Duodenal switch without versus with laparoscopic cholecystectomy: a perioperative risk comparative analysis of the MBSAQIP database (2015-2019)

BACKGROUND

The results of concurrent cholecystectomy with Roux-en Y gastric bypass and sleeve gastrectomy have been well elucidated. Large-scale data on the outcomes of concomitant cholecystectomy during biliopancreatic diversion with duodenal switch (BPD-DS) are still lacking. Our study aimed to explore whether simultaneous cholecystectomy with BPD-DS alters the 30-day postoperative outcomes.

METHODS

We conducted a retrospective analysis of the MBSAQIP database between 2015 and 2019. Propensity-score matching (PSM) in BPD-DS with cholecystectomy (Group 1) and BPD-DS without cholecystectomy (Group 2) cohorts was performed (PSM ratio 1:2). The two groups were matched for a total of 21 baseline variables including age, gender, BMI, ASA class, and other medical comorbidities and conditions. The 30-day postoperative morbidity, mortality, reoperation, reintervention, and readmissions were obtained.

RESULTS

Initially, 568 patients in Group 1 and 5079 in Group 2 were identified. After performing PSM, 564 and 1128 patients respectively were compared. The BPD-DS with cholecystectomy group reported a higher rate of reoperation and reintervention compared to BPD-DS alone (3.9% versus 2.4% and 3.2% versus 2%, respectively), even though it did not reach statistical significance. The intervention time was significantly higher in Group 1 compared to Group 2 (192.4 ± 77.6 versus 126.4 ± 61.4 min). Clavien-Dindo complications (1-5) were similar between these two PSM cohorts.

CONCLUSION

Concomitant cholecystectomy during BPD-DS increases operative times but does not affect the other outcomes. Based on our results, the decision of cholecystectomy at the time of BPD-DS should be left to the surgeon's judgment.

IBCOx-17 Safety of Single Stage Revision Laparoscopic Sleeve Gastrectomy Compared to Laparoscopic Roux-Y Gastric Bypass After Failed Gastric Banding

Background

Reoperation, after failed gastric banding, is a controversial topic. A common approach is band removal with conversion to gastric bypass or sleeve gastrectomy in a single-step procedure. In 2017 the analysis of MBSQAIP Participant User File (PUF) from 2015 revealed that conversion to sleeve gastrectomy might be a safer approach when compared to gastric bypass surgery. We decided to utilize MBSAQIP data from 2015-2018 and replicate the study, addressing critical methodological flaws. This study aimed to assess the safety of revisional surgery to laparoscopic sleeve gastrectomy (LSG) compared to laparoscopic Roux-Y gastric bypass (LRYGB) after failed laparoscopic adjustable gastric banding (LAGB) based on MBSAQIP Participant User File from 2015 to 2018.

Methods

Patients who underwent a one-stage conversion of LAGB to LSG (Conv-LSG) or LRYGB (Conv-LRYGB) were identified in the MBSAQIP PUF from 2015 to 2017. Conv-LRYGB cases were matched (1:1) with Conv-LSG patients using propensity scoring to control for potential confounding. The primary outcome was all-cause mortality. Secondary outcomes were readmission, reoperation, intervention, leak and bleed rates, and morbidity.

Results

A total of 9 974 patients (4987 matched pairs) were included in the study. The groups were closely matched as intended. was associated with higher risk for readmission Conv-LRYGB, as compared with conv-SG, was associated with a similar risk of mortality (0.02% vs. 0.02%; relative risk [RR], 0.33; 95% confidence interval [CI], 0.03 to 3.20, p=0.32). Conversion to LRYGB increased the risk for readmission (6.16% vs. 3.77%; RR, 1.63; 95%CI, 1.37 to 1.94, p<0.01); reoperation (2.15% vs. 1.36%; RR, 1.57; 95%CI, 1.17 to 2.12, p=<0.01); intervention (3.19% vs. 1.32%; RR, 2.41; 95%CI, 1.82 to 3.19, p<0.01); leak (1.76% vs. 1.02%; RR, 1.57; 95%CI, 1.72 to 2.42, p<0.01); bleeding (1.66% vs. 1.00%; RR, 1.66; 95%CI, 1.7 to 2.34, p<0.01); and morbidity (4.97% vs. 2.35%; RR, 2.12; 95%CI, 1.70 to 2.63, p<0.01).

Conclusions

The study confirms that a single stage conversion of failed gastric banding is associated with greater morbidity and higher complication rates when converted to LRYGB versus LSG in the first 30 days postoperatively. These differences are significant with regards to readmission, reoperation, intervention, leak and bleed rates, and morbidity.

Progranulin and chemerin plasma level in obese patients with type 2 diabetes treated with a long-acting insulin analogue and premixed insulin analogue

Diabetes, referred to as the first non-infectious epidemic, covers a heterogenous group of metabolic diseases marked by hyperglycemia resulting from a defect of insulin secretion and/or insulin resistance. Highly endocrine active adipocytes, particularly those located in white adipose tissue, constitute a source of cytokines, growth factors and complement component as well as adipocytokines including chemerin and progranulin could be the key molecules in the pathomechanism of hypertension, dyslipidemia, metabolic disorders or diabetes type 2. In this study, it was decided to verify the existence of possible relationships between the plasma concentration of progranulin and chemerin and the values of intermediate indices of insulin sensitivity and insulin resistance in patients, both before and after the 6-month insulin therapy by long-acting insulin analogue and premixed insulin analogue. The level of laboratory parameters in blood plasma collected from the control group and from obese individuals with type 2 diabetes mellitus was estimated with the test kits using enzyme-linked immunosorbent assay (ELISA): the test of Mediagnost E103 GmbH GmbH, Reutlingen, Germany for progranulin; the test of BioVendor R&D, Brno, Czech Republic for chemerin. The aim of this study was to assess the progranulin and chemerin plasma level in obese individuals with type 2 diabetes, before and after 6 months of pharmacological treatment with a long-acting analogue human insulin or premixed insulin. In the blood plasma of untreated diabetics - in contrary to progranulin plasma concentration in diabetic patients after management implementation - progranulin was found to occur in a significantly higher concentration in relation to the level of this protein in the blood plasma of control group individuals. Despite the fact that 6-month therapy, both with the insulin mixture and with the long-acting analogue in people with diabetes, does not significantly affect the plasma chemerin concentration, the high, negative correlation between the progranulin and chemerin levels in the blood of individuals of the control group, and a positive one between the levels of progranulin and chemerin in people with diabetes before and after treatment was found. The conducted studies indicated the modified, in the course of diabetes type 2, mutual quantitative relations between progranulin and chemerin - the biological mediators of systemic metabolism, reflecting their active participation in the pathogenetic changes underlying type 2 diabetes. The obtained study results indicate a modification of mutual relationships of the adipocytokines assessed in the paper - progranulin and chemerin, associated with the development of the systemic inflammatory response occurring in the course of obesity which, by inducing insulin resistance, may consequently lead to type 2 diabetes. Taking into consideration the fact that the plasma progranulin and chemerin concentrations in obese patients with type 2 diabetes subjected to pharmacotherapy have not been assessed so far, it is possible that the obtained study results may cast light on the potential influence of the applied treatment on the systemic changes of the both adipocytokines involved in the pathomechanism of the mentioned disorder and thus create the possibility of implementing new therapeutic strategies in the management of patients with diabetes, which is an increasingly common, fast-spreading metabolic disease considered as a non-infectious epidemic of the 21^st century.

Erratum: Azimuthal Anisotropy of K_{S}^{0} and Λ+Λ[over ¯] Production at Midrapidity from Au+Au Collisions at sqrt[s]_{NN}=130 GeV [Phys. Rev. Lett. 89, 132301 (2002)]

This corrects the article DOI: 10.1103/PhysRevLett.89.132301.

Erratum: Azimuthal Anisotropy at the Relativistic Heavy Ion Collider: The First and Fourth Harmonics [Phys. Rev. Lett. 92, 062301 (2004)]

This corrects the article DOI: 10.1103/PhysRevLett.92.062301.

The comparison of modified minimally invasive and open surgical approaches in the treatment of epithelial thymic tumours

OBJECTIVES

Exploring the efficacy of a modified combined minimally invasive approach in patients with thymoma regardless of myasthenia gravis involvement in contrast to open surgery as the mainstay of treatment.

BACKGROUND

Primary epithelial thymic tumours are rare malignancies of the anterior mediastinum, often present with myasthenia gravis, and with good prognosis when assuming complete surgical resection. We present a modified mini-invasive technique (MIT) that is unique in its extent.

METHODS

Fifty-two patients were included in this retrospective study. Two groups of patients who had undergone different types of surgery were compared using the Mann-Whitney test (ordinal variables) and Fisher's exact test (binary variables). Changes after completing the surgical learning curve were observed.

RESULTS

There was a statistical difference when comparing early Masaoka stages (I‒II) with later stages in favour of the mini-invasive method (p=0.013). The duration of surgery was longer in the mini‑invasive group with a median value of 260 vs 133 min (p=0.001). The analysis of operation times revealed that after overcoming the learning curve period, the duration of surgery decreased (2008‒2012: 297 min; 2013‒2018: 199 min; p=0.005). The systemic complication rate was lower in the mini‑invasive method (26.1 % vs 3.4 %; p=0.035).

CONCLUSION

Our results showed the modified maximal minimally invasive thymectomy to be an effective and safe method, and after overcoming the learning curve, even superior to open surgery in cases with lower tumour stages in terms of its extent (Tab. 3, Fig. 1, Ref. 49).

A WALK-IN TYPE CALIBRATION CHAMBER FACILITY FOR 222Rn MEASURING DEVICES AND INTER-COMPARISON EXERCISES

A walk-in type 222Rn calibration chamber of volume 22.7 m3, which has traceability to international standards, is established at the Centre for Advanced Research in Environmental Radioactivity, Mangalore University, India. It has a human-machine interface communication system, a programmable logic controller and sensor feedback circuit for controlling and data acquisition of relative humidity (RH) and temperature (T). An innovative method for the generation of desired 222Rn concentration (a few hundred Bq m-3 up to about 36 kBq m-3) using soil gas as a source was adopted. Leak rates of 222Rn from the chamber for the mixing fan ON and OFF conditions were determined to be 0.0011 and 0.00018 h-1 respectively. With the exhaust system fully turned on, the maximum clearance rate of the chamber was 0.58 ± 0.07 h-1. Excellent spatial uniformity in 222Rn concentration in the chamber was confirmed (with a mean value of relative standard deviation < 12%) through measurements at 23 locations using CR-39 film-based passive devices. Demonstration of calibration applications was performed using charcoal canister and PicoRad vials as the 222Rn adsorption devices. The study shows that gamma spectrometry is a convenient alternative approach to liquid scintillation analysis of PicoRad vials for 222Rn measurement.

CHARACTERISTICS OF INDOOR RADON AND THORON CONCENTRATIONS IN CAVE DWELLINGS IN GANSU PROVINCE, CHINA

Short-term measurements were made in four different types of Chinese cave dwellings, 'ground', 'open-cut', 'aboveground' and 'underground', located in Gansu Province, China, in order to evaluate the diurnal and seasonal variations in indoor radon (222Rn) and thoron (220Rn) concentrations. As a result, in most of the 'ground' and 'open-cut' cave dwellings in summer, the indoor 222Rn concentrations during the nighttime were higher than those during the daytime. In the winter, such fluctuation was not observed. The daily indoor 222Rn concentrations in summer were higher than those in winter, excluding the 'aboveground' cave dwelling, and these concentrations depended on dwelling type, exhalation from the building materials and ventilation. In contrast with 222Rn, there seemed to be only very slight clear variations in 220Rn.

THE SCREENING INDOOR RADON AND PRELIMINARY STUDY OF INDOOR THORON CONCENTRATION LEVELS IN KUWAIT

Indoor measurements of radon and thoron in Kuwait were conducted during the years 2015 and 2016. In this study, 65 dwellings were selected for the long-term radon-thoron survey using passive nuclear track monitors. The monitors (at least one) were used at various locations in the dwellings for 83-306 days. Some measurements were also repeated at the same locations in different seasons. This current study is a preliminary thoron survey with relatively small sample size. The results showed that the range of thoron concentration was from below the lower limit of detection to 35 Bq m-3, whereas the range of radon concentration was within 10-202 Bq m-3. Furthermore, 22% of the radon results exceeded the WHO radon reference level of 100 Bq m-3. The analysis of variance showed a correlation between indoor radon concentration and the season. However, the thoron measurements were rather limited and the values were low. In addition, the relationship was investigated between radon and thoron concentrations involving the floor levels and the type of ventilation systems used.

Evaluation of Liver Graft Recipient Workup in Predicting of Early Cardiovascular Events During Liver Transplantation: A Single-Center Experience

BACKGROUND

Cardiovascular events (CVE) contribute to serious complications and death after liver transplantation (LT). Troponin I (TnI) level >0.07 mg/L and prior cardiac disease are known to be the independent predictors for posttransplant CVE. We evaluated single-center cardiac workup to predict early cardiovascular morbidity and mortality after LT.

PATIENTS AND METHODS

We recruited 105 consecutive liver transplant recipients (male/female, 59/46; mean age, 51.66 ± 11.67 years). The cardiological assessment at evaluation for LT included medical history, electrocardiogram, echocardiography, Holter monitoring, and exercise test. We collected data regarding CVE including hypotonia with catecholamine usage, arrhythmia, sudden cardiac death, pulmonary edema, and myocardial infarction within 7 days after LT.

RESULTS

CVE during LT occurred in 42 recipients (40%) and after LT in 9 patients (8.57%). Proposed cutoff level of TnI >0.07 mg/L did not correlate with CVE during operation (P = .73) or after LT (P = .47). CVE during LT was associated with arterial hypertension in medical history (P <.001), right ventricular systolic pressure (P< .05), and clinical scores: Child-Pugh (P = .04), Model for End-Stage Liver Disease (MELD) (P = .04), MELD incorporating serum sodium (P<.03), and integrated MELD score (P = .01). CVE after LT correlated only with arrhythmia (P<.001) and catecholamine usage (P < .05) perioperatively. Of interest, catecholamine usage during LT was associated with prolonged stay at the intensive care unit (P < .05).

CONCLUSION

The single-center algorithm with noninvasive cardiac procedures without TnI assessment is optimal in evaluation before LT; however, medical history and severity of the liver disease are crucial for short-term cardiovascular morbidity after LT.

Machine learning methods as a tool to analyse incomplete or irregularly sampled radon time series data

Machine learning is a class of statistical techniques which has proven to be a powerful tool for modelling the behaviour of complex systems, in which response quantities depend on assumed controls or predictors in a complicated way. In this paper, as our first purpose, we propose the application of machine learning to reconstruct incomplete or irregularly sampled data of time series indoor radon (²²²Rn). The physical assumption underlying the modelling is that Rn concentration in the air is controlled by environmental variables such as air temperature and pressure. The algorithms "learn" from complete sections of multivariate series, derive a dependence model and apply it to sections where the controls are available, but not the response (Rn), and in this way complete the Rn series. Three machine learning techniques are applied in this study, namely random forest, its extension called the gradient boosting machine and deep learning. For a comparison, we apply the classical multiple regression in a generalized linear model version. Performance of the models is evaluated through different metrics. The performance of the gradient boosting machine is found to be superior to that of the other techniques. By applying learning machines, we show, as our second purpose, that missing data or periods of Rn series data can be reconstructed and resampled on a regular grid reasonably, if data of appropriate physical controls are available. The techniques also identify to which degree the assumed controls contribute to imputing missing Rn values. Our third purpose, though no less important from the viewpoint of physics, is identifying to which degree physical, in this case environmental variables, are relevant as Rn predictors, or in other words, which predictors explain most of the temporal variability of Rn. We show that variables which contribute most to the Rn series reconstruction, are temperature, relative humidity and day of the year. The first two are physical predictors, while "day of the year" is a statistical proxy or surrogate for missing or unknown predictors.

AN INTERNATIONAL COOPERATION BY USING AN ALL-ENCOMPASSING PASSIVE RADON MONITOR

The recently developed radon film-badge makes it possible to measure radon indoors, in soil, in water and/or in aqueous media (e.g. mud). As a result of its wide response linearity, this monitor has been successfully used to measure radon in-water with concentrations from 10 to ~10 000 Bq/L. By exploiting the unique characteristics of this badge, a mini-survey has been carried out by Health Canada in which radon in water was measured from 12 private wells, as well as in tap water originating from the Ottawa River. Due to the widespread interest of different laboratories in using these passive monitors, laboratories were provided with plastic films to construct their own badges by using in-house CR-39 detectors. Monitors were then irradiated by a known radon concentration at the National Institute of Radiation Metrology (ENEA)'s radon chamber and sent back to each laboratory for processing and counting. Even though these laboratories have been using different etching- and counting-procedures, the film-badge responses varied only within ~12%.

The most recent international intercomparisons of radon and thoron monitors with the NIRS radon and thoron chambers

The fifth international intercomparison for radon and fourth for thoron monitors were conducted at National Institute of Radiological Sciences (Japan) with the radon and thoron chambers. The tests were made under two different exposures to radon and two exposures (in two rounds due to limited space in the thoron chamber) to thoron. In these most recent intercomparisons, two new graphical methods recommended by the ISO standard, Mandel's h statistic and the Youden plot, were implemented to evaluate the consistency between laboratories and within laboratories.The presented data indicated that the performance quality of laboratories for radon measurement as expressed by the percentage difference parameter has been stable since the first international intercomparison for passive monitors carried out in 2007, and it amounted to around 50 for 10 % of the difference from the reference value. The thoron exercise showed that further development and additional studies to improve its measuring methods and reliability are needed.

Invited article: radon and thoron intercomparison experiments for integrated monitors at NIRS, Japan

Inhalation of radon ((222)Rn) and its short-lived decay products and of products of the thoron ((220)Rn) series accounts for more than half of the effective dose from natural radiation sources. At this time, many countries have begun large-scale radon and thoron surveys and many different measurement methods and instruments are used in these studies. Consequently, it is necessary to improve and standardize technical methods of measurements and to verify quality assurance by intercomparisons between laboratories. Four international intercomparisons for passive integrating radon and thoron monitors were conducted at the NIRS (National Institute of Radiological Sciences, Japan). Radon exercises were carried out in the 24.4 m(3) inner volume walk-in radon chamber that has systems to control radon concentration, temperature, and humidity. Moreover, the NIRS thoron chamber with a 150 dm(3) inner volume was utilized to provide three thoron intercomparisons. At present, the NIRS is the only laboratory world-wide that has carried out periodic thoron intercomparison of passive monitors. Fifty laboratories from 26 countries participated in the radon intercomparison, using six types of detectors (charcoal, CR-39, LR 115, polycarbonate film, electret plate, and silicon photodiode). Eighteen laboratories from 12 countries participated in the thoron intercomparisons, using two etch-track types (CR-39 and polycarbonate) detectors. The tests were made under one to three different exposures to radon and thoron. The data presented in this paper indicated that the performance quality of laboratories for radon measurement has been gradually increasing. Results of thoron exercises showed that the quality for thoron measurements still needs further development and additional studies are needed to improve its measuring methods. The present paper provides a summary of all radon and thoron international intercomparisons done at NIRS from 2007 to date and it describes the present status on radon and thoron passive, one-time cycle monitors.

Thoron experimental room at the National Institute of Radiological Sciences (NIRS), Japan

A new thoron ((220)Rn) experimental room (TER) was established at National Institute of Radiological Sciences in 2011 to respond to the appearance of new passive devices for (220)Rn and its progeny ((212)Pb, (212)Bi) measurement. The room volume is 21.7 m(3) with a low air exchange rate, 0.016 h(-1). Environmental parameters, such as temperature, relative and absolute humidities, wind speed, aerosol distribution and concentration, are monitored, but not controlled. Commercially available lantern mantles (500 pcs), which can generate maximum concentrations of 6000 Bq m(-3) of (220)Rn and 2000 Bq m(-3) of its progeny, are used as a (220)Rn source. Based on preliminary results from the TER, stable and homogenised concentrations of (220)Rn and its progeny can be ensured; therefore, in the near future the room will be used for testing measuring instruments.

Levels of thoron and progeny in high background radiation area of southeastern coast of Odisha, India

Exposure to radon, (222)Rn, is assumed to be the most significant source of natural radiation to human beings in most cases. It is thought that radon and its progeny are major factors that cause cancer. The presence of thoron, (220)Rn, was often neglected because it was considered that the quantity of thoron in the environment is less than that of radon. However, recent studies have shown that a high thoron concentration was found in some regions and the exposure to (220)Rn and its progeny can equal or several time exceed that of (220)Rn and its progeny. The results of thoron and its progeny measurements in the houses of high background radiation area (HBRA) of the southeastern coast of Odisha, India presented here. This area is one of the high background radiation areas in India with a large deposit of monazite sand which is the probable source of thoron. Both active and passive methods were employed for the measurement of thoron and its progeny in cement, brick and mud houses in the study area. Thoron concentration was measured using RAD-7 and Raduet. A CR-39 track detector was employed for the measurement of environmental thoron progeny, both in active and passive modes. Thoron and its progeny concentrations were found to be comparatively high in the area. A comparison between the results obtained with various techniques is presented in this paper.

Effects of air exchange property of passive-type radon-thoron discriminative detectors on performance of radon and thoron measurements

Pairs of diffusion chambers with different air exchange rates are used in a large-scale survey to determine radon and thoron, separately. When they are enclosed in radon-proof bags for keeping after the exposure, since radon does not escape out immediately from the low-diffusion chamber, it leads to further exposure in the bags and disturbs the estimation of radon and thoron concentrations. In this study, the effects of the different air exchange properties of the radon-thoron discriminative detectors with CR-39 chips on the estimations of radon and thoron concentrations were investigated. The commercially available and frequently used detectors, Raduet, are examined in this study. The result shows that radon escapes out in 10 h. When degassing is not enough after the exposure in a calibration experiment or high-background radiation area, the residual radon causes the overestimation of the radon concentration and increase in the uncertainty in the thoron concentration, i.e. a low-performance quality of radon and thoron measurements.

Determination of the minimum measurement time for estimating long-term mean radon concentration

Radon measurements, as do any measurements, include errors in their readings. The relative values of such errors depend principally on the measurement methods used, the radon concentration to be measured and the duration of the measurements. Typical exposure times for radon surveys using passive detectors [nuclear track detectors, activated charcoal, electrostatic (E-perm), etc.)] may extend from a few days to months, whereas, in the case of screening methods utilising active radon monitors (AlphaGUARD, RAD7, EQF, etc.), the measurements may be completed quickly within a few hours to a few days. Thus, the latter may have relatively large error values, which affect the measurement accuracy significantly compared with the former measurements made over long time periods. The method presented in this paper examines the uncertainty of a short-term radon measurement as an estimate of the long-term mean and suggests a minimum measurement time to achieve a given margin of uncertainty of that estimate.

The combined algorithm of venous ulcer therapy

AIM

This prospective study was undertaken to find a new combined algorithm to help patients suffering from long-term chronic non-healing venous ulcers.

METHODS

A total number of 20 patients suffering from chronic venous ulcers and important co-morbidities such as diabetes mellitus or cardiac failure and not responding to other therapeutic modalities were treated at our surgical department with a combination of compressive sclerotherapy, and maggot debridement therapy (MDT) using larvae of green blowfly Lucilia sericata.

RESULTS

Using the combined therapy we have achieved a significant clinical effect in 19 patients (95 %). In 1 patient, this effect was only impermanent while 5 patients (25 %) were completely cured. Eleven patients (55 %) benefited despite incomplete healing of the ulcer. With three of our patients we have lost contact.

CONCLUSIONS

Even though the number of patients in our study is not large, we have achieved remarkable results with the combined algorithm of venous ulcer therapy. We start the healing process with compressive sclerotherapy and when this kind of therapy does not bring about the expected effect, we continue with Maggot debridement therapy. This combination of therapeutic modalities appears to be very effective and efficient (Fig. 2, Ref. 16).

Long-term measurements of thoron, its airborne progeny and radon in 205 dwellings in Ireland

Long-term (circa 3 months) simultaneous measurements of indoor concentrations of thoron gas, airborne thoron progeny and radon were made using passive alpha track detectors in 205 dwellings in Ireland during the period 2007-09. Thoron progeny concentrations were measured using passive deposition monitors designed at the National Institute of Radiological Sciences (NIRS), Japan, whereas thoron gas concentrations were measured using Raduet detectors (Radosys, Budapest). Radon concentrations were measured in these dwellings by means of NRPB/SSI type alpha track radon detectors as normally used by the Radiological Protection Institute of Ireland (RPII). The concentration of thoron gas ranged from <1 to 174 Bq m(-3) with an arithmetic mean (AM) of 22 Bq m(-3). The concentration of radon gas ranged from 4 to 767 Bq m(-3) with an AM of 75 Bq m(-3). For radon, the estimated annual doses were 0.1 (min), 19.2 (max) and 1.9 (AM) mSv y(-1). The concentration of thoron progeny ranged from <0.1 to 3.8 Bq m(-3) [equilibrium equivalent thoron concentration (EETC)] with an AM of 0.47 Bq m(-3) (EETC). The corresponding estimated annual doses were 2.9 (max) and 0.35 (mean) mSv y(-1). In 14 or 7% of the dwellings, the estimated doses from thoron progeny exceeded those from radon.

A comparative study of thorium activity in NORM and high background radiation area

Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.

Quality assurance and quality control for thoron measurement at NIRS

The National Institute of Radiological Sciences (NIRS) has developed passive radon ((222)Rn)-thoron ((220)Rn) discriminative detectors for a large-scale survey and has established a thoron chamber to calibrate such detectors. In order to establish quality assurance and quality control for the (220)Rn measurement at NIRS, intercomparison studies have been carried out. The intercomparisons using a scintillation cell method, which has been used as a standard for (220)Rn measurement at NIRS, were conducted at New York University (NYU, USA) and Physikalisch-Technische Bundesanstalt (PTB, Germany). As a result, it was found that the result from the NIRS was in good agreement with that from the NYU. On the other hand, it was observed that the relative discrepancy between the (220)Rn concentrations from the NIRS and PTB monitors was, on average, >50 %. Using the NIRS (220)Rn chamber, the international intercomparison experiment for passive (220)Rn detectors started in 2008.

Influence of soil environmental parameters on thoron exhalation rate

Field measurements of thoron exhalation rates have been carried out using a ZnS(Ag) scintillation detector with an accumulation chamber. The influence of soil surface temperature and moisture saturation on the thoron exhalation rate was observed. When the variation of moisture saturation was small, the soil surface temperature appeared to induce a strong effect on the thoron exhalation rate. On the other hand, when the variation of moisture saturation was large, the influence of moisture saturation appeared to be larger than the soil surface temperature. The number of data ranged over 405, and the median was estimated to be 0.79 Bq m(-2) s(-1). Dependence of geology on the thoron exhalation rate from the soil surface was obviously found, and a nationwide distribution map of the thoron exhalation rate from the soil surface was drawn by using these data. It was generally high in the southwest region than in the northeast region.

International intercomparisons of integrating radon/thoron detectors with the NIRS radon/thoron chambers

Intercomparisons of radon/thoron detectors play an important role not only for domestic radon/thoron survey but also for international or interregional discussion about radon/thoron mapping in dwellings as well as that in the soil. For these purposes, it is necessary to improve and standardise technical methods of measurement and to verify quality assurance by intercomparisons between laboratories. Therefore, the first thoron international intercomparison was provided at the NIRS (National Institute of Radiological Sciences, Japan) thoron chamber with a 150 dm(3) inner volume. In addition, a second intercomparison of radon detectors was conducted at NIRS with a 24.4 m(3) inner volume walk-in radon chamber. Only etched-track detectors were used during thoron intercomparison as well as three types for the radon intercomparison: etched-track, charcoal and electret. In general, 45 % results for thoron experiment do not differ more than 20 % from the reference value of thoron concentration and 69 % for radon.

Preliminary indoor thoron measurements in high radiation background area of southeastern coastal Orissa, India

This paper presents the preliminary results of radon and thoron measurements in the houses of Chhatrapur area of southeastern coast of Orissa, India. This area is one of the high radiation background radiation areas in India, which consists of monazite sand as the source of thoron. Both active and passive methods were employed for the measurements. Radon and thoron concentrations were measured in the houses of Chhatrapur area using twin cup radon dosemeters, RAD7 and radon-thoron discriminative detector (Raduet). Thoron progeny concentration was also measured in the houses using deposition rate measurements. Radon and thoron concentrations in the houses of study area were found to vary from 8 to 47 Bq m(-3) and the below detection level to 77 Bq m(-3), respectively. While thoron progeny concentration in these houses ranges between 0.17 and 4.24 Bq m(-3), preliminary investigation shows that the thoron concentration is higher than radon concentration in the houses of the study area. The thoron progeny concentration was found to be comparatively higher, which forms a base for further study in the area. The comparison between the results of various techniques is presented in this paper.

Separately measuring radon and thoron concentrations exhaled from soil using AlphaGUARD and liquid scintillation counter methods

It was shown that radon and thoron concentrations exhaled from soil were separately measured using the AlphaGUARD and liquid scintillation counter (LSC) methods. The thoron concentrations from the RAD 7 were used to create the conversion equation to calculate thoron levels with the AlphaGUARD. However, the conversion factor was found to depend on the air flow rate. When air containing thoron of ∼60 kBq m(-3) was fed to the scintillation cocktail, thoron and thoron progeny could not be measured with the LSC method. The radon concentration of about 10 kBq m(-3) was measured with three methods, first with the LSC method and then with two AlphaGUARDs (one in the diffusion mode and the other in the flow mode (0.5 l min(-1))). There were no significant differences between these results. Finally, it was shown that the radon and thoron concentrations in air could be measured with the AlphaGUARD and LSC methods.

Long-term determination of airborne radon progeny concentrations using LR 115 detectors and the effects of thoron

The 'proxy equilibrium factor' (F(p)) method has been developed for long-term determination of airborne radon progeny concentrations using LR 115 solid-state nuclear track detectors. In this paper, the effects of (220)Rn on the F(p) method have been studied. The correction to the track density was related to a parameter α which was the ratio of the sum of activity concentrations of alpha-particle emitting radionuclides in the (220)Rn decay chain to the activity concentration of (220)Rn alone. Under commonly encountered circumstances, α could not be smaller than 2. An attempt was made to verify this using the exposure chamber at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A most interesting observation of α < 2 for very high (220)Rn concentrations and very low equilibrium factors for (220)Rn in the exposure chambers was made. A possible explanation was the substantial deposition of (216)Po under the extreme conditions inside the exposure chambers.

High natural radiation exposure in radon spa areas: a detailed field investigation in Niska Banja (Balkan region)

The measurement campaigns have been done in the rural community of Niska Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron concentrations were found to be more than 1kBqm(-3) and 200Bqm(-3), respectively. Extremely high concentrations of soil-gas radon (>2000kBqm(-3)) and radon exhalation rates (1.5mBqm(-2)s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation.

Distributions of charged hadrons associated with high transverse momentum particles in pp and Au+Au collisions at sqrt[sNN]=200 GeV

Charged hadrons in [EQUATION: SEE TEXT] associated with particles of [EQUATION: SEE TEXT] are reconstructed in pp and Au+Au collisions at sqrt[sNN]=200 GeV. The associated multiplicity and p magnitude sum are found to increase from pp to central Au+Au collisions. The associated p distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed.

Open charm yields in d+Au collisions at squareroot[sNN]=200 GeV

Midrapidity open charm spectra from direct reconstruction of D0(D0)-->K-/+pi+/- in d+Au collisions and indirect electron-positron measurements via charm semileptonic decays in p+p and d+Au collisions at squareroot[sNN]=200 GeV are reported. The D0(D0) spectrum covers a transverse momentum (pT) range of 0.1<pT<3 GeV/c, whereas the electron spectra cover a range of 1<pT<4 GeV/c. The electron spectra show approximate binary collision scaling between p+p and d+Au collisions. From these two independent analyses, the differential cross section per nucleon-nucleon binary interaction at midrapidity for open charm production from d+Au collisions at BNL RHIC is dsigma(NN)cc/dy=0.30+/-0.04(stat)+/-0.09(syst) mb. The results are compared to theoretical calculations. Implications for charmonium results in A+A collisions are discussed.

Radon concentration in soil gas around local disjunctive tectonic zones in the Krakow area

The purpose of this study was to investigate radon in the vicinity of geologic fault zones within the Krakow region of Poland, and to determine the influence of such formations on enhanced radon concentrations in soil. Radon ((222)Rn and (220)Rn) concentration measurements in soil gas (using ionization chamber AlphaGUARD PQ2000 PRO and diffusion chambers with CR-39 detectors), as well as radioactive natural isotopes of radium, thorium and potassium in soil samples (using gamma ray spectrometry with NaI(Tl) and HPGe detectors), were performed. Site selection was based on a geological map of Krakow. Geophysical methods (ground penetrating radar and shallow acoustic seismic) were applied to recognize the geological structure of the area and to locate the predicted courses of faults. Elevated levels of radon and thoron in soil gas were found in the study area when compared with those observed in an earlier survey covering Krakow agglomeration. For (222)Rn, the arithmetic mean of registered concentration values was 39 kBq/m(3) (median: 35.5 kBq/m(3)). For (220)Rn, the arithmetic mean was 10.8 kBq/m(3) and median 11.8 kBq/m(3).

Azimuthal anisotropy and correlations at large transverse momenta in p + p and Au + Au collisions at square root sNN=200 GeV

Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au + Au collisions at square root s(NN)=200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au + Au collisions to those in p + p at the same energy. The elliptic anisotropy v(2) is found to reach its maximum at p(t) approximately 3 GeV/c, then decrease slowly and remain significant up to p(t) approximately 7-10 GeV/c. Stronger suppression is found in the back-to-back high-p(t) particle correlations for particles emitted out of plane compared to those emitted in plane. The centrality dependence of v(2) at intermediate p(t) is compared to simple models based on jet quenching.

Quantitative assessment of regional myocardial function in a rat model of myocardial infarction using tagged MRI

We characterized global and regional left ventricular (LV) function during post myocardium infarction (MI) remodeling in rats, which has been incompletely described by previous MRI studies. To assess regional wall motion, four groups of infarcted animals corresponding to 1-2, 3-4, 6-8 and 9-12 weeks post-MI respectively were imaged using a fast gradient echo sequence with a 2D spatial modulation of magnetization (SPAMM) tagging preparation. An additional group was serially imaged (1-2 and 6-7 weeks post-MI) to assess the global function. Regional and global functional parameters of infarcted rats were compared to non-infarcted normal rats. Compared to normal rats, a decrease in ejection fraction (70 +/-7 vs. 40 +/- 8%, p<0.05) was observed in rats with MI. Maximal and minimal principal stretches (lambda1, lambda2) and strains (E1, E2), principal angle (beta) and displacement varied regionally in normal rats but deviated significantly from the normal values in rats with MI particularly in the infarcted and adjacent zones. Not only was strain magnitude reduced segmentally post-MI, but strain direction became more circumferentially oriented, particularly in rats with larger infarctions. We report the first regional myocardial strain values in normal and infarcted rats. These results parallel findings in humans, and provide a unique tool to examine regional mechanical influences on the remodeling process.

Multistrange baryon production in Au-Au collisions at sqrt[s(NN)]=130 GeV

The transverse mass spectra and midrapidity yields for Xis and Omegas are presented. For the 10% most central collisions, the (-)Xi(+)/h(-) ratio increases from the Super Proton Synchrotron to the Relativistic Heavy Ion Collider energies while the Xi(-)/h(-) stays approximately constant. A hydrodynamically inspired model fit to the Xi spectra, which assumes a thermalized source, seems to indicate that these multistrange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to pi, K, p, and Lambdas.

Cross sections and transverse single-spin asymmetries in forward neutral-pion production from proton collisions at sqrt[s]=200 GeV

Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at sqrt[s]< or =20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p(T)>1 GeV/c at a polarized proton collider.

Identified particle distributions in pp and Au+Au collisions at square root of (sNN)=200 GeV

Transverse mass and rapidity distributions for charged pions, charged kaons, protons, and antiprotons are reported for square root of [sNN]=200 GeV pp and Au+Au collisions at Relativistic Heary Ion Collider (RHIC). Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.

Rho0 production and possible modification in Au+Au and p+p collisions at square root [sNN] = 200 GeV

We report results on rho(770)(0)-->pi(+)pi(-) production at midrapidity in p+p and peripheral Au+Au collisions at sqrt[s(NN)]=200 GeV. This is the first direct measurement of rho(770)(0)-->pi(+)pi(-) in heavy-ion collisions. The measured rho(0) peak in the invariant mass distribution is shifted by approximately 40 MeV/c(2) in minimum bias p+p interactions and approximately 70 MeV/c(2) in peripheral Au+Au collisions. The rho(0) mass shift is dependent on transverse momentum and multiplicity. The modification of the rho(0) meson mass, width, and shape due to phase space and dynamical effects are discussed.

Azimuthal anisotropy at the relativistic heavy ion collider: the first and fourth harmonics

We report the first observations of the first harmonic (directed flow, v(1)) and the fourth harmonic (v(4)), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v(2)) generated at RHIC. From the correlation of v(2) with v(1) it is determined that v(2) is positive, or in-plane. The integrated v(4) is about a factor of 10 smaller than v(2). For the sixth (v(6)) and eighth (v(8)) harmonics upper limits on the magnitudes are reported.

Particle-type dependence of azimuthal anisotropy and nuclear modification of particle production in Au+Au collisions at square root of sNN=200 GeV

We present STAR measurements of the azimuthal anisotropy parameter v(2) and the binary-collision scaled centrality ratio R(CP) for kaons and lambdas (Lambda+Lambda) at midrapidity in Au+Au collisions at square root of s(NN)=200 GeV. In combination, the v(2) and R(CP) particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish p(T) approximately 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The K(0)(S) and Lambda+Lambda v(2) values are consistent with expectations of constituent-quark-number scaling from models of hadron formation by parton coalescence or recombination.

Central airways stenoses management--a single institution experience

Tracheal stenosis is a serious, life-threatening disease with an increasing tendency. The number of complicated tracheal lesions, where resection and anastomosis can not be performed, still increases and the situation requires solution by endoprosthesis. Consequent the management of such complicated obstructive tracheal lesions is individual and time-consuming. The main objective of this study is to review the single institution experience with central airways stenosis treatment and to define the role of endotracheal stenting in tracheal reconstruction surgery. This study presents the retrospective analysis of tracheal stenosis reconstruction by means of our own modification of Montgomery T-tube. (Tab. 3, Fig. 3, Ref. 12.)

Pion-Kaon correlations in central Au+Au collisions at square root [sNN] = 130 GeV

Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[s(NN)]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.

Three-pion Hanbury Brown-Twiss correlations in relativistic heavy-ion collisions from the STAR experiment

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at sqrt[s(NN)]=130 GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.