The Effect of Temperature and Exposure Time on Stability of Cholesterol and Squalene in Latent Fingermarks Deposited on PVDF Membrane

Cholesterol and squalene are fatty materials of latent fingermarks that can be utilized for dating methodologies and visualization techniques. Previous studies have suggested these compounds undergo degradation in fingermarks as a function of time (days) and light at ambient temperature. However, studies assessing how their composition changes at low and high temperatures over short periods of time (hours) have not been published previously. Here, we performed quantitative analysis of cholesterol and squalene in natural fingermark residue using PVDF membrane, after exposure to a range of temperatures (−20 to 100°C) for 4 and 8 h. We found that levels of both fatty materials remained constant at −20 to 60°C, but both showed significant reduction at 100°C, over short exposure times. These results indicate that cholesterol and squalene are detectable at −20 to 60°C, whereas at 100°C or higher, both are lost due to rapid thermal degradation.     

放火罪的处罚根据

放火罪的保护法益是公共安全。行为人烧毁自己财物本身并不违法,行为人烧毁自己财物构成放火罪的处罚根据在于这种行为危及公共安全,因此,公共安全应当解释为是一种构成要件要素。即便放火后达到独立燃烧的程度,还不能说发生了财产侵害,因此,通说有过于强调危及公共安全而忽视放火罪所具有的毁弃、损坏罪的一面。独立燃烧说将会导致放火罪的既遂时点提前而几乎没有成立未遂犯和中止犯的余地的后果。     

A Noninvasive and Speculative Method of Visualizing Latent Fingerprint Deposits on Thermal Paper

Latent fingerprint deposits on thermal paper have been visualized noninvasively at visible wavelengths when illuminated with a UV‐A light source (peak 365 nm). A higher intensity UV source (250 W/m² at 0.38 m) gave superior fingerprint visibility when compared with a 60 W/m² (at 0.4 m) source. Removing the visible (blue) component of the light source emission did not adversely affect the visibility of the fingerprint. Sample fingerprints from 100 donors, when examined 24 h after deposition, produced identifiable fingerprints from nearly 34% of fingerprint deposits. A mechanism for the observed visibility is proposed based on low emission of visible wavelengths from areas of thermal paper coincident with the fingerprint deposit, when illuminated with UV. This is likely due to a weak color change in the thermal paper dye arising from protonated amino acid components of the sweat. This effect was not observed on nonthermal paper.     

Response Assessment of Thermal Papers from Four Continents to Fingerprint Development by Heat

Latent fingerprint deposits on thermal paper sourced from the U.S., China, the U.K., and Australia have been visualized by heating. U.S. and Chinese sourced paper produced two distinct types of fingerprint development. In one type (type 1), the paper dye colors where the deposit is present (as previously reported) and in the other type (type 2) the ‘inverse’ of this gives paper coloring only in areas not coincident with the deposit. Both development types gave identifiable fingerprints, the majority fading within 24 h of heating. Fingerprint development from U.K. and Australian sourced paper was exclusively type 1 and resistant to fading. Temperatures for fingerprint visualization were higher for U.S. paper (64–71°C) and Chinese paper (75–95°C) than for U.K. and Australian sourced paper (43–50°C). Particularly for Chinese sourced paper, these temperatures were within a few degrees of the normal paper color temperature. A mechanism for type 2 fingerprint development is proposed.     

A simple microthermal desorption device

A new method for thermal desorption of small samples is presented. The method uses a solid phase microextraction (SPME) holder with the fiber removed. The sample-for example, an ink sample on paper-is simply placed inside the needle of the holder, where normally an SPME fiber is positioned. The thermal desorption is then performed on any kind of gas chromatograph in a manner similar to that for SPME analysis. The needle of the SPME holder penetrates the injector septum; the temperature of the thermal desorption is simply the temperature of the injector. No solvents or liquid nitrogen cooling are used. The paper sample is kept inside the holder needle during the analysis. After the analysis is completed, the sample is removed from the needle by pushing forward the steel wire inside the needle in the way normally used to perform sampling with the SPME fiber. The desorbed compounds were analyzed by gas chromatography with a flame ionization detector or by gas chromatography-mass spectrometry. The optimum temperature for desorption of ink samples on paper was 200 degrees C. The influence of the paper matrix is negligible at that temperature. Laboratories lacking the commercial device for thermal desorption can use this cheap device for the analysis of, for example, writing ink, printing ink, and inkjet ink samples on paper. Other types of samples can be investigated but the size of samples suitable for analysis is limited.     

Use of thermal drone in detection and assessment of larval mass temperature in decomposed rabbit carcasses

Manual ground searches and cadaver dogs are traditional methods for locating remains, but they can be time- and resource-intensive, resulting in the decomposition of bodies and delay in victim identification. Therefore, thermal imaging has been proposed as a potentially useful tool for detecting remains based on their temperature. This study investigated the potential of a novel search technique of thermal drones to detect surface remains through the detection of maggot mass temperatures. Two trials were carried out at Selangor, Malaysia, each utilizing 12 healthy male Oryctolagus cuniculus European white rabbits and DJI Matrice 300 RTK drone China, equipped with a thermal camera; Zenmuse H20T to record the thermal imaging footage of the carcasses at various heights (15, 30, 60–100 m) for 14 days for each trial. Our results demonstrated that the larval masses and corresponding heat emissions were at their largest during the active decay stage; therefore, all the carcasses were observable in thermal images on day 5 and remained until day 7. Statistical analyses showed that (1) no statistically significant differences in thermal images between clothed and unclothed subjects (p > 0.05); (2) 15 m above ground level was proven to be the optimal height, as it showed the greatest contrast between the carcass heat signature and the background (p < 0.005). Our data suggested the potential window of detection of thermal signatures was detectable up to 7 days post-deposition. This could be an important guideline for the search and recovery teams for operational implementation in this tropical region.     

Refreshing the Aged Latent Fingerprints with Ionizing Radiation Prior to the Cyanoacrylate Fuming Procedure: A Preliminary Study

One of the crucial factors determining the cyanoacrylate deposit quality over latent fingerprints appeared to be the extent of the humidity. This work focuses on the enhancement/refreshment of age‐degraded latent fingerprints by irradiating the samples with UV, X‐ray, or thermal neutrons prior to the cyanoacrylate (CA) fuming. Age degradation of latent fingerprints deposited on glass surfaces was examined through the decrease in the number of characteristic minutiae counts over time. A term “critical day” was introduced for the time at which the average number of identifiable minutiae definitions drops to one‐half. Fingerprints older than their “critical day” were exposed to either UV, X‐ray, or thermal neutrons. Identical reference samples were kept unexposed. All samples, both reference and irradiated, were developed during a single CA fuming procedure. Comparative latent fingerprint analysis showed that exposure to ionizing radiation enhances the CA fuming, yielding a 20‐30% increase in average minutiae count.     

Cardiac Ventricular Laceration Due to Child Abuse: Abusive Ventricular Laceration

Traumatic cardiac ventricular ruptures in children are rare. Only a single case of left ventricular rupture due to child abuse has been reported. We report a child who sustained a fatal left ventricular apical rupture. It appeared to have resulted from hydrostatic forces resulting from abusive blunt thoracic injury. That he was being abused was previously missed when he was presented to the emergency department with facial pyoderma. It was not noted that he also had lip and oral mucosal injury, sites not affected by staph toxins. As a result, his underlying, abusive and secondarily infected, facial flow type scald burn was not appreciated. Within a week thereafter his fatal injury occurred, accompanied by extensive and obvious associated abusive injuries. Postmortem high‐detail whole body computed tomography scanning aided the autopsy. Although rare, ventricular rupture from abusive blunt thoracic injury can occur.     

差示扫描量热法检验合成纤维

目的研究不同种类合成纤维以及不同厂家生产的同种类合成纤维的鉴别方法。方法应用功率补偿型差示扫描量热仪测定涤纶、腈纶、锦纶、丙纶、氨纶、氯纶等6种常见合成纤维和10个厂家生产的涤纶纤维的DSC曲线,并对热学参数进行计算和分析。结果涤纶、腈纶、锦纶、丙纶、氨纶、氯纶的DSC曲线明显不同,10个厂家生产的涤纶纤维的DSC曲线虽然非常相近,但对其熔融温度Tm、熔融峰顶温度Tmp、熔融焓变ΔHm、结晶温度Tc、结晶峰顶温度Tcp和结晶焓变ΔHc等热学参数的计算结果显示,10个涤纶纤维的参数并不完全相同。结论差示扫描量热法不但能对不同种类的合成纤维进行鉴别,也可区分不同厂家生产的同种类纤维,从而为案件侦破提供更为准确的方向、线索和证据。     

皮肤烧伤愈合过程中磷酸化c-Jun的表达

目的观察烧伤后人皮肤磷酸化c-Jun(p-c-Jun)的变化特点,初步探讨烧伤后创面愈合的分子机制。方法取12例烧伤后住院植皮患者的烧伤周边区皮肤为实验组;另取正常皮肤12例为对照组。应用免疫组织化学方法和常规HE染色检测p-c-Jun在皮肤烧伤周边区和正常皮肤组织中的变化情况。结果对照组p-c-Jun阳性颗粒主要定位于表皮细胞和内皮细胞中,阳性细胞率为(13.9±2.7)%;实验组p-c-Jun阳性颗粒主要定位于表皮细胞和部分炎细胞中,阳性细胞率上升至(47.2±8.6)%,明显高于对照组(P0.01)。结论烧伤后人皮肤p-c-Jun的表达可能与创面愈合有关。