THE STRUCTURAL AND PHYSICAL PROPERTIES OF CRYSTALLINE ANTIBIOTIC MATERIALS

Effectiveness in biological chemical environments virtually defines the term \u27drug\u27 when applied to any attempt to modify that environment by the introduction of an influence in terms of a specific compound or group of compounds. Interest in the configuration of the molecules involved in such modifications led to the X-ray structure determinations, discussed in the thesis, of the following three compounds: (i) 7-chloro-2-methyl-5-phenyl-3-propyl [2,3-b]-imidazolyl quinoline. Derived from the psychoactive drug Librium, it was thought to conform to the structure, containing the highly strained 4-membered monocyclic azete system (Shenoy, a thesis submitted for the degree of Doctor of Philosophy, University of London, 1975), and suggested as one of the first examples of possible stable 4-membered azacyclobutadiene rings. (ii) The methyl ester of 5,5-dimethyl-2-(2-phenoxymethyl-5-oxo-1,3-oxazolin-4-ylidene)-1,3-thiazolidine-4-carboxylic acid

Influence of the Surface Modification of Calcium Carbonate on Polyamide 12 Composites

In previous investigations, it was found that the thermal properties of a polyamide 12 compound can be manipulated, using a designed filler, to improve the melting as well as crystallization behavior, determined for selective laser sintering. A common downside of the introduction of a non-flexing mineral filler is the reduction of the mechanical properties, such as ductility. This paper investigates the influence of content and surface modification of limestone on the mechanical properties. The aim is to understand the effect of an optimized coupling agent on the properties of a compound, containing polyamide 12 filled with 10 wt % of surface modified calcium carbonate. A range of four mineral filler modifications was chosen to investigate their coupling effect, namely 6-amino hexanoic acid, ε-caprolactam, l-arginine or glutamic acid. The in advance surface modified fillers were then each used in combination with the polyamide 12 in a twin-screw extrusion process. With an optimized surface modifying agent, the tensile strength as well as elongation at break can be improved in comparison with uncoated filler implementation, such that up to 60% of the loss of ductility and toughness of a final part when using an untreated filler could be regained using an optimized surface modifier at a correct amount. With the tested filler grade and the specific tested filler amount, the optimized amount of 6-amino hexanoic acid was approx. 2.5 mmol of treatment agent per 100 m2 of CaCO3. These found improvements in a twin-screw extruded polyamide 12 compound show the possible usage of modified calcium carbonate as a functional filler in additive manufacturing and can potentially be transferred in a subsequent investigation in the selective laser sintering process

Impact of Bimodal Particle Size Distribution Ratio of Functional Calcium Carbonate Filler on Thermal and Flowability Properties of Polyamide 12

In previous investigations, it was shown that the melting, as well as crystallization behavior of polyamide 12, could be manipulated by adjusting the particle size distribution of calcium carbonate as a functional filler. It was demonstrated that the melt properties of this compound show a significant dependency on the filler volume-based particle size. As finer and narrower the calcium carbonate particles in the polymer matrix become, the less influence the filler has on the melting properties, influencing the melt flow less significantly than the same surface amount of broad size distribution coarse calcium carbonate filler particles. However, due to increased nucleation, the crystallization behavior on cooling showed a markedly more rapid onset in the case of fine sub-micrometer filler particle size. To control further and optimize the thermal response properties of a filling compound for improved properties in additive manufacturing processing through selective laser sintering, the possibility to combine precisely defined particle size distributions has been studied, thereby combining the benefits of each particle size range within the chosen material size distribution contributes to the matrix. The melt flow at 190 °C, the melting speed, melting and crystallization point as well as crystallization time at 170 °C were analyzed. The thermal and flow properties of a polyamide 12 matrix can potentially be optimized with a combination of a precise amount of coarse and fine calcium carbonate filler. The improvements were exemplified using a twin-screw extruder for compounding, indicating the potential for optimizing functionally filled polymer in additive manufacturing

Identifying the challenges of implementing a European bioeconomy based on forest resources: Reality demands circularity

Jedna od najvažnijih smernica Evropske Unije je smanjivanje gasova koji su uzrok stvaranja efekta 'staklene bašte'. Istraživanje prirodnih zajednica i ekosistema zahteva primenu sistema cirkularne ekonomije u kome bi sirovine prirodnog porekla bile u konstantnoj cirkulaciji ka ponovnom korišćenju otpada. S tim u vezi postavlja se pitanje da li bioekonomija kao jedna od važnih grana realno vodi ka zaštit životne sredine. Pitanja koja dalje proistiću vezana su za to da li je put ka bioekonomiji, koji promoviše Evropska Unija zapravo održiv. Korišćenjem literature, prema Delfi metodi, iz dokumenata Evropske Unije i naučnih publikacija koje su proistekle iz istih, ukazujemo na značaj održivog upravljanja bioresursima, jer deluje da je samo ograničeno smanjenje emisija gasova sa efektom staklene bašte očekivane.Greenhouse gas emission reduction is strongly advocated within the European Union (EU). Biomass has emerged as a renewable energy source and as manufacturing raw material with ecological credentials to mitigate carbon imbalance. The EU has defined the bioeconomy encompassing these material sources as a basis for technological and economic development. Biocenology, describing the study of natural communities, however, additionally demands inclusion of a circular economy, in which it needs to be assumed that endless renewable products are kept in continuous circulation of use and reuse. Thus, there arises the question whether the bioeconomy route alone, promoted by the EU, is sustainable. Using research literature, based on the Delphi method, and EU documents, we discuss the importance of sustainable management of bioresources. Short term solutions may remain necessary to ensure economic stability but, without embracing the circular economy, only limited mitigation of greenhouse gas emissions can be expected

Identifying the challenges of implementing a European bioeconomy based on forest resources: Reality demands circularity

Jedna od najvažnijih smernica Evropske Unije je smanjivanje gasova koji su uzrok stvaranja efekta 'staklene bašte'. Istraživanje prirodnih zajednica i ekosistema zahteva primenu sistema cirkularne ekonomije u kome bi sirovine prirodnog porekla bile u konstantnoj cirkulaciji ka ponovnom korišćenju otpada. S tim u vezi postavlja se pitanje da li bioekonomija kao jedna od važnih grana realno vodi ka zaštit životne sredine. Pitanja koja dalje proistiću vezana su za to da li je put ka bioekonomiji, koji promoviše Evropska Unija zapravo održiv. Korišćenjem literature, prema Delfi metodi, iz dokumenata Evropske Unije i naučnih publikacija koje su proistekle iz istih, ukazujemo na značaj održivog upravljanja bioresursima, jer deluje da je samo ograničeno smanjenje emisija gasova sa efektom staklene bašte očekivane.Greenhouse gas emission reduction is strongly advocated within the European Union (EU). Biomass has emerged as a renewable energy source and as manufacturing raw material with ecological credentials to mitigate carbon imbalance. The EU has defined the bioeconomy encompassing these material sources as a basis for technological and economic development. Biocenology, describing the study of natural communities, however, additionally demands inclusion of a circular economy, in which it needs to be assumed that endless renewable products are kept in continuous circulation of use and reuse. Thus, there arises the question whether the bioeconomy route alone, promoted by the EU, is sustainable. Using research literature, based on the Delphi method, and EU documents, we discuss the importance of sustainable management of bioresources. Short term solutions may remain necessary to ensure economic stability but, without embracing the circular economy, only limited mitigation of greenhouse gas emissions can be expected

On the role of API in determining porosity, pore structure and bulk modulus of the skeletal material in pharmaceutical tablets formed with MCC as sole excipient

The physical properties and mechanical integrity of pharmaceutical tablets are of major importance when loading with active pharmaceutical ingredient(s) (API) in order to ensure ease of processing, control of dosage and stability during transportation and handling prior to patient consumption. The interaction between API and excipient, acting as functional extender and binder, however, is little understood in this context. The API indomethacin is combined in this study with microcrystalline cellulose (MCC) at increasing loading levels. Tablets from the defined API/MCC ratios are made under conditions of controlled porosity and tablet thickness, resulting from different compression conditions, and thus compaction levels. Mercury intrusion porosimetry is used to establish the accessible pore volume, pore size distribution and, adopting the observed region of elastic intrusion-extrusion at high pressure, an elastic bulk modulus of the skeletal material is recorded. Porosity values are compared to previously published values derived from terahertz (THz) refractive index data obtained from exactly the same tablet sample sets. It is shown that the elastic bulk modulus is dependent on API wt% loading under constant tablet preparation conditions delivering equal dimensions and porosity. The findings are considered of novel value in respect to establishing consistency of tablet production and optimisation of physical properties

Analysis of anisotropic pore structures using terahertz spectroscopy and imaging

This study demonstrates the analysis of anisotropic pore structures of highly porous pharmaceutical powder compacts by combining terahertz time-domain spectroscopy and in-situ measurements of the liquid penetration using terahertz pulsed imaging

A structure parameter for porous pharmaceutical tablets obtained with the aid of Wiener bounds for effective permittivity and terahertz time-delay measurement.

A structure parameter that can be used to predict the pattern of arrangement of porous inclusions in pharmaceutical tablets is introduced. By utilizing the effective refractive index of a pharmaceutical tablet obtained from terahertz time-domain measurements, we have shown that there exists a promising correlation between the calculated structural parameter and the porosity of training sets of pharmaceutical tablets, having well-defined characterization. Knowing of the structural arrangement, i.e. combined constituent skeletal-pore elements in series, parallel or mixed within porous media, could serve as a basis for understanding the ingress and permeation of liquids in such media. In the realm of pharmaceutical applications, such knowledge of the structural arrangement of air voids within a medicinal tablet could enable correlation with mechanical strength and dissolution behaviour in aqueous systems.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ijpharm.2016.04.02

Challenges of implementing a European bioeconomy based on forest resources: need for circularity

Greenhouse emission reduction is strongly advocated within the European Union. The study of natural communities (biocenology), additionally demands inclusion of a circular economy, in which renewable products are kept in continuous circulation of use and reuse. In light of this, there arises the question whether the bioeconomy route alone, promoted by the EU, is sustainable. Using literature, based on the Delphi method, from EU documents and related scientific literature , we highlight the importance of sustainable management of bioresources. It seems that only limited mitigation of greenhouse gas emissions can be expected

Regulatory Paradigm and Challenge for Blockchain Integration of Decentralized Systems: Example—Renewable Energy Grids

Nowadays, fossil fuels are used in a clearly unsustainable way that can bring potentially catastrophic consequences. Electricity is currently delivered to end users by generation and energy transmission companies. Previous research shows that the development of modern circular economy sets a need for the re-orientation of socio and economic development of decentralized systems, including energy basis. In addition to being ecological, the use of renewable energy sources also has economic significance by contributing to energy independence. Citizens, industries, local and national authorities become interconnected within emerging novel renewable energy sourcing communities, through which they establish trade of energy and, most importantly, models of investing and reshaping the distribution of renewable energy. The modern portfolio management of renewable energy networking is aiming toward decentralized systems of trade, where the consumer becomes a producer (prosumer) within the network, itself managed by users. Excess energy produced in the micro-grid nets within the over-arching national and transnational energy grid should be accounted for and managed with blockchain technology for financial and structural security. The decentralization of the energy market requires the establishment of strict norms that will regulate the market and taxation of profits arising. The extensive literature review on blockchain in the energy sector reflects a very pragmatic and narrow approach to the topic, although it is evident that the distribution of energy within the blockchain would enable economic development through reducing cost and ensuring more secure energy trade. Blockchain technology embeds the related digital codes, in which information will be visible to all, but also secured from hacking and duplicating. However, there are challenges to this paradigm, not least the energy consumption of the extensive nodal mesh required to perform the necessary protocols. This paper aims to provide an overview of the application of blockchain technology and the need for the development of the regulatory system and of potential solutions to the challenges posed. By undertaking an energy consumption analysis of blockchain implementation from first electronic principles, which has not been constructed before in the literature, this paper’s conclusion stresses the future demand for reducing energy consumption and considers the latest findings in the quantum coupling of light signals as a potential for solving the enormous ledger duplication structure problem