GHB free acid: II. Isolation and spectroscopic characterization for forensic analysis

A reference standard for gamma-hydroxybutyric acid (GHB) free acid is not commercially available, making its analysis in forensic exhibits more difficult. GHB free acid is typically encountered in aqueous solution and in the presence of the lactone, gamma-butyrolactone (GBL), presenting difficulty in Fourier transform infrared (FT-IR) analysis. The strong infrared (IR) absorptivity of the GBL carbonyl band, the shifting of the GBL carbonyl band in aqueous solutions, and the position of the O-H bend for water can mask the main carbonyl band for GHB free acid. Model solutions of beta-hydroxybutyric acid (BHB) and GBL were studied in order to further understand the masking of the GHB free acid carbonyl band in FT-IR analysis. The use of second derivative FT-IR spectroscopy was shown to provide resolution of the free acid carbonyl band, and a presumptive test for GHB free acid was developed and applied. An extension of this work included preparing, for use as a standard reference material, small amounts (< or = 10 mg) of GHB free acid. Preparation was based on the instantaneous reaction of GHB's sodium salt with a stoichiometric amount of hydrochloric acid in aqueous solution, and subsequent isolation of the free acid in neat liquid form. Both FT-IR and proton nuclear magnetic resonance spectra of the neat reference material were obtained and used to verify its identity. The isolation of GHB free acid from actual forensic exhibits is also presented, with identity confirmation using FT-IR.     

毛发中GHB的检测及评价

目的探索毛发中外源性GHB的检测及判断的可行性,为涉GHB的鉴定提供方法和依据。方法建立毛发中GHB的GC/MS分析方法,并通过动物实验,考察毛发中内源性GHB的质量分数范围、外源性GHB在毛发中的时间过程以及给药剂量、毛发颜色与毛发中GHB的质量分数关系。结果豚鼠和中国人黑色毛发中内源性GHB质量分数分别为(3.01±1.41)ng/mg(n=28)和(1.02±0.27)ng/mg(n=20);摄GHB后毛发中GHB质量分数明显增加且与给药剂量呈正相关性;GHB在毛干中呈窄带分布;深色毛发中GHB质量分数高于浅色毛发。结论毛发中GHB的检测适用于GHB滥用和中毒的法医毒物学鉴定;根据毛发中的GHB质量分数和毛发分段分析可判断GHB的来源。     

A versatile technique for the investigation of gunshot residue patterns on fabrics and other surfaces: m-XRF

With heavy-metal-free ammunitions becoming more and more popular, it is necessary to find methods to visualize patterns of those elements in gunshot residues (GSRs) that are not accessible by chemographic coloring tests. The recently introduced millimeter-X-ray fluorescence analysis (m-XRF) spectrometer Spectro Midex M offers an easy way to record mappings of GSRs containing such elements in order to determine shooting distances as well as the general composition of these particles. A motorized stage enables samples of a maximum size of 20 x 20 cm to be investigated, like fabric, clothes, adhesive tapes (Filmolux films), and polyvinylalcohol gloves of shooter's hands. Human tissues can be measured using a Peltier-cooled specimen holder that is mounted onto the stage. As the spot size of the exiting X-rays lies in the millimeter range, which is adequate for the assessment of the residue patterns for shooting distance determination, a significant reduction in measurement time is achieved compared with mu-XRF methods. Test shots with heavy-metal-free ammunitions were performed on different target materials, like pork skin and fabric, and the elemental distributions of Ti, K, and Ga were determined. In order to show the capability of the spectrometer for conventional lead ammunitions as well, a shot series of 5-100 cm shooting distance and an adhesive tape of a shooter's hand were investigated analogously. A comparison of several methods applied in GSR investigation shows the advantages of the m-XRF method.     

习惯法/民间法研究范式的批判性理解——兼论社会控制概念在法学研究中的运用可能

概念是进行科学研究的基本分析工具,同时具有促进和制约研究的辩证属性,因此需要对概念进行反思。“习惯法”、“民间法”这两个概念对于挑战和批判“法律中心主义”具有重要学术贡献。但是“习惯法”、“民间法”概念定义过于宽泛,使其作为一种研究范式不能很好地对不同性质和不同运作方式的规范进行必要的区分,从而导致这种研究范式具有局限性。在法学研究中,可以尝试用“社会控制”概念来弥补习惯法/民间法研究范式的不足。     

A CONSUMER-WELFARE APPROACH TO NETWORK NEUTRALITY REGULATION OF THE INTERNET

"Network neutrality" is the shorthand for a proposed regimeof economic regulation for the Internet. Because of the trendto deliver traditional telecommunications services, as wellas new forms of content and applications, by Internet protocol(IP), a regime of network neutrality regulation would displaceor subordinate a substantial portion of existing telecommunicationsregulation. If the United States adopts network neutrality regulation,other industrialized nations probably will soon follow. As aresult of their investment to create next-generation broadbandnetworks, network operators have the ability to innovate insidethe network by offering both senders and receivers of informationgreater bandwidth and prioritization of delivery. Network neutralityregulation would, among other things, prevent providers of broadbandInternet access service (such as digital subscriber line (DSL)or cable modem service) from offering a guaranteed, expediteddelivery speed in return for the payment of a fee. The practicaleffect of banning such differential pricing (called "accesstiering" by its critics) would be to prevent the pricing ofaccess to content or applications providers according to priorityof delivery. To the extent that an advertiser of a good or servicewould be willing to contract with a network operator for advertisingspace on the network operator's affiliated content, anotherpractical effect of network neutrality regulation would be toerect a barrier to vertical integration of network operatorsinto advertising-based business models that could supplementor replace revenues earned from their existing usage-based businessmodels. Moreover, by making end-users pay for the full costof broadband access, network neutrality regulation would denybroadband access to the large number of consumers who wouldnot be able to afford, or who would not have a willingness topay for, what would otherwise be less expensive access. Forexample, Google is planning to offer broadband access to end-usersfor free in San Francisco by charging other content providersfor advertising. This product offering is evidently predicatedon the belief that many end-users demand discounted or freebroadband access that is paid for by parties other than themselves.Proponents of network neutrality regulation argue that suchrestrictions on the pricing policies of network operators arenecessary to preserve innovation on the edges of the network,as opposed to innovation within the network. However, recognizingthat network congestion and real-time applications demand somedifferential pricing according to bandwidth or priority, proponentsof network neutrality regulation would allow broadband Internetaccess providers to charge higher prices to end-users (but notcontent or applications providers) who consume more bandwidthor who seek priority delivery of certain traffic. Thus, thedebate over network neutrality is essentially a debate overhow best to finance the construction and maintenance of a broadbandnetwork in a two-sided market in which senders and receivershave additive demand for the delivery of a given piece of information—andhence additive willingness to pay. Well-established tools ofRamsey pricing from regulatory economics can shed light on whethernetwork congestion and recovery of sunk investment in infrastructureare best addressed by charging providers of content and applications,broadband users, or both for expedited delivery. Apart fromthis pricing problem, an analytically simpler component of proposednetwork neutrality regulation would prohibit a network operatorfrom denying its users access to certain websites and Internetapplications, such as voice over Internet protocol (VoIP). Althoughsome instances of blocking of VoIP have been reported, suchconduct is not a serious risk to competition. To address thisconcern, I analyze whether market forces (that is, competitionamong access providers) and existing regulatory structures aresufficient to protect broadband users. I conclude that economicwelfare would be maximized by allowing access providers to differentiateservices vis-à-vis providers of content and applicationsin value-enhancing ways and by relying on existing legal regimesto protect consumers against the exercise of market power, shouldit exist.