Immunologic sperm detection]

Proof of prostatic acid phosphatase with the enzyme-immuno-assay (EIA) is specific and as sensitive as the common phosphatase reaction. The EIA for prostatic-specific-antigen (PSA) is prostate specific as well, but less sensitive than the phosphatase assay. In a review of 30 own cases no indications for nonspecifity of the immuno assay were obtained. A positive EIA-test in absence of spermatozoa can be explained by either azoospermia or a prolonged persistence of prostatic acid phosphatase in comparison with spermatozoa.     

The risk of detection

The clearance rate is often used as an indicator of the risk of detection, in spite of the fact that these are different matters. This article suggests a method to make estimates of the risk of detection based on information from the Swedish crime statistics. The risk of detection is expressed as a function of the dark figure. Empirical estimates of the risk are given for drunken driving, residential burglary, and assault between strangers. These estimates are followed up with some calculations concerning the impact of crime activity level on the risk of getting caught. One major conclusion of the findings is that the risk of detection varies very moderately with the dark figure. This means that if there is some knowledge of the dark figure, it is often possible to make fairly good estimates of the risk of detection.     

Fingermarks detection by eosin-blue dye

Eosin-blue (I) dye, along with a phase transfer catalyst, has been used to detect latent fingerprints on a wide range of surfaces, including paper, glass, steel, lamination sheets, polythene, plastic and bakelite.     

GC双检测器技术筛选常见毒(药)物的可行性研究

利用气相色谱仪 ,在样品进样经单柱分离后通过Y形管连接至两个不同选择性检测器 (NPD/FID)的方法 ,考察气相色谱操作条件对双检测器响应比值的影响及其该法用于复杂样品测定的可行性。结果表明当实验条件保持不变时 ,NPD/FID响应比值具有较好的重现性。改变检测器操作参数和色谱条件对NPD/FID响应比值都有影响 ,但相对于某一参比物计算得到的相对NPD/FID响应比值受影响很小。样品中待测组份的浓度改变不影响NPD/FID响应比值。在有标准品比对的情况下 ,NPD/FID响应比值或相对NPD/FID响应比值可以作为定性分析的一个参数。     

The detection of simulated amnesia

Claims of amnesia are frequently raised in criminal and civil cases. There is a consensus in the legal community that amnesia is easily faked and practically impossible to disprove, and that many who claim to be amnesic are malingering. The present studies compared, on a variety of memory tasks, subjects instructed to simulate amnesia with subjects who had memory impairments due to brain damage. The simulators displayed patterns of performance different from those of memory-impaired subjects. These results suggest that lay-people have inaccurate beliefs about the cognitive features of amnesia, and do not distinguish among etiologically distinct amnestic disorders. Tasks that exploit lay-people's inaccurate beliefs about amnesia appear promising for the detection of malingering.     

Histologic detection of fat emboli

We describe a procedure for detection of fat emboli in formalin fixed tissue using osmium tetroxide postfixation. Intravascular fat in tissue postfixed in osmium tetroxide, embedded in epoxy or paraffin, and stained with toluidine blue, hematoxylin, or Oil Red O is more easily visualized than in frozen tissue that is stained with Oil Red O. With these methods, fat emboli may be detected years after the initial autopsy.     

Postmortem detection of hemp intoxication

The diagnostic tools applicable to the forensic medical expertise of cadavers in cannabinoid intoxication (CI) were evaluated. Histochemistry with incubation of stable blue "B" (SBB) were used for the detection of cannabinoids in the bronchi and lungs. Hyperemia and capillarostasis in the mucous tunics of the mouth and stomach as well as hyperemia and edema in the lungs and brain were histochemically detected in CI. The histochemical activity of aldehyde dehydrogenase (AlDG) was most essentially decreasing in the adrenal glands and brain of younger persons. The SBB reaction in the bronchial and alveolar epithelia was positive in 85% of cases. A high proof value of the CI diagnostics was pointed out in cadaver expertise.     

Forensic chemical detection of furadan

Isolation of furadan from biological material by ethyl acetate is considered. Column chromatography with silicone gel L 100/160micro was used to purify extractions from biological objects. A technique was elaborated for identification and quantitation of furadan in cadavers. It is possible to use this technique in forensic expert examination.     

JPEG steganography detection with Benford's Law

In this paper we present a novel approach to the problem of steganography detection in JPEG images by applying a statistical attack. The method is based on the empirical Benford's Law and, more specifically, on its generalized form. We prove and extend the validity of the logarithmic rule in colour images and introduce a blind steganographic method which can flag a file as a suspicious stego-carrier. The proposed method achieves very high accuracy and speed and is based on the distributions of the first digits of the quantized Discrete Cosine Transform coefficients present in JPEGs. In order to validate and evaluate our algorithm, we developed steganographic tools which are able to analyse image files and we subsequently applied them on the popular Uncompressed Colour Image Database. Furthermore, we demonstrate that not only can our method detect steganography but, if certain criteria are met, it can also reveal which steganographic algorithm was used to embed data in a JPEG file.     

Postmortem detection of isopropanol in ketoacidosis

Isopropanol (IPA) detected in deaths because of diabetic ketoacidosis (DKA) or alcoholic ketoacidosis (AKA) may cause concern for IPA poisoning. This study addressed this concern in a 15-year retrospective review of 260 deaths in which concentrations of acetone and IPA, as well as their ratios, were compared in DKA (175 cases), AKA (79 cases), and IPA intoxication (six cases). The results demonstrated the frequency of detecting IPA in ketoacidosis when there was no evidence of IPA ingestion. IPA was detectable in 77% of DKA cases with quantifiable concentrations averaging 15.1 ± 13.0 mg/dL; 52% of AKA cases with quantifiable concentrations averaging 18.5 ± 22.1 mg/dL; and in cases of IPA intoxication, averaging 326 ± 260 mg/dL. There was weak correlation of IPA production with postmortem interval in DKA only (r = -0.48). Although IPA concentrations were much higher with ingestion, potentially toxic concentrations were achievable in DKA without known ingestion.     

Crime scene staging and its detection

Crime scene staging is a recognized phenomenon within the criminal justice field. This article defines the occurrence for staging, identifies the motives for staging, and identifies the act that precipitated the staging. It reports the results of an exploratory survey of 20 well-versed and highly trained law enforcement officers' experience with staging in fatal and nonfatal incidents, and it reports the most commonly observed forms of crime scene staging. Investigative strategies and indicators of staging are also presented.     

Photoluminescent semiconductor nanocrystals for fingerprint detection

The concept of utilizing photoluminescent semiconductor nanocrystals for latent fingerprint detection, especially in concert with phase-resolved imaging for background fluorescence suppression, is reduced to practice with CdS nanocrystals that are capped with dioctyl sulfosuccinate. The nanocrystals are dissolved in heptane or hexane and are applied in much the same way as staining with fluorescent dye, on articles that have been pre-fumed with cyanoacrylate ester and also on the sticky side of electrical tape without pre-fuming. Since CdS can form a photoluminescent nanocomposite with dendrimers, a feasibility examination of dendrimer tagging of fingerprints has also been conducted.     

Voice stress evaluators and lie detection

Proponents of vocal stress analysis systems argue that they are able to detect spoken deception by analysis of "stress" in the voice signal. Presumably, they do so by examining traces made by laryngeal microtremors which, they claim exist in the voice, are associated with stress, and ultimately are associated with lying. However, most research that seeks to identify the relationships between microtremors and laryngeal function has produced negative results, and data on the ability of voice analyzers to detect stress from speech--or to identify spoken deception--have been negative or "mixed" in nature. Since perspectives based on available results leave a number of questions unanswered, a series of experiments has been undertaken. The first was focused on the basic acoustic/temporal correlates of stress in voice (the subject of an earlier report), the second on examination of stress by commercial voice analyzers, and the third on the detection of relatively high-risk lies by this same type of voice analysis procedure. It was found that correct stress/nonstress identifications occurred only at chance levels; the lie/nonlie identification scores were quite similar with professional "examiners" performing at about the same level of accuracy as other auditors. The following review is divided into two parts: a history of the controversy and a presentation of the two cited experiments.