Agro-Industrial Waste Materials as Substrates for the Production of Poly(3-Hydroxybutyric Acid)

Accumulation of recalcitrant plastics in the environment has become a world-wide problem in today’s societies. Rapid depletion of natural resources for synthetic plastics along with environmental concerns has directed research towards finding alternatives to petroleum-based polymers. Poly(3-hydroxybutyric acid) P(3HB), as one of these alternatives, have attracted much attention in recent years due to their varied mechanical properties, biocompatibility and iodegradability. The aim of this study was to identify an agro-industrial waste resource economically suitable for large-scale production of P(3HB), to optimize the production using Response Surface Methodology in small-scale and subsequently, to test the production in a continuously stirred tank reactor. Among a range of agro-industrial waste, orange peel was selected as the most suitable for P(3HB) production. P(3HB) concentration of 1.24 g P(3HB)/L culture broth with 41% P(3HB)/dcw yield was obtained using orange peel as the sole carbon source in optimized medium with a modified strain of Bacillus subtilis (B. subtilis OK2)

Dual biopolymer production and separation from cultures of Bacillus spp.

In the search of alternative new materials for biodegradable plastics, biopolymers provide attractive solutions with their vast range of applications. A challenge in industrial production of biopolymers is their high cost, and one approach to minimise the cost is expanding the number of valuable products obtained from a single batch. The aim of this thesis was the dual production of biopolymers, P(3HB) and γ-PGA from cheap substrates with the view to lay grounds for a feasible, innovative, low cost production process. A common denominator between the two biopolymers focused in this thesis, (P(3HB) and γ-PGA), was that they both could be produced by Bacillus sp. One out of five strains screened, Bacillus subtilis OK2, was selected and the structures of both biopolymers produced were confirmed. Subsequently, optimisation of the production medium via statistical optimisation tools, and scaling-up of the process from shaken flasks to fermenters were carried out. Statistical design tool Placket Burman (PB), (Design Expert 6.0), was used to determine the effect of medium components on γ-PGA and P(3HB) production and to identify the crucial medium components in production media. The outcome of PB analysis of dual polymer production did not match the PB analysis of single polymer production. Considering the complexity of the dual polymer production mechanism, central composite design was applied after the number of parameters was reduced from five to three. A medium composed of 20 g/L glucose, 1.5 g/L yeast extract, 2.4 g/L citric acid, 32 g/L glutamic acid and 12 g/L ammonium sulphate was identified as the dual polymer production medium. Using an inoculum medium different from the production medium proved to have a positive effect on the production. Consequently, 1 g/L P(3HB) and 0.4 g/L γ-PGA in shaken flasks and 0.6 g/L P(3HB) and 0.2 g/L γ-PGA in single batch fermenters were produced with the strain Bacillus subtilis OK2. Selection of biowaste for the dual production was conducted using four biowastes; rapeseed cake, wheat bran, Spirulina powder and orange peel; using four pre-treatment methods, acid treatment, alkaline treatment, water infusion, and microwave exposure. γ-PGA production could not be detected when any of the waste materials was used as a sole medium component. Orange peel using water infusion pre-treatment was found to be the most suitable biowaste for the production of P(3HB). Bioreactor experiments showed that 1.24 g/L P(3HB) could be produced using orange peel as carbon source supplemented with yeast extract and citric acid. Dual polymer production using orange peel as carbon source proved to be more challenging as some of the ingredients in orange peel interfered with the dual production and inhibited production of both polymers. Although the different sugars in orange peel had a positive effect on production, pH control coupled with DOT control proved to be essential to overcome inhibition and 0.2 g/L of each polymer were produced in 79 h. For the separation of the two polymers from the culture broth, magnetic field, floatation, and sedimentation methods were investigated. Exposure to magnetic field was found to be inhibitory for P(3HB) production. The use of floatation and sedimentation for the online separation of cells with and without polymer to facilitate a recycle strategy exhibited negative results. This was found to be due to cells undergoing cell lyses at the early stages of the fermentation releasing P(3HB) granules into the fermentation medium. The size distribution of these granules was identified. The results elicit the possibility of using cell auto-lysis behaviour for the separation of the two polymers from the culture broth leading to a reduction of costs

A Strategy for Dual Biopolymer Production of P(3HB) and γ-PGA

BACKGROUND Production of biopolymers has gained considerable attention because of their biodegradability, biocompatibility, and as suitable replacements for mineral-based polymers. Despite advances in production process, a notable drawback still exists due to high production cost. The aim of this paper is to provide a production strategy for cost reduction. The suggested process may be adopted to other polymers, useable to wide audience in biopolymer research. RESULTS Dual production of two commercially important biopolymers, P(3HB) and γ-PGA, in a single batch from cheap substrates was studied, as proof of concept, for a feasible low cost dual biopolymer production. The dual production from a single batch yielded 1 g/L P(3HB) and 0.4 g/L γ-PGA using Bacillus subtilis OK2 (B. subtilis OK2). When orange peel was substituted as a cheap carbon source for dual production, coupled pH and dissolved oxygen control proved to be essential to overcome the inhibition imposed by the non-sugar components of the substrate. The cell lysis and release of P(3HB) granules in the dual production medium can be exploited of as a new approach for separation of this polymer. CONCLUSION This proof of concept study provides a new approach from upstream to downstream processing for low cost production of dual biopolymers

Augmented Reality Interfaces for Enabling Fast and Accurate Task Localization

Changing viewpoints is a common technique to gain additional visual information about the spatial relations among the objects contained within an environment. In many cases, all of the necessary visual information is not available from a single vantage point, due to factors such as occlusion, level of detail, and limited field of view. In certain instances, strategic viewpoints may need to be visited multiple times (e.g., after each step of an iterative process), which makes being able to transition between viewpoints precisely and with minimum effort advantageous for improved task performance (e.g., faster completion time, fewer errors, less dependence on memory). Many augmented reality (AR) applications are designed to make tasks easier to perform by supplementing a user's first-person view with virtual instructions. For those tasks that benefit from being seen from more than a single viewpoint, AR users typically have to physically relocalize (i.e., move a see-through display and typically themselves since those displays are often head-worn or hand-held) to those additional viewpoints. However, this physical motion may be costly or difficult, due to increased distances or obstacles in the environment. We have developed a set of interaction techniques that enable fast and accurate task localization in AR. Our first technique, SnapAR, allows users to take snapshots of augmented scenes that can be virtually revisited at later times. The system stores still images of scenes along with camera poses, so that augmentations remain dynamic and interactive. Our prototype implementation features a set of interaction techniques specifically designed to enable quick viewpoint switching. A formal evaluation of the capability to manipulate virtual objects within snapshot mode showed significant savings in time spent and gain in accuracy when compared to physically traveling between viewpoints. For cases when a user has to physically travel to a strategic viewpoint (e.g., to perform maintenance and repair on a large physical piece of equipment), we present ParaFrustum, a geometric construct that represents this set of strategic viewpoints and viewing directions and establishes constraints on a range of acceptable locations for the user's eyes and a range of acceptable angles in which the user's head can be oriented. Providing tolerance in the allowable viewing positions and directions avoids burdening the user with the need to assume a tightly constrained 6DOF pose when it is not required by the task. We describe two visualization techniques, ParaFrustum-InSitu and ParaFrustum-HUD, that guide a user to assume one of the poses defined by a ParaFrustum. A formal user study corroborated that speed improvements increase with larger tolerances and reveals interesting differences in participant trajectories based on the visualization technique. When the object to be operated on is smaller and can be handheld, instead of being large and stationary, it can be manually rotated instead of the user moving to a strategic viewpoint. Examples of such situations include tasks in which one object must be oriented relative to a second prior to assembly and tasks in which objects must be held in specific ways to inspect them. Researchers have investigated guidance mechanisms for some 6DOF tasks, using wide--field-of-view (FOV), stereoscopic virtual and augmented reality head-worn displays (HWDs). However, there has been relatively little work directed toward smaller FOV lightweight monoscopic HWDs, such as Google Glass, which may remain more comfortable and less intrusive than stereoscopic HWDs in the near future. In our Orientation Assistance work, we have designed and implemented a novel visualization approach and three additional visualizations representing different paradigms for guiding unconstrained manual 3DOF rotation, targeting these monoscopic HWDs. This chapter includes our exploration of these paradigms and the results of a user study evaluating the relative performance of the visualizations and showing the advantages of our new approach. In summary, we investigated ways of enabling an AR user to obtain visual information from multiple viewpoints, both physically and virtually. In the virtual case, we showed how one can change viewpoints precisely and with less effort. In the physical case, we explored how we can interactively guide users to obtain strategic viewpoints, either by moving their heads or re-orienting handheld objects. In both cases, we showed that our techniques help users accomplish certain types of tasks more quickly and with fewer errors, compared to when they have to change viewpoints following alternative, previously suggested methods

D1 dopamine receptor activity is not altered by a mutation in the first intracellular loop

AbstractThe first intracellular loop of the G protein-coupled receptors (GPCRs) is probably the domain that has been studied least. According to the limited data available, mutations of this region can increase, decrease or not affect receptor-G protein coupling, depending on the receptor. Melanocyte-stimulating hormone (MSH) receptors with a Ser69Leu mutation of the first intracellular loop phenotypically confer tobacco color to the coat of mice, and have constitutive activity and enhanced agonist stimulation of adenylyl cyclase. Since the human D1 dopamine receptor (D1DR) has a serine at the equivalent position, we were interested to see if this serine is involved in receptor-G protein coupling in a similar fashion. Our site-directed mutagenesis study showed that the replacement of this serine by leucine (Ser56Leu) in D1DR did not affect the ability of the receptors to bind ligand or couple to G protein

Attitudes and opinions of Head Start trainees toward children and selected training procedures as reflected in group discussions

Call number: LD2668 .R4 1967 S94

A legal study of internet advertisement: medicine / Nurul Haizan Sukan and Marina Pilus

Medicine online advertisement has raised concern on consumer safety and wellness as the information contained in the advertisements can be misleading and false. Existing laws which govern medicine online advertising seem inadequate and inefficient to encounter the problems, and therefore it has limited the power of enforcement. Whereas medicine’s advertising via the internet is on the rise. Therefore, it is important to study whether the existing laws in Malaysia are comprehensive enough to protect consumers from false advertisements relating to medicines. Thus, the research objective is to reform the laws involved in medicinal advertisements. This study has examined the relevant laws and regulations in Malaysia so as to reveal gaps in existing knowledge, which has filled out of the research. The methodology used in this study is qualitative research. The primary resources such as Acts in Malaysia, UK, US and Singapore were analyzed. Secondary resources such as articles and journals were reviewed. Then empirical research was also carried out by conducting interviews with respondents from the Ministry of Health (MOH) and Federation of Malaysian Consumers Associations (FOMCA) as well as surveys from the consumers themselves. The analysis of laws, respondents’ interviews and consumer surveys have indicated that the current laws are not comprehensive to control the online advertising of medicine which resulted in the lack of enforcement power. The research findings confirm that there are lacunas in the existing law governing the medicine’s internet advertising. Therefore, we recommend a law reform

Estimation of wavelet threshold value for surface EMG baseline removal

High quality of surface electromyography is vital during investigation on muscle activity. Low quality of surface EMG signals causes extracted signals to be inaccurate and lead to misinterpretation and misclassification of the signals. A surface EMG signal quality is determined by the ratio of muscle contraction to its baseline during muscle relaxation period. Baseline noises are originated from powerline, cable motion artefact, electronics of the amplification systems and skin-electrode interface. The noises are quite difficult to be removed by digital or active filter since they do not have specific frequency range like powerline interference and corner frequency noise. However, wavelet de-noising enables users to remove noise by accessing both frequency and time information. Baseline surface EMG noise is possible to be removed by estimating de-noise threshold based on mean absolute value and root mean square of its baseline. The result of this study shows that the proposed estimation of threshold method is better than the conventional threshold setting