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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vliv skladování na změny obsahových látek konopí

Vomáčka, Vít January 2017 (has links)
This thesis deals with the effect of storage of cannabis on the level of content of its active substances. The theoretical portion focuses on a botanical characteristics sum-mary. It further describes the growing needs and options of cannabis on the fields and of medical cannabis in covered areas. Portion of the thesis deals with the use of each individual parts of the cannabis plant. The thesis contains detailed description of canna-binoids and other substances. It further describes the effect of individual external factors on the stability of cannabinoids in cannabis products. The last part of the theore-tical section deals with the ability to analyze cannabinoids. The goal of the experimental section was to discover effects of different type of storage on the level of content of cannabidiol and delta-9-tetrahydrocannabinol in cannabis samples. The setting included a gas chromatograph GC Fisons instruments with FID detector. These samples were regularly collected and ex-tracted during the period of one year. Retention periods of individual cannabinoids and calibration curves were created. The results showed a reduction of cannabinoids in higher temperatures. The results further confirmed storage of vacuumed materials at -20 °C temperature as the most appropriate type of storage for female inflorescence of can-nabis.
12

Are All THC-Dominant Cannabis Varieties the Same? Comparing the Phytochemistry and Bioactivity of Different THC-Dominant Cannabis Samples

Waldbillig, Adam 29 August 2022 (has links)
Cannabis sativa has a complex history of classification and traditional use. Cannabis sativa ssp. sativa and spp. indica are the two major lineages of cannabis and, through artificial selection, many strains or cultivars are found within each group are bred together to yield hybrid plants. New methods of classification based on Δ⁹-Tetrahydrocannbinol (THC) and Cannabidiol (CBD) content as well as minor cannabinoids and terpenes have emerged as a more effective classification of cannabis. However, the fidelity of cannabis varieties relative to their respective strain names and lineages (indica, sativa and hybrid) based on chemistry has been brought into question. THC and more recently CBD are collectively responsible for the psychoactive and therapeutic effects of cannabis and minor cannabinoids and terpenes are emerging as having their own unique bioactivity or synergistic effects in vitro. Considering the variation in cannabis chemical profile and infidelity to strain names or lineages, we investigated the cannabinoid, terpene and metabolomic profiles of 33 THC-dominant strains (113 samples) to evaluate existing and alternative chemistry-based classification systems using multivariate analyses. Here, we conclude that Indica-Sativa-Hybrid designations are insufficient in describing variation in cannabinoid, terpene and metabolomic data, and that a terpene-based profile classification revealed robust groupings in cannabinoid-terpene data. However, terpene profiles were not discernable in metabolomic data. To investigate how chemical complexity and variability impacts bioactivity, we compared the activity of cannabis extracts to that of pure THC (and CBD) to determine if THC alone is driving activity. THC, CBD, and plant extracts were tested in vitro for cytotoxicity in BEAS-2Bs cells and for cannabinoid receptor signalling activity using a human CB₁-HEK293 cell model. THC did not completely dictate 24-hour toxicity in BEAS-2B cells suggesting that other extract components (beyond THC and CBD) are contributing to cytotoxicity. While CBD alone was 2x more toxic than THC alone, THC:CBD do no predict toxic concentration. THC within extracts appeared to drive efficacy at CB₁ receptors by reducing intracellular cAMP accumulation but did not dictate variation in EC₅₀. THC in extract also appeared to increase percent cAMP reduction in cells regardless of low CBD content but a 1:1 balanced THC/CBD extract revealed reduced percent cAMP reduction. Pure compounds compared to extracts of the same THC/CBD ratio performed very similarly at CB1 receptors besides 1:1 extract preparation having reduced % reduction of cAMP compared to 1:1 pure compounds suggestive of NAM by extract components. Regression modelling of THC within extract revealed a significant positive relationship in % cAMP reduction (Emax) but no significance in TC₅₀ and EC₅₀. This work demonstrates the importance of rigorous analysis of cannabis chemistry as well as evaluation of extracts in bioactivity assays.
13

Comparing Extraction Methods in Sample Preparation for the Quantification of Cannabinoids in Industrial Hemp

Sandbrook, Ann Marie 28 May 2021 (has links)
Industrial hemp is legally defined in the United States by the Agriculture Improvement Act of 2018 (2018 Farm Bill) as Cannabis containing <0.3% total tetrahydrocannabinol (THC). The 2018 Farm Bill does not, however, specify standard methods for sample preparation or quantification of cannabinoids (including THC) in Cannabis. Extraction efficiency of phytochemicals is well-known to depend on the solvent and extraction method used. In this project, we evaluated the effect of sample preparation extraction methods on the quantitative analysis of five cannabinoids found in industrial hemp with regulatory or commercial significance: cannabidiol (CBD), cannabidiolic acid (CBDA), delta-9-tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), and cannabinol (CBN). Extraction methods evaluated include: QuEChERS, diethyl ether, ethanol, and methanol. Extracts obtained via these methods were subject to quantitative cannabinoid analysis by UPLC/PDA. Standard curves for quantification of each cannabinoid were constructed using authentic standards for quantification. The concentrations of each cannabinoid in the plant material determined via each of the extraction methods were compared using one-way ANOVA followed by Tukey's HSD (significant difference defined as p <0.05). All extraction methods evaluated returned different concentrations of total THC in the plant material. The QuEChERS extraction resulted in the highest calculated concentrations of THC, THCA and CBDA, reporting three to four times greater than obtained via other extractions evaluated. Classification of the starting plant material as hemp or marijuana depended on the extraction method used. These findings clearly and quantitatively demonstrate the need for standardization of extraction methods for hemp analysis and regulation. / Master of Science in Life Sciences / Hemp is a type of Cannabis plant that produces an insignificant amount of the psychoactive cannabinoid tetrahydrocannabinol (THC). Hemp was federally illegal in the United States until the 2018 Farm Bill differentiated hemp from Marijuana, defining hemp as containing less than 0.3% total THC. Standard methods for cannabinoid testing in hemp have not been defined. In this project, four extraction methods with potential use for sample preparation in hemp analysis were evaluated and compared. The extraction methods evaluated included: ethanol, methanol, QuEChERS, and diethyl ether. The concentrations of cannabinoids in each of the plant extracts were then determined using an appropriate analytical method and authentic standards for Cannabidiol (CBD), Cannabidiolic Acid (CBDA), THC, Tetrahydrocannabinolic Acid (THCA), and Cannabinol (CBN). Total concentrations of each cannabinoid in the plant material were then calculated using each extraction method. All extraction methods evaluated resulted in different concentrations of total THC in the plant material, with QuEChERS resulting in the highest calculated concentrations of THC, THCA, and CBDA. The identify of this plant material as hemp or marijuana depended on the extraction method used. This result is not surprising, as extraction efficiency of phytochemicals is well known to depend on the solvent and extraction method used. Nonetheless, our findings clearly demonstrate the need for standardization of extraction methods for hemp analysis and regulation.
14

Kontorsflytt från Stockholms CBD - En studie om påverkan på kontorsmarknaden / Office relocation from Stockholm CBD - A study on the impact of the office market

Kyhälä, Jari, Käck, Christian January 2013 (has links)
Både storbanker och statliga myndigheter har valt att göra omlokaliseringar av sina verksamheter i Stockholmsområdet. Dessa aktörer har länge haft sina huvudkontor inom Stockholm Central Business District (CBD), men kommer från och med årsskiftet 2013/2014 att samla hela eller delar av sina verksamheter utanför området. Under de kommande fyra åren blir över 210 000 kvadratmeter kontorslokaler lediga, vilket både skapar utmaningar och möjligheter för de berörda fastighetsägarna. Den här studien har tre viktiga utgångspunkter: Faktorerna bakom flytt för banker och myndigheter, hur Stockholms kontorsmarknad kommer att ändras i fortsättningen och på vilket sätt Stockholms CBD utvecklas när de vakanta kontorslokalerna byggs om. De bakomliggande resonemangen kring besluten om att flytta från området skiljer sig väsentligt åt mellan de intervjuade aktörerna. Den främsta anledningen till att myndigheterna samlar olika verksamhetsdelar i Solna respektive Telefonplan är ekonomiska besparingar. Bankernas främsta anledning är att koncentrera sina verksamheter inom ett geografiskt område. Nordea väljer att stanna kvar i CBD medan Swedbank flyttar ut. För dem är samlokaliseringen en del av att effektivisera det dagliga arbetet. För fastighetsägarna i området innebär det stora ombyggnations- och renoveringsprojekt i lokalerna som tomställs. Det finns däremot inget i studien som tyder på att företag vill samlokalisera sina verksamheter i kluster med andra aktörer inom samma bransch. I och med den omstrukturering som påbörjas kan Stockholms stad tillsammans med fastighetsägarna genom detaljplanering förändra och utveckla staden. Dessa åtgärder kan förhoppningsvis i framtiden ge en mer livfull stadskärna för Stockholm och nya, mindre företag får möjlighet att etablera sig i CBD. / Major banks and authorities have decided to relocate their headquarters in the Stockholm area. The big companies in Stockholm have always been located in the most central parts of the city, the Central Business District (CBD). In the beginning of 2014 the companies starts to move their business outside CBD. This process will proceed the next four years and there will be more than 210 000 square meters of office space available. These relocations create challenges and opportunities for the property owners in the area. The study has three important aspects: The reason behind the moving of banks and authorities, how this affects the office market in Stockholm CBD and the property development as well as the growth of the city center. The reason behind the moving decision is very different depending on which company we asked. The main reason why authorities relocate their business to Solna and Telefonplan are economic cut downs. The banks most common reason to relocate is to concentrate their activities to one particular area. Nordea decided to stay in CBD and Swedbank is heading toward Sundbyberg. Their most important reason to move is to rationalize and develop their daily work. For the property owners there will be huge renovation and reconstruction challenges when the tenants leave the buildings. All the property owners have a common opinion that a higher vacancy rate is welcome, because of the extremely low vacancies in the area. There is no tendency on the market which indicates that companies want to relocate their business in a cluster with other companies in the same industry. As a result of the reconstruction in the area, Stockholm Municipality and the property owners have a great opportunity to develop a new local plan to improve the capital of Sweden
15

The factors that influence the performance of a regional shopping centre.

Goldberg, Michelle Sherene 17 March 2014 (has links)
No description available.
16

A Study of Rental and Vacancy Rate in Office Market of CBD and Suburban Technology Park- A Case Study of the Taipei Office Market

Chan, Chung-man 25 August 2011 (has links)
Office is a necessary workplace for corporate business operation in current commercial market, the maturity of office market development reflects the economy and commercial development status in different markets. The application of transacted office rental and vacancy rate as a primary data is relatively rare in pervious domestic literatures due to the difficultly of primary data collection. Therefore, the study of the correlation between office rental and vacancy rate by using primary data analysis is one of the research focus. Moreover, the lack of land supply for office development in Taipei CBD led to a rapid growth for suburban technology parks in the past decade. Corporate occupiers may relocate from the CBD to suburban technology parks due to competitive rental, improved public transportation network and information technology infrastructure. Therefore, the study of the correlation between suburban technology parks¡¦ office new supply and CBD Grade A office vacancy rate is another research focus in this thesis. The scope of study covers the Taipei CBD office submarkets and Neihu Technology Park and Nankang Software Park within suburban of Taipei City. The research method includes a literature review, market overview of CBD and suburban technology parks and empirical analysis of research data. By using correlation coefficient and ordinary least squares methods to analyze the factors, there are two finding revealed in the empirical results. Firstly, the empirical results revealed that the relationship between Taipei CBD Grade A office rental and vacancy rate is negative. Rental drop while vacancy increasing and oppositely rental increase while vacancy rate decline. The grade A rental may drop NT$27.16 per ping per month when Grade A vacancy rate increase 1%. Secondly, the empirical results revealed that the relationship between suburban technology parks¡¦ office new supply and CBD Grade A office vacancy rate is positive. The Grade A office vacancy rate may increase 1.53% when suburban technology parks increase 10,000 pings office new supply. NT$27.16 per ping per month when grade A vacancy rate increase 1%. It would be helpful for making business decisions on office leasing, real estate development and property investment if corporate occupiers, real estate developer and investor have more knowledge on office market vacancy rate and new supply information.
17

A study of cadmium sulfide thin film grown by chemical bath deposition

Jhang, Jhen-Chang 27 July 2006 (has links)
In this study , we investigate the relationship between growth condition and thin film quality of cadmium sulfide (CdS) thin films grown by chemical bath deposition (CBD) method. Thin film structures are analyzed by X-ray diffraction , morphology and grain size are obtained by scanning electronic microscopy , and film thickness measured by reflectance spectroscopy . In medium pH value ( pH=10.5) , 20 min deposition can achieve 450 nm film thickness . At lower pH (pH=8.5), low hydrolysis rate of thiourea limits the concentration of sulfur anion , film thickness is only 49 nm after one hour deposition at 70 ¢J , and the obtained thin film can not fully cover the substrate to have a pin-hole free film . At higher pH (pH=11), 40 min only deposites 100 nm film thickness. Strong binding between the cadmium ion and the complexing agent causes low free cadmium cation concentration in the solution, which limits the growing rate. By varying the growth pH condition, the difference in thickness is more than one order of magnitude. In contrast to the film thickness relationship, grain size distribution suffers less influence from the pH consition. Our results indicate no explicitly relation between the grain size and solution pH condition. 20 minutes depositions result cadmium sulfide grain sizes to be 70¡Ó10nm , and 40 minutes result grain size to be 75¡Ó15nm . The results indicate that film thickness increases mainly due to the increasing of grain number, rather than the increasing of grain size . By summarized the results, we propose that the deposition of cadmium sulfide film is initially formed homogeneous nucleation in the solution. The nuclea diffuse and adhere to the substrate. Intristic electric dipole momentum of the cadmium sulfide nano-particle provides an attractive force for the adhesion, and results preferred orientation. Meanwhile, the grain keeps growing up until the size saturated .
18

CARACTERIZAÃÃO ÃTICA E ESTRUTURAL DE FILMES DE CdS DEPOSITADOS POR BANHO QUÃMICO

Wellington de Queiroz Neves 15 March 2013 (has links)
Neste trabalho estudamos as propriedades Ãticas de filmes de sulfeto de cÃdmio (CdS) crescidos sobre um substrato de vidro. Os filmes foram obtidos por meio da tÃcnica de deposiÃÃo por banho quÃmico (Chemical Bath Deposition, CBD). Os filmes de CdS sÃo preparados numa soluÃÃo aquosa, sob agitaÃÃo, a uma temperatura de 80 oC durante 60 minutos sobre substrato de vidro. Alguns dos filmes foram obtidos com duplo depÃsito em dois banhos sucessivos iguais. Como fonte de Ãons de cÃdmio à usado sulfato de cÃdmio (CdSO4,) como fonte de Ãons de enxofre à usado a tioureia, como tampÃo à usado cloreto de amÃnia, e como agente complexante o Ethylenediamine tetra acetic acid (Edta) em vÃrias concentraÃÃes. ApÃs o crescimento, os filmes foram submetidos a um tratamento tÃrmico no ar nas temperaturas de 300 ou 400 oC por uma hora. Foram realizadas medidas experimentais usando a tÃcnicas de difraÃÃo de raios-X, fototransmissÃo Ãtica UV-VIS e espectroscopia Raman. Os filmes de CdS obtidos possuem estrutura cÃbica e sÃo de coloraÃÃo amarelada, homogÃneos e muito aderentes ao substrato de vidro. SÃo analisados os efeitos da concentraÃÃo de Edta, tratamento tÃrmico no ar, tempo de deposiÃÃo e temperatura de crescimento dos filmes de CdS. Nossos resultados mostram que, sob as condiÃÃes estudadas, os filmes de CdS nÃo possuem fase hexagonal em sua estrutura. O gap dos filmes de CdS està em torno de 2,45 eV, com pequenas variaÃÃes (2,40 â 2,51 eV) devido Ãs condiÃÃes experimentais de crescimento ou tratamento tÃrmico apÃs o crescimento. Observamos o modo LO, de simetria A1, em torno de 300 cm-1 e atà trÃs sobremodos desse fÃnon. Em alguns casos, os espectros Raman aparecem sobre uma larga fotoemissÃo, dependendo das condiÃÃes experimentais.
19

Vitality square - creating a healthy environment in the Pretoria CBD

Verster, Alet 07 December 2009 (has links)
This thesis deals with the creation of holistically healthy environments in an urban context. The Pretoria Central Business District (CBD) is the focus area, as this is where many people spend their working hours in offices. This thesis proposes a vitality centre where healthy environments and healthy lifestyles are made available to these workers. This should become an urban oasis which caters to the vitality of the mind, body and spirit. The hypothesis argues that the problems associated with unhealthy environments in buildings can be alleviated through the connection of people with nature and its forces. The focus is not only on the physical, but also on the metaphysical quality of architecture and its influence on the user. The four elements of nature (light, air, earth and water) are invited into the building. Their associative qualities are exploited to create an awareness of the presence of nature, even in an urban context. On a physical level, this association implies the use of natural light, natural ventilation and contact with nature in the built environment. / Dissertation (MArch(Prof))--University of Pretoria, 2010. / Architecture / unrestricted
20

Právní režim ochrany biodiverzity mořského dna za hranicemi národní jurisdikce / Legal regime of Marine Biodiversity Conservation in Areas beyond National Jurisdiction

Majovská, Barbara January 2017 (has links)
The seabed has long been an unexplored area and we still do not have all the information about its environment. In the second half of the 20th century, the development of technology allowed a better exploration of the seabed. There have been discovered seamounts, hydrothermal vents and other formations. Around these formations there are rich ecosystems that are currently threatened by mining, deep-sea fishing, bioprospecting and deep-sea tourism. Most of the seabed is beyond the area of national jurisdiction and currently there is no legal convention aimed at protecting this area. This thesis explains the concept of biodiversity, its significance and threats. The main legal instruments for the protection of the seabed biodiversity are analysed. These include the 1982 United Nations Convention on the Law of the Sea, the so-called Constitution for the oceans. At the time of the adoption of this Convention, activities on the seabed were still being developed. The UNCLOS Convention therefore regulates only the activities of exploration for and exploitation of the resources on the seabed beyond national jurisdiction, in the Area. The importance of the UNCLOS Convention for the protection of the marine environment was therefore limited. Due to the activities of The International Seabed Authority and The...

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