MODELING AND EXPERIMENTS TO ESTIMATE RADON EMANATION FACTOR IN SOIL-GRAIN SIZE AND MOISTURE EFFECT.

The influence of soil grain size on its radon emanation mechanism was investigated by developing a Monte-Carlo model. The proposed model supplements the previous formulations by accounting for the effect elicited by specific surface area of the sample. The specific surface area of a sample is governed by its grain size and it strongly influences the emanation rate which is a surface phenomenon. The emanation study was further extended to include the moisture effect. Experiments were carried out with two soil samples; Soil-2 and Soil-4 collected from different terrains, to analyze the role played by moisture in the emanation mechanism. The above model was augmented with provisions to include the moisture input. The model could reproduce the experimental results. There is an abrupt increase in the emanation factor when the moisture content changes from 0 to 2%. Thereafter, the increase is gradual and finally becomes steady when the moisture level reaches 10%. Soil-2 and Soil-4 showed sizeable difference in their radon emanation factor values. This could be explained based on the parent226Ra distribution pattern which stems from the mineralogical composition of the samples. Quartz was predominantly found in Soil-2, whereas Soil-4 shows peaks corresponding to minerals namely ilmenite, Rutile and Zircon confirming relatively higher concentration of heavy minerals than Soil-2. The emanation factor values of the individual minerals reported in the literature were used to decide upon the 226Ra distribution depth and with this input the model to ascertain the experimental observations.

QUANTIFICATION OF BACK DIFFUSION IN RADON AND THORON EXHALATION RATE MEASUREMENTS.

The radon (222Rn) and thoron (220Rn) fluxes from the soil and building materials are the major contributors to their indoor levels. Hence, the measurement of radon and thoron exhalation rates from the source matrix becomes the foremost step in controlling the indoor radon and thoron exposure. It is a challenge to measure the exhalation rates without disturbing the natural conditions. The back-diffusion phenomenon modifies the exhalation rate. The work presented here is to measure the back-diffusion coefficient and takes it into consideration while estimating the exhalation rate. For radon measurements, the back-diffusion coefficient and the free exhalation rates were simultaneously estimated by adopting a novel methodology. The leak rate of the experimental setup measured by this methodology was agreeable with the value measured by adopting the standard technique. In the case of thoron, the back-diffusion effect was found to be negligible for the present experimental conditions and it is duly explained. The above results were obtained by analyzing two soil samples with high 238U and 232Th content collected from monazite-rich coastal area.

Study of Radon and Thoron exhalation from soil samples of different grain sizes.

The exhalation of radon (222Rn) and thoron (220Rn) from a porous matrix depends on the emanation of them from the grains by the recoil effect. The emanation factor is a quantitative estimate of the emanation phenomenon. The present study is to investigate the effect of grain size of the soil matrix on the emanation factor. Soil samples from three different locations were fractionated into different grain size categories ranging from <0.1 to 2mm. The emanation factors of each of the grain size range were estimated by measuring the mass exhalation rates of radon and thoron and the activity concentrations of 226Ra and 232Th. The emanation factor was found to increase with decrease in grain size. This effect was made evident by keeping the parent radium concentration constant for all grain size fractions. The governing factor is the specific surface area of the soil samples which increases with decrease in grain size.

Soil radioactivity measurements and estimation of radon/thoron exhalation rate in soil samples from Kalpakkam residential complex.

The objective of this study is to compute the primordial radionuclides activity in soil samples and estimate the radon/thoron exhalation rates. A total of 25 locations were chosen for the study at Kalpakkam. Ambient radiation levels were monitored prior to collection of samples, which were subjected to gamma spectrometry. While (238)U concentration was found to be below detectable limit, the activities of (232)Th and (40)K were varying from 34.53 to 1093.11 Bq kg(-1) and 36.6 to 570.08 Bq kg(-1), respectively. The radium equivalent activities (Raeq) were in the range of 83-1574 Bq kg(-1). There was no appreciable radon exhalation, and the thoron surface exhalation rate varied from 942 to 7720 Bq m(-2) h(-1). The annual effective dose was ranging from 0.05 to 0.81 mSv y(-1). Good correlation was observed between (232)Th content and thoron exhalation rate. The details of the study are presented in this article.

Impact of implementation of NRHM program on NMR in Tamil Nadu (TN): a case study.

The Government of India had set up the National Rural Health Mission (NRHM) in 2005 in an effort towards providing quality healthcare to the underserved rural areas and also to achieve the Millennium Development Goals (MDGs) by 2015. While the trends in child and maternal mortality show great progress by India since 1990 with steady decline in Maternal Mortality Ratio (MMR) and Infant Mortality Rate (IMR), a comparison of the predicted trend and target of MDGs show that India would fall short by a few points. In contrast, Tamil Nadu has reached its MDGs and is ensuring sustained progress in reducing child and maternal mortality with an effective implementation of the various schemes of NRHM. Tamil Nadu leads the way in ensuring universal health coverage leveraging the expertise and funds of NRHM by providing round the clock services, introducing new and innovative programs to improve outcomes and regular monitoring of the functional operation and outcomes to ensure effective implementation. Adopting the features of the Tamil Nadu model of healthcare system that caters to their particular state and effectively implementing the initiatives of NRHM would help the other states in considerably reducing the child and maternal mortality and also ensure early achievement of MDGs by the nation.

High ratios of plasma and platelets to packed red blood cells do not affect mortality in nonmassively transfused patients.

BACKGROUND: Administration of high transfusion ratios in patients not requiring massive transfusion might be harmful. We aimed to determine the effect of high ratios of fresh frozen plasma (FFP) and platelets (PLT) to packed red blood cells (PRBC) in nonmassively transfused patients. METHODS: Records of 1,788 transfused trauma patients who received <10 units of PRBC in 24 hours at 23 United States Level I trauma centers were reviewed. The relationship between ratio category (low and high) and in-hospital mortality was assessed with propensity-adjusted multivariate proportional hazards models. RESULTS: At baseline, patients transfused with a high FFP:PRBC ratio were younger, had a lower Glasgow Coma Scale score, and a higher Injury Severity Score. Those receiving a high PLT:PRBC ratio were older. The risk of in-hospital mortality did not vary significantly with FFP:PRBC ratio category. Intensive care unit (ICU)-free days, hospital-free days, and ventilator-free days did not vary significantly with FFP:PRBC ratio category. ICU-free days and ventilator-free days were significantly decreased among patients in the high (≥1:1) PLT:PRBC category, and hospital-free days did not vary significantly with PLT:PRBC ratio category. The analysis was repeated using 1:2 as the cutoff for high and low ratios. Using this cutoff, there was still no difference in mortality with either FFP:PRBC ratios or platelet:PRBC ratios. However, patients receiving a >1:2 ratio of FFP:PRBCs or a >1:2 ratio PLT:PRBCs had significantly decreased ICU-free days and ventilator-free days. CONCLUSIONS: FFP:PRBC and PLT:PRBC ratios were not associated with in-hospital mortality. Depending on the threshold analyzed, a high ratio of FFP:PRBC and PLT:PRBC transfusion was associated with fewer ICU-free days and fewer ventilator-free days, suggesting that the damage control infusion of FFP and PLT may cause increased morbidity in nonmassively transfused patients and should be rapidly terminated when it becomes clear that a massive transfusion will not be required.

A predictive model for mortality in massively transfused trauma patients.

BACKGROUND: Improvements in trauma systems and resuscitation have increased survival in severely injured patients. Massive transfusion has been increasingly used in the civilian setting. Objective predictors of mortality have not been well described. This study examined data available in the early postinjury period to identify variables that are predictive of 24-hour- and 30-day mortality in massively transfused trauma patients. METHODS: Massively transfused trauma patients from 23 Level I centers were studied. Variables available on patient arrival that were predictive of mortality at 24 hours were entered into a logistic regression model. A second model was created adding data available 6 hours after injury. A third model evaluated mortality at 30 days. Receiver operating characteristic curves and the Hosmer-Lemeshow test were used to assess model quality. RESULTS: Seven hundred four massively transfused patients were analyzed. The model best able to predict 24-hour mortality included pH, Glasgow Coma Scale score, and heart rate, with an area under the receiver operating characteristic curve (AUROC) of 0.747. Addition of the 6-hour red blood cell requirement increased the AUROC to 0.769. The model best able to predict 30-day mortality included the above variables plus age and Injury Severity Score with an AUROC of 0.828. CONCLUSION: Glasgow Coma Scale score, pH, heart rate, age, Injury Severity Score, and 6-hour red blood cell transfusion requirement independently predict mortality in massively transfused trauma patients. Models incorporating these data have only a modest ability to predict mortality and should not be used to justify withholding massive transfusion in individual cases.

Detection of E. coli O157:H7 in raw ground beef by Pathatrix™ immunomagnetic-separation, real-time PCR and cultural methods.

Detection of Escherichia coli O157:H7 by conventional cultural methods can be difficult in food matrices with a high background flora such as raw ground beef. Raw ground beef samples, artificially contaminated separately with five strains of E. coli O157:H7 at low (~0.2 cfu/g) and high (~2 cfu/g) levels, were enriched by two enrichment protocols; buffered peptone water (BPW) at 37 °C for 5h and 24h and modified buffered peptone water with pyruvate (mBPWp) for 5h at 37 °C followed by adding selective agents and incubating at 42 °C to 24h. Detection of added E. coli O157:H7 by real-time PCR (RTiPCR) and recovery on isolation agars was performed before and after PATHATRIX™ immunomagnetic separation (IMS). RTiPCR detection and cultural recovery of inoculated E. coli O157:H7 after 5h enrichment were poor at 0.21-0.24 cfu/g. The addition of IMS after 5h enrichment did not improve RTiPCR detection but markedly improved recovery by culturing. By extending enrichment to 24h, RTiPCR detection improved to 76% for either enrichment protocol without IMS. When 24h enrichment was followed by IMS, RTiPCR detection was also further improved. Cultural recovery after 24h enrichment was 56% and 84% without IMS and 100% and 92% after IMS for BPW and mBPWp respectively. Extended enrichment to 24h followed by IMS was found to be sensitive and reliable for detection and cultural recovery from raw ground beef using either enrichment method.

Management and outcomes of traumatic colon injury in civilian and military patients.

Divergent injury patterns may indicate the need for differing strategies in combat and civilian trauma patients. This study aims to compare outcomes of colon injury management in these two populations. Parallel retrospective reviews were conducted comparing warfighters (n = 59) injured downrange and subsequently transferred to the United States with civilians (n = 30) treated at a United States Level I trauma center. Patient characteristics, mechanisms of injury, treatment course, and complications were compared. The civilian (CP) and military (MP) populations did not differ in Injury Severity Score (MP 20 vs CP 26; P = 0.41). The MP experienced primarily blast injuries (51%) as opposed to blunt trauma (70%; P < 0.01) in the CP. The site of colon injury did not differ between groups (P = 0.15). Initial management was via primary repair (53%) and resection and anastomosis (27%) in the CP versus colostomy creation (47%) and stapled ends (32%) in the MP (P < 0.001). Ultimately, the CP and MP experienced equivalent continuity rates (90%). Overall complications (MP 68% vs CP 53%; P = 0.18) and mortality (MP 3% vs CP 3%; P = 0.99) did not differ between the two groups. The CP and MP experience different mechanisms and initial management of colon injury. Ultimately, continuity is restored in the majority of both populations.

Comparison of abdominal damage control surgery in combat versus civilian trauma.

BACKGROUND: The majority of individuals who perform damage control surgery in the military arena are trained in civilian venues. Therefore, it is important to compare and contrast damage control performed in civilian and military settings. In contrast to civilian trauma, which is primarily caused by blunt injury and addressed at one or two surgical facilities, combat casualties primarily sustain explosion-related injuries and undergo treatment at multiple levels of care across continents. We aimed to compare patients undergoing abdominal damage control surgery across these two very different settings. METHODS: Parallel retrospective reviews were conducted over 2 years (2005-2006) in a combat setting and at a US Level I trauma center. Patients were examined during the first 7 days after injury. RESULTS: The civilian population (CP) was older (40 vs. 23; p < 0.01) with a higher injury severity score (35 vs. 27; p < 0.02). The CP experienced greater blunt injury than the military population (MP) (83 vs. 4%; p < 0.01). Explosion-related injury was only present in the MP (64%). At baseline, the CP presented with lower systolic blood pressure (108 vs. 126) and larger base deficit (9.8 vs. 6.5; p < 0.05). The MP underwent more surgeries (3.5 vs. 2.9; p = 0.02) with similar rates of fascial closure (48.7% vs. 70.0%; p = 0.11). Complication rates were similar between the CP and the MP (43% vs. 58%, respectively; p = 0.14). CONCLUSIONS: Military and civilian trauma patients who undergo damage control surgery experience similar fascial closure rates despite differing demographics and widely disparate mechanisms of injury. The MP undergoes a greater number of procedures than the CP, but complication rates do not differ between the groups.

High transfusion ratios are not associated with increased complication rates in patients with severe extremity injuries.

BACKGROUND: High transfusion ratios of plasma to packed red blood cells (>1:2) have been associated with increased survival and increased complications in patients receiving massive transfusion (MT). We hypothesized that high ratio transfusion would be associated with no survival benefit and increased complications in combat victims with compressible hemorrhage. METHODS: A retrospective analysis of soldiers injured in the current conflict during 5 years (n = 2,105) who received blood was performed on those with isolated extremity (abbreviated injury scale extremity score > or = 3 and abbreviated injury scale score 0-2 in all other regions) injury comparing those who received a MT with those who did not. Transfusion ratios in the first 24 hours were correlated with outcomes. RESULTS: Injury severity score (14.6 vs. 12.1; p < 0.05), international normalized ratio (1.65 vs. 1.28; p < 0.05), and base deficit (8.0 vs. 3.7; p < 0.05) were higher in the MT group. High transfusion ratios were associated with a trend toward decreased mortality (17.2% vs. 6.9%; p = 0.07) in MT patients and no increased complications (20.7% vs. 26.4%; p > 0.05). In those receiving a non-MT, high ratios were associated with similar mortality (4.8% vs. 3.9%; p > 0.05) and complications (12.4% vs. 9.2%; p > 0.05). CONCLUSIONS: Extremity injured patients receiving MT may benefit from high transfusion ratios and do not experience increased complications. No change in mortality or complications was observed in non-MT patients across transfusions ratios. High transfusion ratios are not associated with increased complications in patients with isolated extremity injury regardless of whether a MT is required.

Oncologic outcomes after resection of rectal cancer: Laparoscopic versus open approach.

BACKGROUND: This study examined outcomes of laparoscopic and open rectal cancer surgery in a community hospital setting. METHODS: A community health care system cancer registry was reviewed retrospectively (2004-2007) for rectal cancer patients undergoing surgical treatment. Primary end points were rates of recurrence and survival. RESULTS: Both open and laparoscopic resection groups had similar demographic, treatment, and tumor characteristics. Most patients in the open resection and laparoscopic resection populations experienced no recurrence (79% vs 83%, respectively; P = .5). Overall, the groups had similar mean (88% vs 96%, respectively; P = .4) and disease-free (21 and 23 months, respectively; P = .5) survival. CONCLUSIONS: In a community hospital setting, laparoscopic resection of rectal cancer was found to be as safe and effective as open resection in selected patients.

Splenectomy leads to a persistent hypercoagulable state after trauma.

BACKGROUND: It was hypothesized that splenectomy following trauma results in hypercoagulability. METHODS: A prospective, nonrandomized, single-center study was performed to evaluate coagulation parameters in trauma patients with splenic injury. RESULTS: Patients with splenectomy (n = 30) and nonoperative management (n = 50) were enrolled. Splenectomy patients were older, had higher Injury Severity Scores, and had longer intensive care unit and hospital stays (P < .05). Splenectomy patients had significantly increased white blood cell counts and platelet counts at baseline and follow-up (P < .01). Fibrinogen was initially elevated in both groups and remained elevated in the splenectomy group (P < .05). Tissue plasminogen activator, plasminogen activator inhibitor-1, and activated partial thromboplastin time were higher in splenectomy patients only at baseline (P < .05). Baseline thromboelastography showed faster fibrin cross-linking and enhanced fibrinolysis following splenectomy (P < .05). Only clot strength was greater at follow-up in the splenectomy group (P < .01). Deep venous thrombosis developed in 7% of splenectomy patients and no control patients (P = .03). CONCLUSIONS: A significant difference in deep venous thrombosis formation was noted, and coagulation assays indicated persistent hypercoagulability following splenectomy for trauma.

Emerging therapies in traumatic hemorrhage control.

PURPOSE OF REVIEW: Care of the injured patient is a dynamic process. Hemorrhage remains the primary cause of preventable death after trauma. Rapid and effective early care can improve survival and outcomes. Emerging therapies to address traumatic hemorrhage will be discussed. RECENT FINDINGS: Current concepts in trauma care include damage control resuscitation with rapid surgical correction of bleeding; prevention of the development of the lethal triad; limitation of crystalloid administration and application of high ratios of plasma and platelets to packed red blood cells. Prehospital resuscitation strategies can effect care of the hemorrhaging trauma patient, as well. The goal should be to preserve vital functions without increasing the risk for further bleeding. The concept of hypotensive resuscitation has been formulated to address this issue. The type of resuscitation fluid also plays an important role, with novel fluids currently being studied for routine use. Compressible hemorrhage constitutes an important component of potentially survivable injury. Hemostatic dressings and tourniquets can prove essential to the management of combat and civilian wounds. SUMMARY: Given the potential to preserve life with appropriate attention applied to the bleeding trauma victim, it is vitally important to explore the options currently available and continue to make improvements in care.

A high ratio of plasma and platelets to packed red blood cells in the first 6 hours of massive transfusion improves outcomes in a large multicenter study.

BACKGROUND: In trauma, most hemorrhagic deaths occur within the first 6 hours. This study examined the effect on survival of high ratios of fresh frozen plasma (FFP) and platelets (PLTs) to packed red blood cells (PRBCs) in the first 6 hours. METHODS: Records of 466 massive transfusion trauma patients (>or=10 U of PRBCs in 24 hours) at 16 level 1 trauma centers were reviewed. Transfusion ratios in the first 6 hours were correlated with outcome. RESULTS: All groups had similar baseline characteristics. Higher 6-hour ratios of FFP:PRBCs and PLTs:PRBCs lead to improved 6-hour mortality (from 37.3 [in the lowest ratio group] to 15.7 [in the middle ratio group] to 2.0% [in the highest ratio group] and 22.8% to 19.0% to 3.2%, respectively) and in-hospital mortality (from 54.9 to 41.1 to 25.5% and 43.7% to 46.8% to 27.4%, respectively). Initial higher ratios of FFP:PRBCs and PLTs:PRBCs decreased overall PRBC transfusion. CONCLUSIONS: The early administration of high ratios of FFP and platelets improves survival and decreases overall PRBC need in massively transfused patients. The largest difference in mortality occurs during the first 6 hours after admission, suggesting that the early administration of FFP and platelets is critical.

A highly porous silica and chitosan-based hemostatic dressing is superior in controlling hemorrhage in a severe groin injury model in swine.

BACKGROUND: This study compared the efficacy of 3 hemostatic dressings in a severe groin injury model in swine. METHODS: Twenty-three swine received TraumaStat (OreMedix, Lebanon, OR), Chitoflex (HemCon, Inc., Portland, OR), or standard gauze for hemostasis. Complete femoral vessel transections were followed by 30 seconds of uncontrolled hemorrhage. The groin was packed with the randomized dressing followed by 30 seconds of compression. Resuscitation with lactated Ringer's solution commenced immediately postcompression to the preinjury mean arterial blood pressure. Hemostasis failure was defined as blood pooling outside the wound. Animals were monitored and maintained at the preinjury mean arterial pressure for 120 minutes, culminating with euthanization. RESULTS: There were no differences in baseline values between groups. TraumaStat resulted in less hemostasis failure (P < .05), decreased postcompression blood loss (P < .05), and decreased fluid requirement (P < .05). No significant difference in mortality was seen between groups. There were no differences between standard gauze and Chitoflex with respect to dressing failure, posttreatment blood loss, or fluid resuscitation. CONCLUSIONS: TraumaStat performed significantly better than Chitoflex and standard gauze in controlling hemorrhage from a severe groin injury in swine.

Comparison of Petrifilm Staph Express Count System with the bacteriological analytical manual direct-plating method for enumeration of Staphylococcus aureus in artificially contaminated hard cheese.

The 3M Petrifilm Staph Express Count System was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) direct-plate count method for the enumeration of Staphylococcus aureus in 6 types of artificially contaminated hard cheese (Asiago, Cheddar, Gruyère, Parmesan, Romano, and Swiss). Five different samples of each cheese type were inoculated with S. aureus (ATCC 25923) to achieve low, medium, and high inoculum levels. S. aureus was enumerated by the Petrifilm and BAM methods, and the results were compared. Multivariate analysis of variance revealed no significant differences (P<0.05) between the 2 methods. The Petrifilm method compared favorably with the BAM procedure. The rapid method was more convenient to use, considerably faster, and less expensive to perform than the BAM method.

Amplatzer angled duct occluder for closure of patent ductus arteriosus larger than the aorta in an infant.

Transcatheter closure of patent ductus arteriosus (PDA) by Amplatzer duct occluder is the treatment of choice. However, closure of very large ducts in infants with low weight is a challenge for the interventionalist because a large device may obstruct the aorta or left pulmonary artery. Difficulty is also encountered in advancing the device around the curve of the right ventricular outflow tract toward the pulmonary artery; this curve is tight, more or less at a right angle in infants, leading to kinking of the sheath, which increases fluoroscopic time. This is the first reported case of a very large PDA (8.7 mm), larger than the aorta (8.2 mm), successfully closed by an Amplatzer angled duct occluder in an infant weighing 5 kg.

Use of an Amplatzer duct occluder for closing an aortico-left ventricular tunnel in a case of noncompaction of the left ventricle.

Aortico-left ventricular tunnel (ALVT) is a very rare congenital anomaly. Noncompaction of the left ventricle or "spongy myocardium" is another rare congenital cardiomyopathy. We report probably the first case in which these two rare anomalies causing pump failure coexisted in a 4-year-old make and the tunnel was successfully treated nonsurgically. Transcatheter closure of ALVT with the Amplatzer duct occluder is feasible and safe in a case of noncompaction of the LV with reduced LV function.

Lack of therapeutic effect of a specially designed yogurt for the eradication of Helicobacter pylori infection.

BACKGROUND: Current antibiotic treatment for Helicobacter pylori infection is often associated with frequent adverse effects and resistance to antibiotics. Alternative treatment methods to control H. pylori infection are needed. Some specific strains of lactic acid bacteria (probiotics) in dairy products are known to inhibit the growth of H. pylori in vitro. A clinical trial was conducted to see the efficacy of a specially designed yogurt product containing specific probiotics on the eradication of H. pylori. METHOD: The yogurt was prepared using three Lactobacillus spp. (L. acidophilus and L. casei) and one commercial starter culture (L. acidophilus, L. bulgaricus and Streptococcus thermophilus). All these cultures were previously evaluated, and found to have strong in vitro inhibitory effects on the growth of H. pylori. Twenty-seven asymptomatic women positive for H. pylori on gastric biopsy and 13C urea breath test were recruited, and administered 175 ml of the yogurt three times a day for 30 days. The 13C urea breath test was administered again, one month after stopping the yogurt treatment to detect the presence of H. pylori. RESULTS: In 26 of 27 subjects, the urea breath test values remained positive, indicating that the consumption of the yogurt had no effect on the eradication of H. pylori. CONCLUSION: Although the designed fermented milk containing lactobacilli is very effective in the inhibition of H. pylori growth in vitro, eradication of this infection in humans is difficult to achieve by consuming this product.