On the inclusion of forest exposure pathways into a stylized lake-farm scenario in a geological repository safety analysis

Geological disposal of radioactive waste has been recognized as the 'reference solution' to ensure the safety required for the present and future society and environment. To study the possible exposure pathways from groundwater to humans, radioactive transport modelling is used. One of the ecosystems that may play a significant role when assessing the dose conversion factor (i.e. the dose resulting from a nominal release of 1 Bq/year of each radionuclide) for humans is forest. In this paper we have developed a model of a lake-farm system with a forest component. The biosphere system used in this study represents a typical agricultural scenario in Finland, amended with a typical forest. A lake is assumed to form due to post-glacial land uplift. The main features of this future lake have been obtained from our probabilistic shoreline displacement model. Both deterministic calculations and sensitivity analysis were carried out to simulate the model. The deterministic simulation demonstrates the behaviour of the studied radionuclides (36Cl, 135Cs, 129I, 237Np, 90Sr, 99Tc and 238U) and the proportions of different exposure pathways to humans. Particularly for 135Cs and 129I, forest pathways make a notable contribution to the dose conversion factor. The sensitivity analysis was done using two methods: EFAST and Sobol'. With both methods, the parameters related to the farm contribute the most to the variance of the dose conversion factor for humans. The study demonstrates that the exposure pathways related to forest products may make a considerable contribution to the dose conversion factor in a lake-farm-forest system. It is also confirmed that an advanced sensitivity analysis for a radionuclide transport and dose assessment model on such a landscape scale is feasible even with moderate computational efforts.

Probabilistic assessment of the influence of lake properties in long-term radiation doses to humans

The assessment processes concerning the safety of nuclear waste repositories include the modelling of radionuclide transport in biosphere and the evaluation of the doses to the most affected humans. In this paper, a scenario, in which a contaminated lake is the water source for drinking water, irrigation water and watering of livestock, is presented. The objective of the paper is to probabilistically study the influence of lake properties as parameters in the assessment scenario. The properties of the lake are a result of previously conducted probabilistic studies, where the land uplift of the terrain surrounding the repositories and the formation of water bodies were studied in a 10,000-year time span using Monte Carlo simulation. The lake is formed at 3000 years from present day and the changing properties of the lake have been used in the study. The studied radionuclides ³⁶Cl, ¹³⁵Cs, ¹²⁹I, ²³⁷Np, ⁹⁰Sr, ⁹⁹Tc and ²³⁸U enter the lake with a rate of 1 Bq/year. The transport process from the lake water to humans is described and the doses (dose conversion factors) to adult humans are evaluated based on a study on average food consumption. Sensitivity analysis is used for identifying the parameters having the most influence on the outcome of the dose. Based on the results from the sensitivity analysis, the volumetric outflow rate of the lake and the volume of the lake were taken into closer consideration. The results show the influence of probabilistically derived geomorphic lake input parameters on the dose.

Does sagittal position of the CTDR-related centre of rotation influence functional outcome? Prospective 2-year follow-up analysis

PURPOSE

Recent studies describe significant rates of heterotopic ossification (HO) after cervical total disc replacement (CTDR). Little is known about the reasons, and one aspect that requires further in vivo investigation is the biomechanical alteration after CTDR and the role of the implant-related centre of rotation (CORi) in particular. The role of the sagittal position of the CORi on functional outcome in two versions of a semi-constrained disc prosthesis with sagittally different CORi is the topic of this study.

METHODS

Patients were candidates for single-level CTDR between C3 and C7 who suffered from CDDD and received a standard or flat version of activ C™ (Aesculap AG, Tuttlingen). Clinical and radiographic assessments were determined preoperatively, intraoperatively, at discharge and again at 6 weeks, 6 months, 1 and 2 years. Radiographic examinations were performed independently using specialized quantitative motion analysis software.

RESULTS

Clinical outcome improved significantly regarding NDI as well as VAS on neck and arm pain with no differences in mean improvement by study group. Segmental angle measures show a significantly better lordotic alignment for both groups after surgery, but the degree of correction achieved is higher in the flat group. Correlation analysis proves that the more anterior the CORi is positioned, the higher the lordotic correction is achieved (Pearson rho -0.385). Segmental ROM decreased in the standard group but was maintained for flat implants. At present, our data do not demonstrate a correlation between CORi and ROM at 2 years. Two years after surgery, severe HO grade III-IV was present in 31.6 % standard and 13.1 % flat cases with significant differences. Grouping according to HO severity showed comparable sagittal positions of CORi for flat implants but a more posterior position in the severe HO group for standard implants.

CONCLUSIONS

Our results confirm the influence of CORi location on segmental alignment, kinematics and HO for a semi-constrained CTDR, but it also indicates a multifactorial process.

Reduction of syndecan-1 expression is associated with dysplastic oral epithelium

Syndecans are a family of integral membrane proteoglycans that participate in cell-matrix interactions and growth factor binding. Syndecan-1 expression is induced during keratinocyte differentiation and reduced in squamous cell carcinomas. The purpose of this study was to examine the alteration in syndecan-1 expression in dysplastic oral epithelium. Sixty-six oral biopsy specimens (43 epithelial dysplasias, 3 carcinoma in situ and 20 squamous cell carcinomas) were studied using immunohistochemical methods. The normal epithelium specimens were highly positive for syndecan-1. Fifteen of 46 dysplasias or carcinoma in situ specimens showed negative or weak staining for syndecan-1, two of which were totally negative. Intermediate and strong staining were observed in 17 and 14 dysplasias or carcinoma in situ specimens, respectively. Thirteen (65%) squamous cell carcinomas showed negative or weak staining for syndecan-1, seven of which were totally negative. Only three carcinomas had a strong syndecan-1 expression. Four of the 34 patients with dysplasia who were followed up developed squamous cell carcinoma. All these dysplasias had weak or totally negative syndecan-1 expression. The results suggest that the loss of syndecan-1 is associated with dysplastic changes in oral epithelium.

Interstitial radiotherapy of 25 parasellar/clival meningiomas and 19 meningiomas in the elderly. Analysis of short-term tolerance and responses

I-125 seeds were permanently implanted into 25 parasellar-clival meningiomas (median age of patients, 56 y) and 19 globoid meningiomas in the elderly (median age of patients, 77 y) using stereotactic technique and 3-D dose planning. Total dose at the tumour margin was increased during the series from 100 Gy to 150 Gy. The procedure caused no mortality and no serious bleeding, but injury to the III cranial nerve due to puncture occurred in one (4%) of the 25 parasellar-clival meningiomas. In two (4.5%) of the 44 cases the postoperative CT scan showed a misplaced seed, located at the tumour surface. Nonenhancing hypodense rings developed around the seeds ('hot spots') with a median diameter of 10.5 mm at 12 months corresponding to a median initial activity of 8.7 mCi. In general, meningiomas responded by slow reduction in volume. The parasellar-clival meningiomas were followed-up for a median of 19 months (6-32), and so far 4 tumours have shrunk moderately, 13 slightly, and 5 not at all. Pre-operative III, V or VI cranial nerve signs were present in 17 patients and subsided in 8 of them. On the other hand, facial numbness developed or increased in 9 of the 25 patients, indicating that the V nerve is rather sensitive to this type of irradiation. In the 19 meningiomas of the elderly, the median follow-up time was 14 months (5-26). The median relative tumour volume was 46% at 12 months. Accounting for tumour-related deaths only, the actuarial survival rate was 78% at 12 months and 62% at 24 months. In general, brain oedema persisted despite reduction in tumour volume. Stereotactic implantation of I-125 seeds into intracranial meningiomas is relatively safe. Interstitial radiotherapy represents a potential tool in the control of medium-sized intracranial meningiomas with minimal brain oedema, but its long-term impact and untoward effects remain to be followed-up.

Alcohol as a risk factor for downhill skiing trauma

OBJECTIVE

To assess the role of alcohol in downhill skiing injuries.

DESIGN

Comparison of alcohol consumption habits and blood alcohol concentrations of injured skiers to those of randomly selected controls.

MATERIALS AND METHODS

121 injured skiers and 701 control subjects were interviewed and gave breath samples for the determination of blood alcohol concentration.

MEASUREMENTS AND MAIN RESULTS

Neither mean blood alcohol concentration nor the number of subjects with an intoxicating level of alcohol in blood (> 0.5 g/L; 2.9% of control subjects and 3.3% of the injured patients) differed significantly between the groups. Also, the severity of the injury and the blood alcohol concentration seemed to be independent of each other; all of the most severe traumas occurred in subjects with no detectable alcohol in blood.

CONCLUSIONS

Alcohol does not seem to be a major etiological factor in skiing-related injuries.

Determination of chlorhexidine in saliva using high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method for the determination of chlorhexidine in saliva is reported. The method developed includes a simple and short sample preparation with a one-step extraction procedure and a short total chromatographic run time of 5 min. In a preliminary pharmacokinetic study with a healthy volunteer the chlorhexidine concentration found in saliva after 12 h was 0.8 microgram/ml.

Determination of atropine and obidoxime in automatic injection devices used as antidotes against nerve agent intoxication

A capillary gas-liquid chromatographic (GLC) and an ion-pair high performance liquid chromatographic (HPLC) method were developed for the assay of atropine sulphate and obidoxime chloride from a parenteral solution in commercial automatic injection devices. The injectors are aimed for the emergency treatment of poisoning by nerve agents. The two-step GLC method consists of extraction of atropine as a free base prior to GLC analysis using scopolamine as an internal standard. Obidoxime is determined directly in a diluted sample solution by reversed-phase HPLC using sodium 1-heptanesulphonate as a counter ion in the mobile phase. The relative standard deviation (R.S.D.) was 1.81% for the GLC procedure with injectors containing only atropine and 2.37% for the GLC of atropine in atropine-obidoxime injectors. The R.S.D. for the HPLC procedure of obidoxime in atropine-obidoxime injectors was 0.82%. The corresponding R.S.D.s for the sampling of atropine-obidoxime injectors were 0.36% and 0.27%. The coefficient of determination (r2) was 1.000 for both methods. The recoveries at the target concentration averaged 101.0% and 98.7% with a standard error of the mean of 0.30 for both methods. The retention times for atropine and obidoxime were 6.27 and 4.29 min, respectively.

Genetic and psychosocial factors in schizophrenia: the Finnish Adoptive Family Study

A nationwide Finnish sample of schizophrenic mothers' offspring given up for adoption was compared blindly with matched controls (i.e., adopted-away offspring of nonschizophrenic biological parents). The offspring were born 1927-79. To date, a total of 247 adoptive families (112 index and 135 controls) have been investigated and rated. Of the 10 psychotic cases, 8 are offspring of schizophrenics and 2 are control offspring. However, no seriously disturbed offspring is found in a healthy or mildly disturbed adoptive family, and of those offspring who were psychotic or seriously disturbed, nearly all were reared in disturbed adoptive families. This supports the hypothesis that a possible genetic vulnerability has interacted with the adoptive rearing environment.

Interaction of genetic and psychosocial factors in schizophrenia

What the genetic and family dynamic theory have in common, is that the cause of schizophrenia could be found in the family. Usually the genetic factors and the rearing factors are confounded in the same family. In a study of adoptive children given away for adoption early enough, discrimination between these two sets of factors is possible. A nation-wide sample of offspring of schizophrenic mothers, given away for adoption, has been compared blindly with matched controls, i.e., adopted-away offspring of non-schizophrenic biologic parents. The families have been investigated thoroughly with joint and individual interviews and psychological tests. In the 91 pairs where both the index and control families have been investigated and rated so far, the total number of severe diagnoses (psychosis, borderline, character disorder) is 28.6% (26/91) in the index group and 16.5% (15/91) in the matched control group. Of the 7 psychotic cases, 6 are offspring of schizophrenics and only one a control offspring. The relation of psychopathology of adoptive families to the mental health ratings of the offspring supports the hypothesis that a possible genetic vulnerability has interacted with the adoptive rearing environment.

The Finnish adoptive family study of schizophrenia

A nationwide Finnish sample of schizophrenic mothers' offspring given up for adoption has been compared blindly with matched controls; i.e., adopted-away offspring of non-schizophrenic biologic parents. The families have been investigated thoroughly by joint and individual interviews and psychological tests. In the 91 pairs where both the index and control families have already been investigated and rated, the total number of severe diagnoses (psychosis, borderline, character disorder) is 28.6 percent (26/91) in the index group and 16.5 percent (15/91) in the matched control group. Of the seven psychotic cases, six are offspring of schizophrenics and only one is a control offspring. However, no seriously disturbed offspring has been found in a healthy or mildly disturbed adoptive family, and those offspring who were psychotic and seriously disturbed were nearly all reared in disturbed adoptive families. This combination of findings supports the hypothesis that a possible genetic vulnerability has interacted with the adoptive rearing environment.