Experimental Characterization and Quantification of Cement-Bentonite Interaction using Core Infiltration Techniques Coupled with X-ray Tomography

Deep geological storage of radioactive waste foresees cementitious materials as reinforcement of tunnels and as backfill. Bentonite is proposed to enclose spent fuel canisters and as drift seals. Sand/bentonite (s/b) is foreseen as backfill material of access galleries or as drift seals. The emplacement of cementitious material next to clay material generates an enormous chemical gradient in pore-water composition that drives diffusive solute transport. Laboratory studies and reactive transport modeling predicted significant mineral alteration at and near interfaces, mainly resulting in a decrease of porosity in bentonite. The goal of this thesis was to characterize and quantify the cement/bentonite interactions both spatially and temporally in laboratory experiments. A newly developed mobile X-ray transparent core infiltration device was used to perform X-ray computed tomography (CT) scans without interruption of running experiments. CT scans allowed tracking the evolution of the reaction plume and changes in core volume/diameter/density during the experiments. In total 4 core infiltration experiments were carried out for this study with the compacted and saturated cores consisting of MX-80 bentonite and sand/MX-80 bentonite mixture (s/b; 65/35%). Two different high-pH cementitious pore-fluids were infiltrated: a young (early) ordinary Portland cement pore-fluid (APWOPC; K+–Na+–OH-; pH 13.4; ionic strength 0.28 mol/kg) and a young ‘low-pH’ ESDRED shotcrete pore-fluid (APWESDRED; Ca2+–Na+–K+–formate; pH 11.4; ionic strength 0.11 mol/kg). The experiments lasted between 1 and 2 years. In both bentonite experiments, the hydraulic conductivity was strongly reduced after switching to high-pH fluids, changing eventually from an advective to a diffusion-dominated transport regime. The reduction was mainly induced by mineral precipitation and possibly partly also by high ionic strength pore-fluids. Both bentonite cores showed a volume reduction and a resulting transient flow in which pore-water was squeezed out during high-pH infiltration. The outflow chemistry was characterized by a high ionic strength, while chloride in the initial pore water got replaced as main anionic charge carrier by sulfate, originating from gypsum dissolution. The chemistry of the high-pH fluids got strongly buffered by the bentonite, consuming hydroxide and in case of APWESDRED also formate. Hydroxide got consumed by mineral reactions (saponite and possibly talc and brucite precipitation), while formate being affected by bacterial degradation. Post-mortem analysis showed reaction zones near the inlet of the bentonite core, characterized by calcium and magnesium enrichment, consisting predominately of calcite and saponite, respectively. Silica got enriched in the outflow, indicating dissolution of silicate-minerals, identified as preferentially cristobalite. In s/b, infiltration of APWOPC reduced the hydraulic conductivity strongly, while APWESDRED infiltration had no effect. The reduction was mainly induced by mineral precipitation and probably partly also by high ionic strength pore-fluids. Not clear is why the observed mineral precipitates in the APWESDRED experiment had no effect on the fluid flow. Both s/b cores showed a volume expansion along with decreasing ionic strengths of the outflow, due to mineral reactions or in case of APWESDRED infiltration also mediated by microbiological activity, consuming hydroxide and formate, respectively. The chemistry of the high-pH fluids got strongly buffered by the s/b. In the case of APWESDRED infiltration, formate reached the outflow only for a short time, followed by enrichment in acetate, indicating most likely biological activity. This was in agreement to post-mortem analysis of the core, observing black spots on the inflow surface, while the sample had a rotten-egg smell indicative of some sulfate reduction. Post-mortem analysis showed further in both cores a Ca-enrichment in the first 10 mm of the core due to calcite precipitation. Mg-enrichment was only observed in the APWOPC experiment, originating from newly formed saponite. Silica got enriched in the outflow of both experiments, indicating dissolution of silicate-minerals, identified in the OPC experiment as cristobalite. The experiments attested an effective buffering capacity for bentonite and s/b, a progressing coupled hydraulic-chemical sealing process and also the preservation of the physical integrity of the interface region in this setup with a total pressure boundary condition on the core sample. No complete pore-clogging was observed but the hydraulic conductivity got rather strongly reduced in 3 experiments, explained by clogging of the intergranular porosity (macroporosity). Such a drop in hydraulic conductivity may impact the saturation time of the buffer in a nuclear waste repository, although the processes and geometry will be more complex in repository situation.

Sudden cardiac death in forensic medicine – Swiss recommendations for a multidisciplinary approach

Sudden cardiac death (SCD) is by definition unexpected and cardiac in nature. The investigation is almost invariably performed by a forensic pathologist. Under these circumstances the role of the forensic pathologist is twofold: (1.) to determine rapidly and efficiently the cause and manner of death and (2.) to initiate a multidisciplinary process in order to prevent further deaths in existing family members. If the death is determined to be due to "natural" causes the district attorney in charge often refuses further examinations. However, additional examinations, i.e. extensive histopathological investigations and/or molecular genetic analyses, are necessary in many cases to clarify the cause of death. The Swiss Society of Legal Medicine created a multidisciplinary working group together with clinical and molecular geneticists and cardiologists in the hope of harmonising the approach to investigate SCD. The aim of this paper is to close the gap between the Swiss recommendations for routine forensic post-mortem cardiac examination and clinical recommendations for genetic testing of inherited cardiac diseases; this is in order to optimise the diagnostic procedures and preventive measures for living family members. The key points of the recommendations are (1.) the forensic autopsy procedure for all SCD victims under 40 years of age, (2.) the collection and storage of adequate samples for genetic testing, (3.) communication with the families, and (4.) a multidisciplinary approach including cardiogenetic counselling.

Intracoronary imaging of coronary atherosclerosis: validation for diagnosis, prognosis and treatment.

While coronary atherosclerosis is a leading cause of mortality, evaluation of coronary lesions was previously limited to either indirect angiographic assessment of the lumen silhouette or post mortem investigations. Intracoronary (IC) imaging modalities have been developed that allow for visualization and characterization of coronary atheroma in living patients. Used alone or in combination, these modalities have enhanced our understanding of pathobiological mechanisms of atherosclerosis, identified factors responsible for disease progression, and documented the ability of various medications to reverse the processes of plaque growth and destabilization. These methodologies have established a link between in vivo plaque characteristics and subsequent coronary events, thereby improving individual risk stratification, paving the way for risk-tailored systemic therapies and raising the option for pre-emptive interventions. Moreover, IC imaging is increasingly used during coronary interventions to support therapeutic decision-making in angiographically inconclusive disease, guide and optimize procedural results in selected lesion and patient subsets, and unravel mechanisms underlying stent failure. This review aims to summarize current evidence regarding the role of IC imaging for diagnosis and risk stratification of coronary atherosclerosis, and to describe its clinical role for guiding percutaneous coronary interventions. Future perspectives for in-depth plaque characterization using novel techniques and multimodality imaging approaches are also discussed.

Transmission of border disease virus from a persistently infected calf to seronegative heifers in early pregnancy

BACKGROUND: This study describes the transmission of border disease virus (BDV) from a persistently infected calf to seronegative heifers in early pregnancy, resulting in persistently infected fetuses. On day 50 of pregnancy (= day 0 of the infection phase), six heifers were co-housed in a free stall with a bull calf persistently infected with BDV (pi BVD) for 60 days. The heifers underwent daily clinical examination, and blood samples were collected regularly for detection of pestiviral RNA and anti-pestivirus antibodies. After day 60 (= day 110 of pregnancy), the heifers were slaughtered, and the fetuses and placentae underwent post-mortem and immunohistochemical examination and RT-PCR for viral RNA detection. RESULTS: Three heifers had mild viraemia from day 8 to day 14, and by day 40 all heifers had pestivirus antibodies identified as anti-BDV antibodies in the serum neutralisation test. The placenta of the three viraemic heifers had histological evidence of inflammation, and fetal organs from these heifers were positive for pestivirus antigen by immunohistochemical examination and for BD viral RNA by RT-PCR and sequencing. Thus, co-housing of heifers in early pregnancy with a pi-BDV calf led to seroconversion in all heifers and persistent fetal infection in three. CONCLUSIONS: Considering that pi-BDV cattle can infect other cattle and lead to persistent infection of the fetus in pregnant cows, BDV should not be ignored in the context of the mandatory BVDV eradication and monitoring program. This strongly suggests that BDV should be taken into account in BVD eradication and control programs.

Postmortem magnetic resonance imaging: Reproducing typical autopsy heart measurements

PURPOSE The aim of this study was to evaluate the utility of cardiac postmortem magnetic resonance (PMMR) to perform routine measurements of the ventricular wall thicknesses and the heart valves and to assess if imaging measurements are consistent with traditional autopsy measurements. METHODS In this retrospective study, 25 cases with cardiac PMMR and subsequent autopsy were included. The thicknesses of the myocardial walls as well as the circumferences of all heart valves were measured on cardiac PMMR and compared to autopsy measurements. Paired samples T-test and the Wilcoxon-Signed rank test, were used to compare autopsy and cardiac PMMR measurements. For exploring correlations, the Pearson's Correlation coefficient and the Spearman's Rho test were used. RESULTS Cardiac PMMR measurements of the aortic and pulmonary valve circumferences showed no significant differences from autopsy measurements. The mitral and tricuspid valves circumferences differed significantly from autopsy measurements. Left myocardial and right myocardial wall thickness also differed significantly from autopsy measurements. Left and right myocardial wall thickness, and tricuspid valve circumference measurements on cardiac PMMR and autopsy, correlated strongly and significantly. CONCLUSION Several PMMR measurements of cardiac parameters differ significantly from corresponding autopsy measurements. However, there is a strong correlation between cardiac PMMR measurements and autopsy measurements in the majority of these parameters. It is important to note that myocardial walls are thicker when measured in situ on cardiac PMMR than when measured at autopsy. Investigators using post-mortem MR should be aware of these differences in order to avoid false diagnoses of cardiac pathology based on cardiac PMMR.

Dissolution-Precipitation in Porous Media: Experiments and Modelling

The evolution of porosity due to dissolution/precipitation processes of minerals and the associated change of transport parameters are of major interest for natural geological environments and engineered underground structures. We designed a reproducible and fast to conduct 2D experiment, which is flexible enough to investigate several process couplings implemented in the numerical code OpenGeosys-GEM (OGS-GEM). We investigated advective-diffusive transport of solutes, effect of liquid phase density on advective transport, and kinetically controlled dissolution/precipitation reactions causing porosity changes. In addition, the system allowed to investigate the influence of microscopic (pore scale) processes on macroscopic (continuum scale) transport. A Plexiglas tank of dimension 10 × 10 cm was filled with a 1 cm thick reactive layer consisting of a bimodal grain size distribution of celestite (SrSO4) crystals, sandwiched between two layers of sand. A barium chloride solution was injected into the tank causing an asymmetric flow field to develop. As the barium chloride reached the celestite region, dissolution of celestite was initiated and barite precipitated. Due to the higher molar volume of barite, its precipitation caused a porosity decrease and thus also a decrease in the permeability of the porous medium. The change of flow in space and time was observed via injection of conservative tracers and analysis of effluents. In addition, an extensive post-mortem analysis of the reacted medium was conducted. We could successfully model the flow (with and without fluid density effects) and the transport of conservative tracers with a (continuum scale) reactive transport model. The prediction of the reactive experiments initially failed. Only the inclusion of information from post-mortem analysis gave a satisfactory match for the case where the flow field changed due to dissolution/precipitation reactions. We concentrated on the refinement of post-mortem analysis and the investigation of the dissolution/precipitation mechanisms at the pore scale. Our analytical techniques combined scanning electron microscopy (SEM) and synchrotron X-ray micro-diffraction/micro-fluorescence performed at the XAS beamline (Swiss Light Source). The newly formed phases include an epitaxial growth of barite micro-crystals on large celestite crystals (epitaxial growth) and a nano-crystalline barite phase (resulting from the dissolution of small celestite crystals) with residues of celestite crystals in the pore interstices. Classical nucleation theory, using well-established and estimated parameters describing barite precipitation, was applied to explain the mineralogical changes occurring in our system. Our pore scale investigation showed limits of the continuum scale reactive transport model. Although kinetic effects were implemented by fixing two distinct rates for the dissolution of large and small celestite crystals, instantaneous precipitation of barite was assumed as soon as oversaturation occurred. Precipitation kinetics, passivation of large celestite crystals and metastability of supersaturated solutions, i.e. the conditions under which nucleation cannot occur despite high supersaturation, were neglected. These results will be used to develop a pore scale model that describes precipitation and dissolution of crystals at the pore scale for various transport and chemical conditions. Pore scale modelling can be used to parameterize constitutive equations to introduce pore-scale corrections into macroscopic (continuum) reactive transport models. Microscopic understanding of the system is fundamental for modelling from the pore to the continuum scale.

First detection of sarcoptic mange in free-ranging wild boar (Sus scrofa) in Switzerland.

In Switzerland sarcoptic mange is frequent in free-ranging wild carnivores but until recent years no cases had been recorded in wild ungulates. Since 2010, cases have been observed in wild boar in the cantons of Solothurn, Tessin and Thurgau. Here, we report the detection of mange-like skin lesions in wild boars by photo-trapping and the post-mortem findings in 6 culled animals presenting different stages of the disease. Potential sources of infection include mangy red foxes, outdoor domestic pigs and wild boars from surrounding countries. Disease spread in the wild boar population may become relevant not only for wildlife but also for domestic pig health in the future if piggeries' biosecurity is insufficient to prevent interactions with wild boar.

A simulation study on the statistical monitoring of condemnation rates from slaughterhouses for syndromic surveillance: an evaluation based on Swiss data

Syndromic surveillance (SyS) systems currently exploit various sources of health-related data, most of which are collected for purposes other than surveillance (e.g. economic). Several European SyS systems use data collected during meat inspection for syndromic surveillance of animal health, as some diseases may be more easily detected post-mortem than at their point of origin or during the ante-mortem inspection upon arrival at the slaughterhouse. In this paper we use simulation to evaluate the performance of a quasi-Poisson regression (also known as an improved Farrington) algorithm for the detection of disease outbreaks during post-mortem inspection of slaughtered animals. When parameterizing the algorithm based on the retrospective analyses of 6 years of historic data, the probability of detection was satisfactory for large (range 83-445 cases) outbreaks but poor for small (range 20-177 cases) outbreaks. Varying the amount of historical data used to fit the algorithm can help increasing the probability of detection for small outbreaks. However, while the use of a 0·975 quantile generated a low false-positive rate, in most cases, more than 50% of outbreak cases had already occurred at the time of detection. High variance observed in the whole carcass condemnations time-series, and lack of flexibility in terms of the temporal distribution of simulated outbreaks resulting from low reporting frequency (monthly), constitute major challenges for early detection of outbreaks in the livestock population based on meat inspection data. Reporting frequency should be increased in the future to improve timeliness of the SyS system while increased sensitivity may be achieved by integrating meat inspection data into a multivariate system simultaneously evaluating multiple sources of data on livestock health.

Behavioral Implications of Knockout for the Dyslexia-Risk Gene Dcdc2 in Mice

Several genetic linkage and epidemiological studies have provided strong evidence that DCDC2 is a candidate gene for developmental dyslexia, a disorder that impairs a person’s reading ability despite adequate intelligence, education, and socio-economic status. Studies investigating embryonic intra-ventricular RNA interference (RNAi) of Dcdc2, a rat homolog of the DCDC2 gene in humans, indicate disruptions in neuronal migration in the rat cortex during development. Interestingly, these anatomical anomalies are consistent with post mortem histological analysis of human dyslexic patients. Other rodent models of cortical developmental disruption have shown impairment in rapid auditory processing and learning maze tasks in affected subjects. The current study investigates the rapid auditory processing abilities of mice heterozygous for Dcdc2 (one functioning Dcdc2 allele) and mice with a homozygous knockout of Dcdc2 (no functioning Dcdc2 allele). It is important to note that this genetic model for behavioral assessment is still in the pilot stage. However, preliminary results suggest that mice with a genetic mutation of Dcdc2 have impaired rapid auditory processing, as well as non-spatial maze learning and memory ability, as compared to wildtypes. By genetically knocking out Dcdc2 in mice, behavioral features associated with Dcdc2 can be characterized, along with other neurological abnormalities that may arise due to the loss of the functioning gene.

Knockdown of Kiaa0319 Reduces Dendritic Spine Density

Developmental Dyslexia is a reading disorder that affects individuals that possess otherwise normal intelligence. Until the four candidate dyslexia susceptibility genes were discovered, the cause of cortical malformations found in post mortem dyslexic brains was unclear. Normal brain development is crucial for the proper wiring of the neural circuitry that allow an individual to perform cognitive tasks like reading. For years, familial and twin studies have suggested that there was a genetic basis to the causation of dyslexia. Kiaa0319 was among the candidate dyslexia susceptibility genes that were ascertained. KIAA0319 is located on Chromosome 6p22.2-22.3 and has been found to exhibit differential spatial-temporal expression patterns in the brain throughout development, which suggests that the polycystic kidney disease (PKD) domain encoded by KIAA0319 facilitates cell-cell adhesion to enable neuronal precursors to crawl up the radial glia during neuronal migration. With the knowledge of KIAA0319 involvement in early neurogenesis, we were interested in determining how different KIAA0319 expression may impact cortical neurons in layer II and III during early adulthood. We show that KIAA0319 knockdown in cortical pyramidal neurons significantly reduces the dendritic spine density. Studies have shown that changes in dendritic spine morphology and density affect properties of neural circuitry. Henceforth, this finding may reveal a link between the Kiaa0319 gene and the deficit of the neural processing task of reading due to reduced spines density. Finding a correlation between Kiaa0319 expression and its influence on dendritic spine development may lead to a greater insight of a direct link between the dyslexia susceptibility gene and the biological mechanism that causes dyslexia.

AVIAN ROTAVIRUSES

The prevalence of antirotavirus antibodies in chickens and turkeys in the Gonzales, Texas and Llano, Texas areas was studied. Caged layer chicken flocks were found to have a prevalence of 64% when samples were taken randomly. This compares to 45% in chicken broiler breeder flocks and 92% in turkey breeding flocks. The natural occurrence of turkey rotavirus infection in two separate field studies showed an increase in mortality varying from 9% to 45% above expected death losses. Clinically, pasted vents, lacitude, and general malaise were noted in affected poults. Lesions noted on post mortem examination were; slight ballooning of the small intestine, excessively large ceca, and mild hyperemia of the small and large intestines.^ The use of maternal antibody from simian rotavirus immunized chickens' eggs for preventing murine rotavirus infection in infant mice was investigated. There was a reduction from 91% to 15% incidence when infant mice were treated twice daily with egg yolk immunoglobulin.^ The need for a convenient, easily grown and rapidly reproducing model for avian and mammalian rotaviruses led to the use of coturnix chicks. The turkey rotavirus was adapted to the quail chicks be serial passage. Transmission and scanning electron microscopy as well as micropathological methods were used in the study of the pathogenesis of rotavirus infection in quail and infant mice. ^

Cary's Illustrated and Priced Catalogue: Surgical Instruments, Physicians, Hospital Supplies, and Furnishings, Druggist Sundries, Etc.

Second Edition. Pp.5-61 General Surgical Necessities, Gauze, Antiseptic Sundries, Surgical Sundries, Rubber Bandages, Catheters, Bougies, Splints, Tents, Emergency Bags, Surgeon's Needles, Operating Instruments, Amputating, Forceps, Aspiration, Cases, Catheters and Directors, Pocket Case Instruments, Dissecting and Post-Mortem Pp.62-118 General Operating - Osteotomy, Mastoid, Trephining, Eye Instruments, Aural, Nasal, Mouth and Throat, Tooth Forceps, Laryngoscopic Sets, Hydraulic Air Compressor, Variocele, Genito Urinary Pp. 119-167 Genito Urinary-Lithotrity, Alimentary, Anal and Rectal, Gynaecological, Pessaries, Microscopes, Syringes Pp.168-205 Chemical Apparatus and Glassware, Physician's Cabinets, Office Furniture, Operating Chairs and Tables, Hospital Beds, Cautery, Electrolytic, Batteries Pp.206-246 Cases, Varicose, Braces, Abdominal Supporters, Trusses, Invalid Chairs and Supplies, Sterilizers, Saddle-Bags, Deformity Apparatus Advertisements: Bandages, Abdominal Supporters, Rubber Supplies, Bags, Batteries, Cotton, Microscopes, Hypodermic Tablets, Atomizers, Furniture, Sterilizers, Syringes

Illustrated Catalogue of Standard Surgical Instruments and Allied Lines

Section "A": Dissecting and Post-Mortem Instruments Diagnostic Instruments and Apparatus Microscopes and Microscopic Accessories Laboratory Apparatus and Glass Ware Apparatus for Blood and Urine Analysis Apparatus for Phlebotomy, Cupping and Leeching Apparatus for Infusion and Transfusion Syringes for Aspiration and Injection Osteological Preparations Section "B": Anaesthetic, General Operating, Osteotomy, Trepanning, Bullet, Pocket Case, Cautery, Ligatures, Sutures, Dressings, Etc. Section "B" continued Section "C": Eye, Ear, Nasal, Dermal, Oral, Tonsil, Tracheal, Laryngeal,Esophageal, Stomach, Intestinal, Gall Bladder Section "C": continued Section "D": Rectal, Phimosis, Prostatic, Vesical, Urethral, Ureteral, Instruments Section "E": Gynecic, Hysterectomy, Obstetrical, Instrument Satchels, Medicine Cases Section "F": Electric Cautery Transformers, Electro-Cautery Burners and Accessories, Electric Current Controllers, Electro-Diagnostic Outfits, Electrolysis Instruments Electro-Therapeutic Lamps, Faradic Batteries, Galvanic Batteries Section "G": Office Furniture, Office Sterilizing Apparatus, Hospital Supplies, Surgical Rubber Goods, Sick Room Utensils, Invalid Rolling Chairs, Invalid Supplies Section "H": Artificial Limbs, Deformity Apparatus, Fracture Apparatus, Splints, Splint Material, Elastic Hosiery, Abdominal Supporters, Crutches, Trusses, Suspensories, Etc. Index

Northwards and eastwards velocities extracted from a historical run (for the year 2000) of the UVic Earth System Climate Model of Weaver et al. (2001)

This study provides a theoretical assessment of the potential bias due to differential lateral transport on multi-proxy studies based on a range of marine microfossils. Microfossils preserved in marine sediments are at the centre of numerous proxies for paleoenvironmental reconstructions. The precision of proxies is based on the assumption that they accurately represent the overlying watercolumn properties and faunas. Here we assess the possibility of a syn-depositional bias in sediment assemblages caused by horizontal drift in the water column, due to differential settling velocities of sedimenting particles based on their shape, size and density, and due to differences in current velocities. Specifically we calculate the post-mortem lateral transport undergone by planktic foraminifera and a range of other biological proxy carriers (diatoms, radiolaria and fecal pellets transporting coccolithophores) in several regions with high current velocities. We find that lateral transport of different planktic foraminiferal species is minimal due to high settling velocities. No significant shape- or size-dependent sorting occurs before reaching the sediment, making planktic foraminiferal ideal proxy carriers. In contrast, diatoms, radiolaria and fecal pellets can be transported up to 500km in some areas. For example in the Agulhas current, transport can lead to differences of up to 2°C in temperature reconstructions between different proxies in response to settling velocities. Therefore, sediment samples are likely to contain different proportions of local and imported particles, decreasing the precision of proxies based on these groups and the accuracy of the temperature reconstruction.

Patrimonio y producción en los entornos rurales de Buenos Aires. San José de Flores, 1800-1875

En el presente artículo reconstruimos a partir de la información proporcionada por testamentos e inventarios post mortem las características productivas de los establecimientos frutihortícolas y cerealeros del partido de San José de Flores. Abordamos, además, el estudio de los esquemas de inversión de los propietarios y/o arrendatarios de estas unidades esbozando su perfil socioeconómico y político, deteniéndonos especialmente en aquellos que han accedido a la propiedad legal de los terrenos.