Analytical separations of mammalian decomposition products for forensic science: A review

The study of mammalian soft tissue decomposition is an emerging area in forensic science, with a major focus of the research being the use of various chemical and biological methods to study the fate of human remains in the environment. Decomposition of mammalian soft tissue is a postmortem process that, depending on environmental conditions and physiological factors, will proceed until complete disintegration of the tissue. The major stages of decomposition involve complex reactions which result in the chemical breakdown of the body's main constituents; lipids, proteins, and carbohydrates. The first step to understanding this chemistry is identifying the compounds present in decomposition fluids and determining when they are produced. This paper provides an overview of decomposition chemistry andreviews recent advances in this area utilising analytical separation science

Observations of the temporal variation in chemical content of decomposition fluid: A preliminary study using pigs as a model system

In this paper we report the results of our preliminary studies into short chain fatty acids that have the potential to show reproducible patterns over certain postmortem intervals during decomposition in the absence of a soil matrix. Additional compounds that were detected, including several long chain fatty acids, were also investigated for their potential in estimating postmortem interval. Analysis of data was conducted to establish any distinct relationship between the levels of particular compounds produced with respect to time and temperature. Pork rashers (belly pork), whole stillborn piglets and whole adult pig (Sus scrofa) carcasses were used to model the human decomposition process in two separate locations, Western Australia (Perth) and Southern Canada (Oshawa). Thisenabled a comparison of components to be carried out under significantly different climatic conditions. Compounds were identified after analysis with gas-chromatography mass-spectrometry. Preliminary observations indicate that both short-chain and long-chain acids followed an apparent cyclic trend. All trials showed differences with respect to rate of decomposition, both between trials and between subjects in the same trial; however, the identity of the compounds detected for the pork rasher trial (Perth) and the pig trial (Canada) remained very similar

Origin of the transient unpulsed radio emission from the PSR B1259-63 binary system

We discuss the interpretation of transient, unpulsed radio emission detected from the unique pulsar/Be-star binary system PSR B1259-63. Extensive monitoring of the 1994 and 1997 periastron passages has shown that the source flares over a 100-day interval around periastron, varying on time-scales as short as a day and peaking at 60 mJy (~100 times the apastron flux density) at 1.4 GHz. Interpreting the emission as synchrotron radiation, we show that (i) the observed variations in flux density are too large to be caused by the shock interaction between the pulsar wind and an isotropic, radiatively driven, Be-star wind, and (ii) the radio emitting electrons do not originate from the pulsar wind. We argue instead that the radio electrons originate from the circumstellar disk of the Be star and are accelerated at two epochs, one before and one after periastron, when the pulsar passes through the disk. A simple model incorporating two epochs of impulsive acceleration followed by synchrotron cooling reproduces the essential features of the radio light curve and spectrum and is consistent with the system geometry inferred from pulsed radio data.Comment: To be published in Astrophysical Journal Letters 7 pages, 1 postscript figur

Further investigations into the single metal deposition (SMD II) technique for the detection of latent fingermarks

Single metal deposition (SMD II), a recently proposed method for the development of latent fingermarks, was investigated by systematically altering aspects of the procedure to assess their effect on the level of development and contrast achieved. Gold nanoparticle size, temperature of the deposition solution bath, and orbital shaking during detection were shown to affect the levels of development and contrast obtained. Gold nanoparticles of diameter 15–21 nm were found to be most effective for satisfactory visualisation of latent fingermarks, while solutions that were applied at room temperature were found to adequately balance the ratio between the contrast of the fingermark ridge detail and the level of background staining achieved. Finally, optimum levels of development and contrast were obtained through constant agitation of both solution baths at approximately 50 RPM throughout the submersion time. SMD II was also tested on a large variety of substrate types and shown to be effective on a range of porous, non-porous, and semi-porous surfaces; however, the detection quality can be significantly influenced by the substrate nature. This resulted in the production of dark grey, white, or gold coloured fingermarks on different surfaces, as well as reversed detection on certain types of plastic, similarly seen through the use of vacuum metal deposition. © 2016 Elsevier Ireland Lt

A systematic review of factors associated with outcome of psychological treatments for post-traumatic stress disorder

Objective: Psychological interventions for post-traumatic stress disorder (PTSD) are not always effective and can leave some individuals with enduring symptoms. Little is known about factors that are associated with better or worse treatment outcome. Our objective was to address this gap. Method: We undertook a systematic review following Cochrane Collaboration Guidelines. We included 126 randomized controlled trials (RCTs) of psychological interventions for PTSD and examined factors that were associated with treatment outcome, in terms of severity of PTSD symptoms post-treatment, and recovery or remission. Results: Associations were neither consistent nor strong. Two factors were associated with smaller reductions in severity of PTSD symptoms post-treatment: comorbid diagnosis of depression, and higher PTSD symptom severity at baseline assessment. Higher education, adherence to homework and experience of a more recent trauma were associated with better treatment outcome. Conclusion: Identifying and understanding why certain factors are associated with treatment outcome is vital to determine which individuals are most likely to benefit from particular treatments and to develop more effective treatments in the future. There is an urgent need for consistent and standardized reporting of factors associated with treatment outcome in all clinical trials

Biocatalytic dearomatisation of para-fluorobenzoic acid:Access to versatile homochiral building blocks with quaternary centres

The enzyme benzoate dioxygenase (BZDO) from Ralstonia eutropha B9 is able to dihydroxylate benzoic acids in a dearomative process that proceeds with a different regioselectivity than other known dioxygenase enzymes. Here we show that 4-fluorobenzoic acid is oxidised by BZDO to give an enantiopure diol that can be rapidly elaborated to highly oxygenated homochiral building blocks with quaternary centres. Notably, the diol produced in this biotransformation displays reactivity which is distinct from that of the more extensively studied non-fluorinated analogue

Metabolic Comparison of One-Anastomosis Gastric Bypass, Single-Anastomosis Duodenal-Switch, Roux-en-Y Gastric Bypass, and Vertical Sleeve Gastrectomy in Rat

Background One-anastomosis gastric bypass (OAGB) and single-anastomosis duodenal switch (SADS) have become increasingly popular weight loss strategies. However, data directly comparing the effectiveness of these procedures with Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (SG) are limited. Objectives To examine the metabolic outcomes of OAGB, SADS, RYGB, and SG in a controlled rodent model. Setting Academic research laboratory, United States. Methods Surgeries were performed in diet-induced obese Long-Evans rats, and metabolic outcomes were monitored before and for 15 weeks after surgery. Results All bariatric procedures induced weight loss compared with sham that lasted throughout the course of the study. The highest percent fat loss occurred after OAGB and RYGB. All bariatric procedures had improved glucose dynamics associated with an increase in insulin (notably OAGB and SADS) and/or glucagon-like protein-1 secretion. Circulating cholesterol was reduced in OAGB, SG, and RYGB. OAGB and SG additionally decreased circulating triglycerides. Liver triglycerides were most profoundly reduced after OAGB and RYGB. Circulating iron levels were decreased in all surgical groups, associated with a decreased hematocrit value and increased reticulocyte count. The fecal microbiome communities of OAGB, SADS, and RYGB were significantly altered; however, SG exhibited no change in microbiome diversity or composition. Conclusions These data support the use of the rat for modeling bariatric surgical procedures and highlight the ability of the OAGB to meet or exceed the metabolic improvements of RYGB. These data point to the likelihood that each surgery accomplishes metabolic improvements through both overlapping and distinct mechanisms and warrants further research

Assessing a novel contact heater as a new method of recovering explosives traces from porous surfaces

It can be very challenging to recover explosives traces from porous surfaces, such as clothing and car seats, compared to non-porous surfaces. The contact heater has been developed as a novel instrument designed to recover explosives traces from porous surfaces. Samples are taken by heating and drawing air across a surface, with the air flowing through a sampling cartridge containing adsorbent polymer beads, which act to trap any recovered explosive material. Any collected explosive can then be eluted from this cartridge using a solvent, prior to analysis. This paper outlines work performed to evaluate the usefulness of the contact heater with regards to the recovery of explosives traces from porous materials. Ethylene glycol dinitrate (EGDN) and triacetone triperoxide (TATP) were chosen as two representative explosives for this study. Quantification was performed using GC–MS for EGDN and LC–MS/MS for TATP. Different sampling temperatures, sampling times and elution solvents were investigated. Recovery was trialled from leather, carpet and denim. Recoveries of up to 71% were obtained following optimisation. It was also possible to recover TATP from fabrics exposed to TATP vapour in a vapour-laden jar up to two hours after exposure. The contact heater therefore appears to be a very useful tool for the recovery of explosives traces from porous materials

Fingermark simulants and their inherent problems: A comparison with latent fingermark deposits

Commercially available fingermark simulants werecompared to latent fingermark deposits to assess their efficacy asstandards for a quality control assessment of fingermark developmentreagents. Deposits of the simulants and latent fingermarks were madeon paper substrates and were developed using reagents that targetamino acids (ninhydrin, 1,2-indanedione) and sebaceous secretions(Oil Red O, physical developer). The resulting marks were comparedfor visibility and color. Significant differences were observed betweenthe simulants and latent fingermarks in response to the fingermarkdevelopment reagents. Infrared spectroscopic analysis of the simulantscompared to untreated latent fingermarks revealed differencesin chemical composition. These results indicate that these simulantsare not well suited as quality control standards in forensic laboratoriesand should be used with extreme caution in any form of research intolatent fingermark detection

Metabolomic-based biomarker discovery for non-invasive lung cancer screening:A case study

BACKGROUND: Lung cancer (LC) is one of the leading lethal cancers worldwide, with an estimated 18.4% of all cancer deaths being attributed to the disease. Despite developments in cancer diagnosis and treatment over the previous thirty years, LC has seen little to no improvement in the overall five year survival rate after initial diagnosis. METHODS: In this paper, we extended a recent study which profiled the metabolites in sputum from patients with lung cancer and age-matched volunteers smoking controls using flow infusion electrospray ion mass spectrometry. We selected key metabolites for distinguishing between different classes of lung cancer, and employed artificial neural networks and leave-one-out cross-validation to evaluate the predictive power of the identified biomarkers. RESULTS: The neural network model showed excellent performance in classification between lung cancer and control groups with the area under the receiver operating characteristic curve of 0.99. The sensitivity and specificity of for detecting cancer from controls were 96% and 94% respectively. Furthermore, we have identified six putative metabolites that were able to discriminate between sputum samples derived from patients suffering small cell lung cancer (SCLC) and non-small cell lung cancer. These metabolites achieved excellent cross validation performance with a sensitivity of 80% and specificity of 100% for predicting SCLC. CONCLUSIONS: These results indicate that sputum metabolic profiling may have potential for screening of lung cancer and lung cancer recurrence, and may greatly improve effectiveness of clinical intervention