.3 ± 172.5 pg/ml, respectively). In the 314 patients with diabetes, there was no correlation between BMI and NT-proBNP. This study demonstrated that obese patients had reduced concentrations of NT-proBNP compared with non-obese patients, despite having higher left ventricular filling pressures. NT-proBNP was not reduced in obese patients with diabetes. These results suggest that factors other than cardiac status impact on NT-proBNP concentration.

Control of Carbon and Electron Flow in Clostridium acetobutylicum Fermentations: Utilization of Carbon Monoxide to Inhibit Hydrogen Production and to Enhance Butanol Yields

Extracts prepared from non-solvent-producing cells of Clostridium acetobutylicum contained methyl viologen-linked hydrogenase activity (20 U/mg of protein at 37 degrees C) but did not display carbon monoxide dehydrogenase activity. CO addition readily inhibited the hydrogenase activity of cell extracts or of viable metabolizing cells. Increasing the partial pressure of CO (2 to 10%) in unshaken anaerobic culture tube headspaces significantly inhibited (90% inhibition at 10% CO) both growth and hydrogen production by C. acetobutylicum. Growth was not sensitive to low partial pressures of CO (i.e., up to 15%) in pH-controlled fermentors (pH 4.5) that were continuously gassed and mixed. CO addition dramatically altered the glucose fermentation balance of C. acetobutylicum by diverting carbon and electrons away from H(2), CO(2), acetate, and butyrate production and towards production of ethanol and butanol. The butanol concentration was increased from 65 to 106 mM and the butanol productivity (i.e., the ratio of butanol produced/total acids and solvents produced) was increased by 31% when glucose fermentations maintained at pH 4.5 were continuously gassed with 85% N(2)-15% CO versus N(2) alone. The results are discussed in terms of metabolic regulation of C. acetobutylicum saccharide fermentations to achieve maximal butanol or solvent yield.

Health behaviour and quality of life in Korean adults with respiratory disease: National Health Survey, 2005

OBJECTIVES

To describe disease management, health behaviour, psychological health and quality of life (QOL) in people with chronic respiratory disease (CRD).

METHODS

We analysed data from 798 adults with CRD drawn from the Korean National Health and Nutrition Examination Survey (KNHANES) 2005: 514 subjects with asthma alone, 258 with chronic obstructive pulmonary disease (COPD) alone, and 56 with asthma and COPD.

RESULTS

Disease management and health behaviour in this cohort were poor. One third of the cohort was not seeking any medical treatment, although many were currently experiencing respiratory symptoms. Twenty-six per cent of the subjects were current smokers who averaged 0.8 packs/day. More than half of the subjects did not exercise, only half of the subjects had regular health examinations and one third of the subjects did not get enough sleep. The study population exhibited poor psychological indices, functional health status and QOL. The combined asthma and COPD group was characterised by an increased frequency of problems related to functional status and QOL.

CONCLUSIONS

People with CRD are at high risk for functional limitations, unhealthy behaviour, poor mental status and poor QOL. A comprehensive disease management programme for people with CRD should be developed using collaborative team efforts.

The diagnostic value of the sagittal multiplanar reconstruction CT images for nasal bone fractures

AIM

To compare the diagnostic performance of sagittal multiplanar reconstruction (MPR) images and axial images for the detection of a nasal bone fracture.

MATERIALS AND METHODS

This prospective study included 533 consecutive patients who underwent three-dimensional images with 64-section multidetector-row CT for the evaluation of a facial bone fracture between June 2007 and May 2008 (366 males; 167 females; mean age +/- standard deviation 31.1+/-21.2 years; age range 1-92 years). Two observers independently scored the possibility of a nasal bone fracture on axial and sagittal images. Receiver operating characteristic (ROC) curve analysis was performed.

RESULTS

The Az values of the sagittal images were higher than those of the axial images for both observers (p=0.002 and 0.010, respectively) with higher accuracy (p<0.001 and 0.016, respectively). The sensitivities of sagittal images were superior to those of axial images, especially for type 1simple nasal bone fractures with no or minimal displacement (observer 1, 98.6 versus 72.8%; observer 2, 84.9 versus 71%).

CONCLUSION

Sagittal MPR facial bone CT images provided superior diagnostic performance, and their addition to axial images is useful for the evaluation of nasal bone fractures.

Complete blood count reflects the degree of oesophageal varices and liver fibrosis in virus-related chronic liver disease patients

To optimize management of chronic liver disease (CLD), a simple and noninvasive test to determine oesophageal varices (EV) and liver fibrosis is necessary. We performed a cohort study in a single tertiary care centre in order to devise a simple index reflecting EV and liver fibrosis. We derived an index reflecting EV which resulted from portal hypertension (the first part) and evaluated the index's ability to detect liver fibrosis which resulted in portal hypertension (the second part). Five hundred fifty-six patients (the first part, n = 409, mean age = 55.4 years, EV prevalence = 34.0%; the second part, n = 147, mean age = 48.8 years, cirrhosis prevalence = 12.9%) with virus-related CLD were included. P2/MS [(platelet count [10(9)/L])(2)/(monocyte fraction [%] x segmented neutrophil fraction [%])] was derived to detect EV. The area under the receiver-operating characteristic curve (AUROC) of P2/MS was 0.916 (95% confidence interval, 0.879-0.954) for detecting EV, and 0.905 (0.862-0.947) for detecting high-risk EV (grade >or= II or with red colour signs). P2/MS had AUROCs of 0.952 (0.904-0.999) and 0.873 (0.792-0.955) for histological cirrhosis (METAVIR F4) and significant fibrosis (METAVIR F2-F4), respectively, which were significantly greater than those of AST-to-platelet count ratio index (0.658, P < 0.001; 0.644, P = 0.003) and FIB-4 (0.776, P = 0.031; 0.707, P = 0.026). The predictive values of P2/MS were maintained at similar accuracy in subsequent validation sets. Our study suggests that P2/MS comprising only the complete blood count results is an efficient and noninvasive marker reflecting the presence of EV and the grade of liver fibrosis in patients with virus-related CLD. An independent external validation of P2/MS is required.

Enterococcus: not an innocent bystander in cirrhotic patients with spontaneous bacterial peritonitis

Clinicians sometimes experience treatment failure in the initial empirical antibiotics treatment using cephalosporins in cirrhotic patients with spontaneous bacterial peritonitis (SBP). Enterococcus, which is intrinsically resistant to cephalosporins, may be one of the causes of treatment failure. The aim of this study was to evaluate the clinical importance and the clinical characteristics of spontaneous enterococcal peritonitis (SEP). This was a retrospective cohort study of 359 patients with SBP treated in a single tertiary care center in South Korea from January 2000 through December 2004. We evaluated the clinical manifestation and the treatment results of SBP patients with enterococci identified from ascites culture. During the observation period, 13 of 359 patients (3.6%) diagnosed with culture-positive SBP had enterococcal peritonitis. For the initial empirical treatment, third-generation cephalosporins were administered to the 13 patients, ten of whom (76.9%) did not improve in the first 48 h. An in vitro antibiotic sensitivity test showed that the identified enterococci were susceptible to ampicillin plus gentamycin in eight patients (61.5%) and there was no vancomycin-resistant enterococcus. Although antibiotics were changed to antienterococcal antibiotics in 11 patients, only five patients improved. As a result, eight of the 13 patients (61.5%) with enterococcal SBP died during the observation period, and the one-month mortality was significantly higher from enterococcal SBP than from nonenterococcal SBP (P = 0.038). We conclude that enterococcal SBP has poor prognosis and it is reasonable to use antienterococcal antibiotics when enterococcus is identified from ascites culture of patients with liver cirrhosis.

Bacterial community structure, compartmentalization and activity in a microbial fuel cell

AIMS

To characterize bacterial populations and their activities within a microbial fuel cell (MFC), using cultivation-independent and cultivation approaches.

METHODS AND RESULTS

Electron microscopic observations showed that the fuel cell electrode had a microbial biofilm attached to its surface with loosely associated microbial clumps. Bacterial 16S rRNA gene libraries were constructed and analysed from each of four compartments within the fuel cell: the planktonic community; the membrane biofilm; bacterial clumps (BC) and the anode biofilm. Results showed that the bacterial community structure varied significantly between these compartments. It was observed that Gammaproteobacteria phylotypes were present at higher numbers within libraries from the BC and electrode biofilm compared with other parts of the fuel cell. Community structure of the MFC determined by analyses of bacterial 16S rRNA gene libraries and anaerobic cultivation showed excellent agreement with community profiles from denaturing gradient gel electrophoresis (DGGE) analysis.

CONCLUSIONS

Members of the family Enterobacteriaceae, such as Klebsiella sp. and Enterobacter sp. and other Gammaproteobacteria with Fe(III)-reducing and electrochemical activity had a significant potential for energy generation in this system.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has shown that electrochemically active bacteria can be enriched using an electrochemical fuel cell.

Determination of the neutron fluence spectra in the neutron therapy room of KIRAMS

High energy proton induced neutron fluence spectra were determined at the Korea Institute of Radiological and Medical Sciences (KIRAMS) using an extended Bonner Sphere (BS) set from the Korea Atomic Energy Research Institute (KAERI) in a series of measurements to quantify the neutron field. At the facility of the MC50 cyclotron of KIRAMS, two Be targets of different thicknesses, 1.0 and 10.5 mm, were bombarded by 35 and 45-MeV protons to produce six kinds of neutron fields, which were classified according to the measurement position and the use or no use of a beam collimator such as the gantry of the neutron therapy unit. In order to obtain a priori information to unfold the measured BS data the MCNPX code was used to calculate the neutron spectrum, and the influence of the surrounding materials for cooling the target assembly were also reviewed through this calculation. Some dosimetric quantities were determined by using the spectra determined in this measurement. Dose equivalent rates of these neutron fields ranged from 0.21 to 5.66 mSv h(-1)nA(-1) and the neutron yields for a thick Be target were 3.05 and 4.77% in the case of using a 35 and a 45-MeV proton, respectively.

Energy responses of the LiF series TL pellets to high-energy photons in the energy range from 1.25 to 21 MV

The energy responses for the KLT-300(LiF:Mg,Cu,Na,Si, Korea), GR-200(LiF:Mg,Cu,P, China) and MCP-N(LiF:Mg,Cu,P, Poland) thermoluminescence(TL) pellets were studied for a photon radiation with energies from 1.25 MeV(60Co) to 21 MV (Microtron) to verify the usefulness of the calibration for the radiotherapy beams. The International Atomic Energy Agency (IAEA) and the World Health Organization (WHO) have performed thermoluminescence dosimetry (TLD) audits to verify the calibration of the beams by TL powder, but TL pellets were used in this study because the element correction factor (ECF), defined as the factor to correct the variations that all TL dosemeters cannot be manufactured to have exactly the same TL efficiency, for each TL pellet could be accurately derived and be handled conveniently when compared with the powder. Also several works for the energy response of the TLDs were done for the low-energy photon beams up to 60Co, but they will be extended in this experiment to the high photon energies (up to 20 MV), which are widely used in the therapy level of a radiation. The PTW 30006 ionisation chamber was calibrated by the Korea primary standards to establish the air-kerma rates and the TL pellets were irradiated in a specially designed waterproof pellet holder in a water phantom (30 x 30 x 30 cm3) just like the IAEA postal audits programme. This result was compared with that of another type of phantom [10 (W) x 10 (L) x 10 (H) cm3 PMMA Perspex phantom for the 60Co and 6 MV photon, and 10 x 10 x 20 (H) cm3 for the 10 and 21 MV photon] for its convenient use and easy handling and installation in a hospital. The results show that the differences of the responses for the water phantom and PMMA Perspex phantom were negligible, which is contrary to the general conception that a big difference would be expected. For an application of these results to verify the therapy beams, an appropriate energy correction factor should be applied to the energies and phantom types in use.

Monte Carlo simulation of the photon beam characteristics from medical linear accelerators

The MCNPX code has been employed on a personal computer to calculate the dosimetric characteristics of the photon beams from the 6 MV Siemens MX2 and the 10 MV Varian Clinac 2100C linear accelerators. A model of the treatment head includes the major geometric structure within the beam path. The model was used to calculate the energy spectra of the photon beam, percentage depth dose and the dose profiles. The accuracy of the calculated results is examined by comparing them with the measured dose distributions for the two machines. The computed and measured depth dose curves agree to within 2% for all the depths beyond the build-up region for both treatment machines. The calculations agree to within 2% of the measured profiles within the 100-50% dose level. It has been found that the MCNPX code is an effective tool for simulating the clinical photon beam.

Dissimilatory Fe(III) reduction by an electrochemically active lactic acid bacterium phylogenetically related to Enterococcus gallinarum isolated from submerged soil

AIMS

The isolation and identification of a glucose-oxidizing Fe(III)-reducing bacteria (FRB) with electrochemical activity from an anoxic environment, and characterization of the role of Fe(III) in its metabolism.

METHODS AND RESULTS

A Gram-positive (Firmicutes), nonmotile, coccoid and facultative anaerobic FRB was isolated based on its ability to reduce Fe(III). Using the Vitek Gram-positive identification card kit and 16S rRNA gene sequence analysis, the isolate was identified as Enterococcus gallinarum, designated strain MG25. On glucose this isolate produced lactate plus small amounts of acetate, formate and CO2 and its growth rates were similar in the presence and absence of Fe(O)OH. These results suggest that MG25 can couple glucose oxidation to Fe(III) reduction, but without conservation of energy to support growth. Cyclic voltammetry showed that strain MG25 was electrochemically active.

CONCLUSIONS

An electrochemically active and FRB, E. gallinarum MG25, was isolated from submerged soil. Fe(III) is used in the bacterial metabolism as an electron sink.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report concerning the electrochemical activity of glucose-oxidizing FRB, E. gallinarum. This organism and others like it could be used as new biocatalysts to improve the performance of a mediator-less microbial fuel cell.

Mechanical and heat sensitization of cutaneous nociceptors in rats with experimental peripheral neuropathy

This study examined whether or not the properties of cutaneous nociceptive fibers are altered in the neuropathic state by comparing lumbars 5 and 6 spinal nerve ligation (SNL) rats with sham-operated controls. The rats with the unilateral SNL developed mechanical allodynia in the ipsilateral hind limb, whereas the sham group did not. Two to 5 weeks after the neuropathic or sham surgery, rats were subjected to single fiber-recording experiments to examine the properties of afferent fibers in the sural and plantar nerves. A total of 224 afferents in the C- and Adelta-ranges were characterized in the neuropathic and sham groups. Spontaneous activity was observed in 16 of 155 fibers in the neuropathic group and one of 69 fibers in the sham group. The response threshold of both the C- and Adelta-fibers to mechanical stimuli was lower in the neuropathic group than the sham group. The afferent fibers responsive to heat stimuli were all C-fibers, and none were Adelta-fibers. The response threshold of the C-fibers to the heat stimuli was lower in the neuropathic group than the sham group. The magnitude of the responses of both C- and Adelta-fibers to the suprathreshold intensity of the mechanical stimulus was greater in the neuropathic group than the sham group. However, the magnitude of the responses of C-fibers to the suprathreshold intensity of the heat stimulus in the neuropathic group was not different from that in the sham group. These results suggest that after a partial peripheral nerve injury, the nociceptors on the skin supplied by an uninjured nerve become sensitized to both mechanical and heat stimuli. This nociceptor sensitization can contribute to neuropathic pain.

Enrichment of microbial community generating electricity using a fuel-cell-type electrochemical cell

A fuel cell was used to enrich a microbial consortium generating electricity, using organic wastewater as the fuel. Within 30 days of enrichment the maximum current of 0.2 mA was generated with a resistance of 1 kOhms. Current generation was coupled to a fall in chemical oxygen demand from over 1,700 mg l(-1) down to 50 mg l(-1). Denaturing gradient gel electrophoresis showed a different microbial population in the enriched electrode from that in the sludge used as the inoculum. Electron microscopic observation showed a biofilm on the electrode surface and microbial clumps. Nanobacteria-like particles were present on the biofilm surface. Metabolic inhibitors and electron acceptors inhibited the current generation. 16S ribosomal RNA gene analysis showed a diverse bacterial population in the enrichment culture. These findings demonstrate that an electricity-generating microbial consortium can be enriched using a fuel cell and that the electrochemical activity is a form of anaerobic electron transfer.

Measurement of the neutron fluence and dose spectra using an extended bonner sphere and a tissue-equivalent proportional counter

A conventional Bonner Sphere (BS) set consisting of six polyethylene spheres was modified to enhance its response to a high-energy neutron by putting a lead shell inside a polyethylene moderator. The response matrix of an extended BS was calculated using the MCNPX code and calibrated using a 252Cf neutron source. In order to survey the unknown photon and neutron mixed field, a spherical tissue equivalent proportional counter (TEPC) was constructed and assembled as a portable measurement system. The extended BS and the self-constructed TEPC were employed to determine the dosimetric quantities of the neutron field produced from the thick lead target bombarded by the 2.5 GeV electron beam of Pohang Accelerator Laboratory (PAL) and the neutron calibration field of Korea Atomic Energy Research Institute (KAERI).

Culture conditions affect induction of vitellogenin synthesis by estradiol-17 beta in primary cultures of tilapia hepatocytes

In vitro synthesis of vitellogenin (VTG), a female-specific protein, after estradiol-17 beta (E(2)) treatment was compared among different culture conditions using the hepatocytes of tilapia, Oreochromis mossambicus. VTG was measured by enzyme-linked immunosorbent assay. Comparison of Leibovitz's L-15 medium (L-15), Williams' medium E (WE) and Medium 199 (M199), which have been used for hepatocyte cultures in certain teleost fishes, showed that monolayer formation of the hepatocytes on the plate in WE and M199 was faster than in L-15 at the beginning of the culture. Morphological differences in the hepatocytes among the culture media were not evident by 96 h after culture. VTG synthesis in L-15 after E(2) treatment was higher than in WE and M199. A concentration of NaHCO(3) at 5 mM in L-15 resulted in faster monolayer formation of the cells and higher VTG synthesis than at 0 and 23 mM. Primary culture of the tilapia hepatocytes at 28 degrees C showed higher synthesis of VTG than at 23 and 33 degrees C. These results suggest that nutritional requirements are vitally different among species, and there are optimal ranges in the pH and the temperature in cultured hepatocytes.

Effects of fish introduction on the length of the tail of cryptomonads in mesocosm experiments

Two different morphs of the small cryptomonad, Plagioselmis prolonga var. nordica with a posterior tail, were observed during summer and fall in the hypertrophic lake, Lake Kasumigaura, Japan. The tail shortened in mesocosms stocked with planktivorous silver carp ( Hypophthalmichthys molitrix Val.) and elongated by more than 50% in mesocosms from which silver carp were removed. The density of Plagioselmis cells increased significantly upon fish stocking and decreased upon fish removal. The tail length was negatively correlated with algal abundance and positively correlated with crustacean densities, but there was no correlation with nutrient levels or physical environmental parameters in the mesocosms. The variation in tail length was induced by the presence/absence of fish, but was not related to their density. However, silver carp manipulation strongly affected the density of the majority of zooplankters and, interestingly, there was a strong correlation between zooplankton density and tail-length change in Plagioselmis. We propose a possible herbivore-induced defense mechanism triggered by the top predator, silver carp.

Relativistic nonlinear Thomson scattering as attosecond x-ray source

Relativistic, nonlinear Thomson scattering by an electron of an intense laser field has been investigated by computer simulation. Under a laser field with a pulse duration of 20-fs full width at half maximum and an intensity of 10(20) W/cm(2), the motion of an electron is highly relativistic and generates an ultrashort radiation of 2 as with photon energies from 100 to 600 eV. An interesting modulated structure of the spectrum is observed and analyzed. A radiation produced by the zigzag motion of an electron under a linearly polarized laser has better characteristics than by a helical motion under a circularly polarized laser pulse in terms of an angular divergence and an energy spectrum. The effect of ion field in a plasma was also investigated, which shows that for a laser intensity of 10(20) W/cm(2), the ion field due to an ion density of up to 7 x 10(18) cm(-3) can be ignored during the laser pulse.