Gas chromatography was used to study the cannabinoid content ("potency") of illicit cannabis seized by police in England in 2004/5. Of the four hundred and fifty two samples, indoor-grown unpollinated female cannabis ("sinsemilla") was the most frequent form, followed by resin (hashish) and imported outdoor-grown herbal cannabis (marijuana). The content of the psychoactive cannabinoid delta 9-tetrahydrocannabinol (THC) varied widely. The median THC content of herbal cannabis and resin was 2.1% and 3.5%, respectively. The median 13.9% THC content of sinsemilla was significantly higher than that recorded in the UK in 1996/8. In sinsemilla and imported herbal cannabis, the content of the antipsychotic cannabinoid cannabidiol (CBD) was extremely low. In resin, however, the average CBD content exceeded that of THC, and the relative proportions of the two cannabinoids varied widely between samples. The increases in average THC content and relative popularity of sinsemilla cannabis, combined with the absence of the anti-psychotic cannabinoid CBD, suggest that the current trends in cannabis use pose an increasing risk to those users susceptible to the harmful psychological effects associated with high doses of THC.
The quality demands of the pharmaceutical industry require prescription medicines to be consistent in their active ingredient content. Achieving this, using raw cannabis as a feedstock, is especially challenging. The plant material is extremely inhomogeneous, and the ratios of active ingredients are affected by a range of factors. These include the genetics of the plant, the growing and storage conditions, the state of maturity at harvest, and the methods used to process and formulate the material. The reasons for this variability are described, with particular emphasis on the botanical considerations. To produce the complex botanical medicine Sativex®, which contains the cannabinoids Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) and a range of other ingredients, GW Pharmaceuticals had to manage these variables. This medicine, for the treatment of spasticity due to multiple sclerosis, is the first cannabis-based medicine to be approved in the UK. The company's methodology for producing this and other chemotypes is described.
The Yanghai Tombs near Turpan, Xinjiang-Uighur Autonomous Region, China have recently been excavated to reveal the 2700-year-old grave of a Caucasoid shaman whose accoutrements included a large cache of cannabis, superbly preserved by climatic and burial conditions. A multidisciplinary international team demonstrated through botanical examination, phytochemical investigation, and genetic deoxyribonucleic acid analysis by polymerase chain reaction that this material contained tetrahydrocannabinol, the psychoactive component of cannabis, its oxidative degradation product, cannabinol, other metabolites, and its synthetic enzyme, tetrahydrocannabinolic acid synthase, as well as a novel genetic variant with two single nucleotide polymorphisms. The cannabis was presumably employed by this culture as a medicinal or psychoactive agent, or an aid to divination. To our knowledge, these investigations provide the oldest documentation of cannabis as a pharmacologically active agent, and contribute to the medical and archaeological record of this pre-Silk Road culture.
In 2005 and 2008, studies reported that cannabis in England had become dominated by the sinsemilla (unseeded female) form. The average potency (Δ -tetrahydrocannabinol [THC] content) of this material had doubled over the previous decade. Cannabis resin then circulating contained approximately equal ratios of THC and cannabidiol (CBD), whereas sinsemilla was almost devoid of CBD. Despite raised health concerns regarding sinsemilla use and the development of psychotic disorders, no update on street cannabis potency has been published since 2008. A total of 995 seized cannabis samples were acquired from the same 5 constabulary areas included in the 2005 study. The differing forms were segregated, and a representative 460 samples analyzed to assess their cannabinoid content using gas chromatography. The resultant median sinsemilla potency of 14.2% THC was similar to that observed in 2005 (13.9%). In each case, sinsemilla contained minimal CBD. Compared with 2005, resin had significantly higher mean THC (6.3%) and lower CBD (2.3%) contents (p < 0.0001). Although the average THC concentration in sinsemilla samples across the 5 constabularies has remained stable since 2005, the availability of this potent form of cannabis has further increased. Moreover, the now rarer resin samples show significantly decreased CBD contents and CBD:THC ratios, leaving the United Kingdom's cannabis street market populated by high-potency varieties of cannabis, which may have concerning implications for public health.
The floral development and potencies [Δ(9) -tetrahydrocannabinol (THC) contents] of cannabis plants were compared when grown indoors under high-pressure sodium lamps consuming electrical power at three densities (270, 400, and 600 W/m(2)). After a 3-week vegetative phase, plants were grown for 8 weeks, with lamps maintaining an artificial day length of 12 h. Foliar and floral yields were measured. Gas chromatography was used to measure the content of the psychoactive cannabinoid THC. Mean yields per unit of electrical power in each lighting regime ranged from 0.9 to 1.6 g/W, the highest being achieved in the lowest irradiance regime. The individual potencies of the separated leaf and flower materials were not affected by increasing irradiance. However, there was a corresponding increase in the overall potency of the aerial plant tissue. This was because of the plants in brighter conditions producing a higher proportion of floral material.
An apparatus for the measurement of the second virial coefficients of vapours is described. It is designed so that a sample of the gas under investigation can be compared directly with a reference gas (nitrogen). This differential method has practical advantages over direct methods. The apparatus has been used to measure the second virial coefficients of the series of n-alkanes from propane to n-octane from near room temperature to about 140 °C. The results form a family showing deviations from the principle of corresponding states which increase regularly with increasing chain length. A simple formula based on the principle of corresponding states has been found to fit not only the present measurements, but also, previous measurements by other workers at higher temperatures on these substances, and also previous measurements on methane and on ethane. Measurements have also been made on equimolar mixtures of propane +
n
-heptane and of propane +
n
-octane. The results are in much better agreement with a slight extension of a rule of Guggenheim & McGlashan (1951) based on the principle of corresponding states than with the rule of Lewis & Randall (1923)-
Ever-stricter environmental legislation over the past decade has led to the emergence of the end-of-life (EOL) industrial sector, e.g. remanufacturing of products, recycling of material and the recovery of energy. Due to uncertainties over returned product quantities, product quality and product diversity, production planning and control in EOL activities is quite different from those in the forward supply chain. In fact, those uncertainties can be diminished by enhancing the exploitation of the related information generated throughout the product lifecycle. Product lifecycle management provides an opportunity to access and share the distributed information generally available in the product lifecycle, while agent-based systems have been found to be effective tools in such large, uncertain environments. In this article, a product lifecycle information system that deploys agents is introduced into a typical EOL shop floor control system to provide lifecycle information for the returned product for decision-making. Supported by radio frequency identification technology, the product itself controls processes aggressively and autonomously in a system designed to minimise uncertainty. A case study of how the system supports shop floor planning and control in a plastics recycling plant is described at the end of the article.
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