Utilized coefficient of friction during walking: static estimates exceed measured values

This study compared utilized coefficient of friction (COF) measured during nonslip pedestrian gait to estimated utilized COF values calculated using anthropometric (i.e., leg length) and stride characteristic data (i.e., impact angle, step length). Twenty healthy adults walked at slow, medium, and fast speeds with kinematic and kinetic data recorded simultaneously. Estimated and measured impact angle varied with walking speed, with greater angles evident with faster speeds (p < 0.001 and p < 0.05, respectively). The estimated impact angle was greater than the measured impact angle (p < 0.05). Estimated and measured peak utilized COF values varied with walking speed, with higher utilized COF values evident with faster speeds (p < 0.001 and p = 0.001, respectively). Estimated utilized COF values were 86, 118, and 131% greater than measured peak utilized COF values for slow, medium, and fast speeds, respectively (p < 0.001). Higher estimated utilized COF values varied moderately with increased measured peak utilized COF values (r = 0.522; p < 0.001). These data suggest that impact angle and step length alone cannot be used to accurately assess the utilized COF on level walking surfaces.     

Genetic data for the 13 CODIS STR loci in Singapore Chinese

Allele frequencies for the 13 CODIS STR loci included in the AmpFISTR Profiler Plus and AmpFISTR Cofiler kits (Applied Biosystems, Foster City, USA) were determined in a sample of 209 unrelated Chinese in Singapore. The combined random match probability for the 13 loci is about 6.6 x10(-15) and the overall probability of excluding paternity is 0.9999899. The results demonstrate that the loci are useful for forensic human identification and parentage testing for the Chinese population in Singapore.     

Preparation and application of a fortified hair reference material for the determination of methamphetamine and amphetamine

Quality assurance is one of the major issues in forensic analytical laboratories, where the need for a reference material (RM) has rapidly increased. RMs are very useful for method development and validation, internal quality control or proficiency tests. In the present study, we prepared a RM using drug-free hair for the determination of methamphetamine (MA) and its main metabolite, amphetamine (AP) according to the recommendations of ISO Guide 35. The concentrations of MA and AP were determined using two extraction methods, agitation with 1% HCl in methanol at 38 degrees C and ultrasonication with methanol/5M HCl (20:1), followed by gas chromatography/mass spectrometry (GC/MS) after derivatization with trifluoroacetic anhydride (TFAA). The assignment of values was conducted through the homogeneity study and characterization of the material. Furthermore, an internal proficiency test was performed with the prepared RM, of which the results were compared with those of the authentic hair RM prepared in our previous study. As a result, a hair RM containing MA and AP was prepared at the level of 4.86+/-0.69 ng/mg and 4.63+/-0.44 ng/mg, respectively. Most participants showed satisfactory performances in the internal proficiency test with the both RMs. The hair RM prepared in this study demonstrated its suitability for quality assurance in forensic laboratories.     

Study of the Behaviors of Gunshot Residues from Spent Cartridges by Headspace Solid‐Phase Microextraction–Gas Chromatographic Techniques

Gunshot residues, produced after shooting activity, have acquired their importance in analysis due to the notoriety of firearms‐related crimes. In this study, solid‐phase microextraction was performed to extract the headspace composition of spent cartridges using 85‐μm polyacrylate fiber at 66°C for 21 min. Organic compounds, that is, naphthalene, 2,6‐dinitrotoluene, 2,4‐dinitrotoluene, diphenylamine, and dibutyl phthalate were detected and analyzed by gas chromatography‐flame ionization detection technique. Evaluation of chromatograms for diphenylamine, dibutyl phthalate, and naphthalene indicates the period after a gunshot was discharged, whether it was 1 days, 2–4 days, <5 days, 10 days, 20 days, or more than 30 days ago. This study revealed the potential effects of environmental factors such as occasional wind blow and direct sunlight on the estimation of time after spent cartridges were discharged. In conclusion, we proposed reliable alternative in analyzing the headspace composition of spent cartridges in a simulated crime scene.     

Comparison of Four Saliva Detection Methods to Identify Expectorated Blood Spatter

Blood spatter analysis is an important step for crime scene reconstruction. The presence of saliva in blood spatter could indicate expectorated blood which is difficult to distinguish from impact spatter. In this study, four saliva test methods (SALIgAE^®, Phadebas^® sheet, RSID^™-Saliva kit, and starch gel diffusion) were compared to identify the best method for detecting expectorated blood spatter. The RSID^™-Saliva kit showed the highest sensitivity even when saliva was mixed with blood, and was not inhibited by the presence of blood. The SALIgAE^® test provided easy and rapid results, but the yellow color of a positive reaction was overwhelmed by the red color of the blood. The starch gel diffusion method and the Phadebas^® sheet exhibited relatively low sensitivity and the assay took a long time. When using the RSID^™-Saliva kit for identifying saliva in blood, results should be read within 10 min.     

The Longest March: Why China’s Democratization is Not Imminent

Journal of Chinese Political Science - Will China democratize? If so, how soon? Relying on classical modernization theory and observations of China’s extraordinary economic growth, many...     

The “Nanny”, the “Fighter,” and the “Puppet”: a Brief Political Biographical History of Carrie Lam Cheng Yuet-ngor Including the Earliest Days of Her Chief Executive Appointment

Carrie Lam Cheng Yuet-ngor has broken many ceilings as Hong Kong’s first female Chief Executive and the first post-Occupy Central leader. The mission of the political biographer is to contextualize Lam’s policies in the circumstances that she was put into and/or inherited from previous administrations without any value judgments (or highly minimized ones). The purpose is to recognize Lam as a complex entity characterized by a triad of images that include caring a senior civil servant, a tough-talking iron lady (nicknamed “The Fighter”) and a compliant Beijing loyalist (nicknamed “The Puppet” or “CY Leung 2.0”). The readers are the ultimate arbiters and evaluators of these narratives and perceptions to craft their own impression of Lam. The writing is organized into sections analyzing Lam’s family background, her rise in the civil service, her appointment as Chief Secretary, and her current tenure as the Chief Executive. The significance of this writing is an early assessment of Lam’s achievements and policy direction and a recount of her initiatives when she was Chief Secretary that can later be compared to post-administration retirement biographical writings for a full understanding of her political achievements and failures. Taken together, these accounts can then be a combined diachronic and synchronic historical biographical accounts of Lam.