Forensic application of postmortem diffusion-weighted and diffusion tensor MR imaging of the human brain in situ

DWI and DTI of the brain have proved to be useful in many neurologic disorders and in traumatic brain injury. This prospective study aimed at the evaluation of the influence of the PMI and the cause of death on the ADC and FA for the application of DWI and DTI in forensic radiology.

Different cardiac biomarkers to detect peri-procedural myocardial infarction in contemporary coronary stent trials: impact on outcome reporting

To assess the differential implications of cardiac biomarker type on peri-procedural myocardial infarction (PMI) reporting.

Cadaver dogs--a study on detection of contaminated carpet squares

INTRODUCTION: Cadaver dogs are known as valuable forensic tools in crime scene investigations. Scientific research attempting to verify their value is largely lacking, specifically for scents associated with the early postmortem interval. The aim of our investigation was the comparative evaluation of the reliability, accuracy, and specificity of three cadaver dogs belonging to the Hamburg State Police in the detection of scents during the early postmortem interval. MATERIAL AND METHODS: Carpet squares were used as an odor transporting media after they had been contaminated with the scent of two recently deceased bodies (PMI<3h). The contamination occurred for 2 min as well as 10 min without any direct contact between the carpet and the corpse. Comparative searches by the dogs were performed over a time period of 65 days (10 min contamination) and 35 days (2 min contamination). RESULTS: The results of this study indicate that the well-trained cadaver dog is an outstanding tool for crime scene investigation displaying excellent sensitivity (75-100), specificity (91-100), and having a positive predictive value (90-100), negative predictive value (90-100) as well as accuracy (92-100).

Statistical evaluation of time-dependent metabolite concentrations: estimation of post-mortem intervals based on in situ 1H-MRS of the brain

Knowledge of the time interval from death (post-mortem interval, PMI) has an enormous legal, criminological and psychological impact. Aiming to find an objective method for the determination of PMIs in forensic medicine, 1H-MR spectroscopy (1H-MRS) was used in a sheep head model to follow changes in brain metabolite concentrations after death. Following the characterization of newly observed metabolites (Ith et al., Magn. Reson. Med. 2002; 5: 915-920), the full set of acquired spectra was analyzed statistically to provide a quantitative estimation of PMIs with their respective confidence limits. In a first step, analytical mathematical functions are proposed to describe the time courses of 10 metabolites in the decomposing brain up to 3 weeks post-mortem. Subsequently, the inverted functions are used to predict PMIs based on the measured metabolite concentrations. Individual PMIs calculated from five different metabolites are then pooled, being weighted by their inverse variances. The predicted PMIs from all individual examinations in the sheep model are compared with known true times. In addition, four human cases with forensically estimated PMIs are compared with predictions based on single in situ MRS measurements. Interpretation of the individual sheep examinations gave a good correlation up to 250 h post-mortem, demonstrating that the predicted PMIs are consistent with the data used to generate the model. Comparison of the estimated PMIs with the forensically determined PMIs in the four human cases shows an adequate correlation. Current PMI estimations based on forensic methods typically suffer from uncertainties in the order of days to weeks without mathematically defined confidence information. In turn, a single 1H-MRS measurement of brain tissue in situ results in PMIs with defined and favorable confidence intervals in the range of hours, thus offering a quantitative and objective method for the determination of PMIs.

Hierarchical segmentation-assisted multimodal registration for MR brain images

Information theory-based metric such as mutual information (MI) is widely used as similarity measurement for multimodal registration. Nevertheless, this metric may lead to matching ambiguity for non-rigid registration. Moreover, maximization of MI alone does not necessarily produce an optimal solution. In this paper, we propose a segmentation-assisted similarity metric based on point-wise mutual information (PMI). This similarity metric, termed SPMI, enhances the registration accuracy by considering tissue classification probabilities as prior information, which is generated from an expectation maximization (EM) algorithm. Diffeomorphic demons is then adopted as the registration model and is optimized in a hierarchical framework (H-SPMI) based on different levels of anatomical structure as prior knowledge. The proposed method is evaluated using Brainweb synthetic data and clinical fMRI images. Both qualitative and quantitative assessment were performed as well as a sensitivity analysis to the segmentation error. Compared to the pure intensity-based approaches which only maximize mutual information, we show that the proposed algorithm provides significantly better accuracy on both synthetic and clinical data.

Rigor mortis at the myocardium investigated by post-mortem magnetic resonance imaging

INTRODUCTION Post-mortem cardiac MR exams present with different contraction appearances of the left ventricle in cardiac short axis images. It was hypothesized that the grade of post-mortem contraction may be related to the post-mortem interval (PMI) or cause of death and a phenomenon caused by internal rigor mortis that may give further insights in the circumstances of death. METHOD AND MATERIALS The cardiac contraction grade was investigated in 71 post-mortem cardiac MR exams (mean age at death 52y, range 12-89y; 48 males, 23 females). In cardiac short axis images the left ventricular lumen volume as well as the left ventricular myocardial volume were assessed by manual segmentation. The quotient of both (LVQ) represents the grade of myocardial contraction. LVQ was correlated to the PMI, sex, age, cardiac weight, body mass and height, cause of death and pericardial tamponade when present. In cardiac causes of death a separate correlation was investigated for acute myocardial infarction cases and arrhythmic deaths. RESULTS LVQ values ranged from 1.99 (maximum dilatation) to 42.91 (maximum contraction) with a mean of 15.13. LVQ decreased slightly with increasing PMI, however without significant correlation. Pericardial tamponade positively correlated with higher LVQ values. Variables such as sex, age, body mass and height, cardiac weight and cause of death did not correlate with LVQ values. There was no difference in LVQ values for myocardial infarction without tamponade and arrhythmic deaths. CONCLUSION Based on the observation in our investigated cases, the phenomenon of post-mortem myocardial contraction cannot be explained by the influence of the investigated variables, except for pericardial tamponade cases. Further research addressing post-mortem myocardial contraction has to focus on other, less obvious factors, which may influence the early post-mortem phase too.

Smaller but denser: postmortem changes alter the CT characteristics of subdural hematomas

PURPOSE The aim of this study was to investigate if (1) the volume of subdural hematomas (SDH), midline shift, and CT density of subdural hematomas are altered by postmortem changes and (2) if these changes are dependent on the postmortem interval (PMI). MATERIALS AND METHODS Ante mortem computed tomography (AMCT) of the head was compared to corresponding postmortem CT (PMCT) in 19 adults with SDH. SDH volume, midline shift, and hematoma density were measured on both AMCT and PMCT and their differences assessed using Wilcoxon-Signed Rank Test. Spearman's Rho Test was used to assess significant correlations between the PMI and the alterations of SDH volume, midline shift, and hematoma density. RESULTS Mean time between last AMCT and PMCT was 109 h, mean PMI was 35 h. On PMCT mean midline displacement was decreased by 57% (p < 0.001); mean SDH volume was decreased by 38% (p < 0.001); and mean hematoma density was increased by 18% (p < 0.001) in comparison to AMCT. There was no correlation between the PMI and the normalization of the midline shift (p = 0.706), the reduction of SDH volume (p = 0.366), or the increase of hematoma density (p = 0.140). CONCLUSIONS This study reveals that normal postmortem changes significantly affect the extent and imaging characteristics of subdural hematoma and may therefore affect the interpretation of these findings on PMCT. Radiologists and forensic pathologists who use PMCT must be aware of these phenomena in order to correctly interpret PMCT findings in cases of subdural hemorrhages.

How often parametrial involvement leads to post-operative adjuvant treatment in locally advanced cervical cancer after neoadjuvant chemotherapy and type C radical hysterectomy?

OBJECTIVE Parametrial involvement (PMI) is one of the most important factors influencing prognosis in locally advanced stage cervical cancer (LACC) patients. We aimed to evaluate PMI rate among LACC patients undergoing neoadjuvant chemotherapy (NACT), thus evaluating the utility of parametrectomy in tailor adjuvant treatments. METHODS Retrospective evaluation of consecutive 275 patients affected by LACC (IB2-IIB), undergoing NACT followed by type C/class III radical hysterectomy. Basic descriptive statistics, univariate and multivariate analyses were applied in order to identify factors predicting PMI. Survival outcomes were assessed using Kaplan-Meier and Cox models. RESULTS PMI was detected in 37 (13%) patients: it was associated with vaginal involvement, lymph node positivity and both in 10 (4%), 5 (2%) and 12 (4%) patients, respectively; while PMI alone was observed in only 10 (4%) patients. Among this latter group, adjuvant treatment was delivered in 3 (1%) patients on the basis of pure PMI; while the remaining patients had other characteristics driving adjuvant treatment. Considering factors predicting PMI we observed that only suboptimal pathological responses (OR: 1.11; 95% CI: 1.01, 1.22) and vaginal involvement (OR: 1.29 (95%) CI: 1.17, 1.44) were independently associated with PMI. PMI did not correlate with survival (HR: 2.0; 95% CI: 0.82, 4.89); while clinical response to NACT (HR: 3.35; 95% CI: 1.59, 7.04), vaginal involvement (HR: 2.38; 95% CI: 1.12, 5.02) and lymph nodes positivity (HR: 3.47; 95% CI: 1.62, 7.41), independently correlated with worse survival outcomes. CONCLUSIONS Our data suggest that PMI had a limited role on the choice to administer adjuvant treatment, thus supporting the potential embrace of less radical surgery in LACC patients undergoing NACT. Further prospective studies are warranted.

Redlining, the Community Reinvestment Act, and Private Mortgage Insurance

This paper examines whether neighborhood racial or income composition influences a lender's treatment of mortgage applications. Recent studies have found little evidence of differential treatment based on either the racial or income composition of the neighborhood, once the specification accounts for neighborhood risk factors. This paper suggests that lenders may favor applicants from CRA-protected neighborhoods if they obtain Private Mortgage Insurance (PMI) and that this behavior may mask lender redlining of low income and minority neighborhoods. For loan applicants who are not covered by PMI, this paper finds strong evidence that applications for units in low-income neighborhoods are less likely to be approved, and some evidence that applications for units in minority neighborhoods are less likey to be approved, regardless of the race of the applicant. This pattern is not visible in earlier studies because lenders appear to treat applications from these neighborhoods more favorably when the applicant obtains PMI.

Isotopic signature of specific biomarkers derived from anaerobic methanotrophic archaea (ANME groups) and sulphate-reducing bacteria (SRB) at different cold seep provinces

Anaerobic methane-oxidizing microbial communities in sediments at cold methane seeps are important factors in controlling methane emission to the ocean and atmosphere. Here, we investigated the distribution and carbon isotopic signature of specific biomarkers derived from anaerobic methanotrophic archaea (ANME groups) and sulphate-reducing bacteria (SRB) responsible for the anaerobic oxidation of methane (AOM) at different cold seep provinces of Hydrate Ridge, Cascadia margin. The special focus was on their relation to in situ cell abundances and methane turnover. In general, maxima in biomarker abundances and minima in carbon isotope signatures correlated with maxima in AOM and sulphate reduction as well as with consortium biomass. We found ANME-2a/DSS aggregates associated with high abundances of sn-2,3-di-O-isoprenoidal glycerol ethers (archaeol, sn-2-hydroxyarchaeol) and specific bacterial fatty acids (C16:1omega5c, cyC17:0omega5,6) as well as with high methane fluxes (Beggiatoa site). The low to medium flux site (Calyptogena field) was dominated by ANME-2c/DSS aggregates and contained less of both compound classes but more of AOM-related glycerol dialkyl glycerol tetraethers (GDGTs). ANME-1 archaea dominated deeper sediment horizons at the Calyptogena field where sn-1,2-di-O-alkyl glycerol ethers (DAGEs), archaeol, methyl-branched fatty acids (ai-C15:0, i-C16:0, ai-C17:0), and diagnostic GDGTs were prevailing. AOM-specific bacterial and archaeal biomarkers in these sediment strata generally revealed very similar d13C-values of around -100 per mill. In ANME-2-dominated sediment sections, archaeal biomarkers were even more 13C-depleted (down to -120 per mill), whereas bacterial biomarkers were found to be likewise 13C-depleted as in ANME-1-dominated sediment layers (d13C: -100 per mill). The zero flux site (Acharax field), containing only a few numbers of ANME-2/DSS aggregates, however, provided no specific biomarker pattern. Deeper sediment sections (below 20 cm sediment depth) from Beggiatoa covered areas which included solid layers of methane gas hydrates contained ANME-2/DSS typical biomarkers showing subsurface peaks combined with negative shifts in carbon isotopic compositions. The maxima were detected just above the hydrate layers, indicating that methane stored in the hydrates may be available for the microbial community. The observed variations in biomarker abundances and 13C-depletions are indicative of multiple environmental and physiological factors selecting for different AOM consortia (ANME-2a/DSS, ANME-2c/DSS, ANME-1) along horizontal and vertical gradients of cold seep settings.

Chemical and isotopic analysis of bulk organic matter and hydrocarbon biomarkers from IODP Holes 311-U1327C, 311-U1328B and 311-U1328C

The chemical and isotopic compositions of sedimentary organic matter (SOM) from two mid-slope sites of the northern Cascadia margin were investigated during Integrated Ocean Drilling Program (IODP) Expedition 311 to elucidate the organic matter origins and identify potential microbial contributions to SOM. Gas hydrate is present at both locations (IODP Sites U1327 and U1328), with distinct patterns of near-seafloor structural accumulations at the cold seep Site U1328 and deeper stratigraphic accumulations at the slope-basin Site U1327. Source characterization and evidence that some components of the organic matter have been diagenetically altered are determined from the concentrations and isotopic compositions of hydrocarbon biomarkers, total organic carbon (TOC), total nitrogen (TN) and total sulfur (TS). The carbon isotopic compositions of TOC (d13C TOC = -26 to -22 per mil) and long-chain n-alkanes (C27, C29 and C31, d13C = -34 to -29 per mil) suggest the organic matter at both sites is a mixture of 1) terrestrial plants that employ the C3 photosynthetic pathway and 2) marine algae. In contrast, the d15N TN values of the bulk sediment (+4 to +8 per mil) are consistent with a predominantly marine source, but these values most likely have been modified during microbial organic matter degradation. The d13C values of archaeal biomarker pentamethylicosane (PMI) (-46.4 per mil) and bacterial-sourced hopenes, diploptene and hop-21-ene (-40.9 to -34.7 per mil) indicate a partial contribution from methane carbon or a chemoautotrophic pathway. Our multi-isotope and biomarker-based conclusions are consistent with previous studies, based only on the elemental composition of bulk sediments, that suggested a mixed marine-terrestrial organic matter origin for these mid-slope sites of the northern Cascadia margin.

Stable isotope analysis and biomarkers of carbonates from the Columbia River in southwestern Washington, USA

Exotic limestone masses with silicified fossils, enclosed within deep-water marine siliciclastic sediments of the Early to Middle Miocene Astoria Formation, are exposed along the north shore of the Columbia River in southwestern Washington, USA. Samples from four localities were studied to clarify the origin and diagenesis of these limestone deposits. The bioturbated and reworked limestones contain a faunal assemblage resembling that of modern and Cenozoic deep-water methane-seeps. Five phases make up the paragenetic sequence: (1) micrite and microspar; (2) fibrous, banded and botryoidal aragonite cement, partially replaced by silica or recrystallized to calcite; (3) yellow calcite; (4) quartz replacing carbonate phases and quartz cement; and (5) equant calcite spar and pseudospar. Layers of pyrite frequently separate different carbonate phases and generations, indicating periods of corrosion. Negative d13Ccarbonate values as low as -37.6 per mill V-PDB reveal an uptake of methane-derived carbon. In other cases, d13Ccarbonate values as high as 7.1 per mill point to a residual, 13C-enriched carbon pool affected by methanogenesis. Lipid biomarkers include 13C-depleted, archaeal 2,6,10,15,19-pentamethylicosane (PMI; d13C: -128 per mill), crocetane and phytane, as well as various iso- and anteiso-carbon chains, most likely derived from sulphate-reducing bacteria. The biomarker inventory proves that the majority of the carbonates formed as a consequence of sulphate-dependent anaerobic oxidation of methane. Silicification of fossils and early diagenetic carbonate cements as well as the precipitation of quartz cement - also observed in other methane-seep limestones enclosed in sediments with abundant diatoms or radiolarians - is a consequence of a preceding increase of alkalinity due to anaerobic oxidation of methane, inducing the dissolution of silica skeletons. Once anaerobic oxidation of methane has ceased, the pH drops again and silica phases can precipitate.

Contents and stable carbon isotope compositions of biomarkers indicative for AOM-communities dominated by different ANME groups in two carbonate samples from Hydrate Hole pockmark

Different types of seep carbonates were recovered from the 'Kouilou pockmarks' on the Congo deep-sea fan in approximately 3100 m water depth. The carbonate aggregates are represented by pyritiferous nodules, crusts and slabs, tubes, and filled molds. The latter are interpreted to represent casts of former burrows of bivalves and holothurians. The nodules consisting of high-Mg-calcite apparently formed deeper within the sediments than the predominantly aragonitic crusts and slabs. Nodule formation was caused by anaerobic oxidation of methane dominantly involving archaea of the phylogenetic ANME-1 group, whereas aragonitic crusts resulted from the activity of archaea of the ANME-2 cluster. Evidence for this correlation is based on the distribution of specific biomarkers in the two types of carbonate aggregates, showing higher hydroxyarchaeol to archaeol ratios in the crusts as opposed to nodules. Formation of crusts closer to the seafloor than nodules is indicated by higher carbonate contents of crusts, probably reflecting higher porosities of the host sediment during carbonate formation. This finding is supported by lower d18O values of crusts, agreeing with precipitation from pore waters similar in composition to seawater. The aragonitic mineralogy of the crusts is also in accord with precipitation from sulfate-rich pore waters similar to seawater. Moreover, the interpretation regarding the relative depth of formation of crusts and nodules agrees with the commonly observed pattern that ANME-1 archaea tend to occur deeper in the sediment than members of the ANME-2 group. Methane represents the predominant carbon source of all carbonates (d13C values as low as -58.9 per mil V-PDB) and the encrusted archaeal biomarkers (d13C values as low as -140 per mil V-PDB). Oxygen isotope values of some nodular carbonates, ranging from + 3.9 to + 5.1per mil V-PDB, are too high for precipitation in equilibrium with seawater, probably reflecting the destabilization of gas hydrates, which are particularly abundant at the Kouilou pockmarks.

Sistemas de Gestión de la Calidad. Actividades del proceso de mejora continua: Estudio y Análisis de los defectos de construcción en edificación de viviendas

Uno de los pilares fundamentales que defienden el grupo de Normas ISO 9000 para garantizar la eficacia y eficiencia de los Sistemas de Gestión de la Calidad es la Mejora Continua. Para llevar a cabo el proceso de Mejora Continua es preciso empezar detectando y analizando donde estamos fallando y qué podemos mejorar. Organizaciones como PMI® asignan a esta actividad un proceso propio, que llaman también Lecciones Aprendidas y debe estar presente siempre, en todos los proyectos, ya que sólo conociendo nuestros fallos y analizando sus causas podemos tomar acciones preventivas que eviten que vuelvan a repetirse. Desafortunadamente, la experiencia práctica nos dice que, en la mayoría de los casos, esta actividad o no se ejecuta, o no se realiza de forma eficaz. La primera actividad que debería llevarse a cabo para detectar y analizar donde estamos fallando es la inspección del producto, en nuestro caso el edificio de viviendas, y realizar un listado de los defectos encontrados. Esta tarea, que debería realizarla la empresa constructora y ser supervisada por la Dirección de Ejecución de Obra, generalmente, no se realiza con el rigor suficiente que permita entregar al usuario su vivienda sin defectos aparentes. Se consideran repasos de postventa, dejando en el usuario final la responsabilidad de verificar el correcto acabado del producto que acaba de adquirir y que en la mayoría de los casos será la compra de mayor importe que realice en su vida. Cuando adquirimos cualquier objeto, un coche, un televisor, un teléfono móvil, etc., el fabricante es el responsable de verificar que el producto que está entregando al cliente o al suministrador no tiene daños o defectos aparentes. Sin embargo, cuando compramos una vivienda es el comprador o usuario final el que realiza, en la mayoría de los casos, esta verificación.

Comparación de cuatro sistemas de certificación del ámbito de la dirección de proyectos

En la comunicación se comparan cuatro sistemas de certificación en dirección de proyectos: IPMA, PMI, P2M y PRINCE2. Estos modelos tienen sus propios cuerpos de conocimiento y estándares, sus propios procesos de certificación y se aplican a nivel mundial. De estos modelos, IPMA y PMI son los que tienen un mayor reconocimiento internacional, PRINCE2 es reconocido principalmente en Europa, y P2M en Japón. Quince indicadores se han utilizado para comparar sus diferentes aspectos. Los resultados de la comparación nos han permitido conocer las similitudes y diferencias que existen entre los cuatro sistemas de certificación en dirección de proyectos. Las guías y estándares para la dirección de proyectos han sido desarrollados para diferentes propósitos: 1) brindar conocimiento y prácticas para la dirección de proyectos individuales (Proyectos), 2) brindar conocimiento y prácticas para la dirección de proyectos empresariales (Organizaciones), y 3) el desarrollo, evaluación y certificación de personas (Personas). De este modo, IPMA ha desarrollado sus guías y estándares para Proyectos y Personas; PMI para Proyectos, Organizaciones y Personas; PRINCE2 para Organizaciones; y P2M para Proyectos y Organizaciones.