The effects of pH-stat long-term lactic acid bacterial activity prior to curd formation on the development of cheese structure in a fat free model cheese : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Food Technology at Massey University, Manawatu, New Zealand

Most Figures from published sources have been removed for copyright reasons but may be accessed via their source listed in the References. Figures 2-1, 2-32, 2-33 do not have an accessible source and therefore remain. Corresponding Figures from journal sources are as follows: Fig 2.4 (=Dalgleish, 2011 Fig 5; Fig 2.18 (=Dalgleish & Corredig, 2012 Fig 4 a & b); Fig 2.20 (=Bech, 1993 Fig 4); Fig 2.21 (=McSweeney, 2004 Fig 5); Fig 2.22 (=Sousa et al., 2001 Fig 1); Fig 2.24 (=Tunick, 2000 Fig 3); Fig 2.26 (=Tunick, 2000 Fig 1); 2.28 (Waungana et al., 1998 Fig 2); Fig 2.29 (=Guinee et al., 1998 Fig 1); Fig 5.11 (=Piraino et al., 2007 Fig 1 e & f & b); & Fig 5.14 (=Lane & Fox, 1997 Fig 6).Cheese ripening is an important step in most cheese production practices during which a tasteless fresh cheese is converted to a tasty and flavourful product with specific textural attributes. However, the complexity of its composition (pH, solubilisation of calcium from the colloidal casein proteins, salt concentration, acid production rate, indigenous and added enzymes, residual activity of the enzymes etc.) coupled with the length of time associated with manufacturing which in some cases can be in excess of two years has made it a complicated area of study. The influences of the composition and process contributors are confounded and it is impossible to connect the impact of one particular parameter on cheese making steps and quality attributes. pH has proven to be an important influential factor to influence the extent of effects of other parameters with significant influence on other ruling parameters in milk, curd and cheese. Proteolysis during ripening is the most important physicochemical pathway to define the quality of cheese. One of the major factors governing cheese ripening reactions is the starter bacteria. This study has aimed to characterise the effects of starter bacteria activity on curd formation and resultant cheese textural attributes of the long fermented cheesemilk. By developing a pH-stat system, long fermentations carried out to assess the proteolytic activity of selected starter lactic acid bacteria (LAB) on a milk based medium before rennet addition. It was attempted to assess the degree of hydrolysis of cheesemilk through extended bacterial fermentation, conducted under pH-stat conditions, prior to curd formation. The effects of the bacterial activity on casein proteins during pH-stat long term (PSLT) fermentations were evaluated by assessing proteolysis index from pH4.6 soluble nitrogen as a fraction of total nitrogen (pH4.6SN/TN). The proteolysis of proteins during PSLT was further assessed by doing reverse-phase high performance liquid chromatography (RP-HPLC) on 70%Ethanol soluble (70%EtOHS) and insoluble (70%EtOHI) fractions of pH4.6 soluble fraction of the samples. The effects of PLST fermentation on formation of small-size peptides were assessed by quadrupole time-of-flight mass spectrometry (Q-ToF MS) on the 70%EtOHS fraction. The effect of PLST fermentation on ‘depth of proteolysis’ during cheese ripening were assessed by analysing the quantity of free amino acid (FAA) formed in resultant cheese after 12 months storage at 4°C. The impact of PLST fermentation on gel formation attributes were assessed by doing dynamic law amplitude oscillatory rheometry (DLAOR). The consequent effects on resultant cheese texture were evaluated using texture profile analysis (TPA). The impact of PSLT on microstructure were assessed by confocal laser scanning microscopy (CLSM). The results provided evidence for the adequacy of developed fermentation to conduct PSLT with reproducible results. High correlation between the parameters of the PSLT fermentation system were obtained. The proteolysis index measured from the PSLT fermentations with different durations showed evidences on the significance of LAB proteolytic system on cheese milk prior to curd formation. The proteolysis index for the longest fermentation prior to curd formation was 5% which was comparable to day one cheese proteolysis index, in presence of rennet, in most cheeses varieties. Peptide profiling of the 70%EtOHS and 70%EtOHI sub-fractions of pH4.6S showed significant (p<0.05) effects arising from PSLT fermentations. Analysis of FAA of ripened cheese also showed a significant increase (p<0.05) in the samples with longer PSLT (20 times increase in total free amino acids compared to non-fermented treatment) fermentations. The differences in gelation behaviour of the sample and textural attributes of cheese and microstructure of final cheese were connected to the extent of proteolytic activity of LAB during PSLT fermentations. The hardness of cheese significantly (p<0.05) decreased (up to ~60%) by increasing fermentation duration over the studied timescale

O(N)-Space Spatiotemporal Filter for Reducing Noise in Neuromorphic Vision Sensors

Neuromorphic vision sensors are an emerging technology inspired by how retina processing images. A neuromorphic vision sensor only reports when a pixel value changes rather than continuously outputting the value every frame as is done in an 'ordinary' Active Pixel Sensor (ASP). This move from a continuously sampled system to an asynchronous event driven one effectively allows for much faster sampling rates; it also fundamentally changes the sensor interface. In particular, these sensors are highly sensitive to noise, as any additional event reduces the bandwidth, and thus effectively lowers the sampling rate. In this work we introduce a novel spatiotemporal filter with O(N)O(N) memory complexity for reducing background activity noise in neuromorphic vision sensors. Our design consumes 10× less memory and has 100× reduction in error compared to previous designs. Our filter is also capable of recovering real events and can pass up to 180 percent more real events

Evaluation of severity of work limitation in patients with osteoarthrosis referring to Velayat hospital

Introduction and objectives: Osteoarthritis (OA) is a chronic disease which affected the different aspect of patient’s life. According to the articles it can affect quality of life and physical activity of patients. In this study we investigated the physical activity limitations and factors related to it in patients with OA

Actinomyceten aus vernachlässigten Gebieten, iranischen Böden, ihre Taxonomie und Sekundärmetabolite

Actinobacteria constitute the largest among 30 major phyla of Eubacteria. Actinobacteria are Gram-positive and are well known as producers of bioactive secondary metabolites, which have been utilized in medical, industrial, and agricultural applications. More than 50% of the currently described antibiotics are produced by Actinobacteria. In search of new bioactive compounds, researchers are now having to search neglected or yet undiscovered habitats. In this work, novel Actinobacteria have been isolated from various locations in Iran and neglected environments in Germany. Among those, two strains (M2T and M3) were examined for polyphasic taxonomy. Strain M2T was identified as a novel species within the genus Streptomonospora. Analysis and isolation of compounds from its extract revealed two novel thiopeptide derivatives (litoralimycins A and B). Another study identified strain 86D, isolated from Lavasan/Iran, with moderate activity against Bacillus subtilis DSM 10 and Staphylococcus aureus Newman. The polyphasic findings support that strain 86D represents a novel species in the genus Streptomyces. From the non-Streptomyces strains isolated from the soil of Iran, strain 31sw was selected for polyphasic taxonomy. The chemotaxonomy evaluation and whole-genome sequencing data supported the notion that 31sw belongs to the genus Saccharomonospora. Strain 31sw represents a potential subspecies of species Saccharomonospora xinjiangensis DSM 44391T.Actinobakterien bilden das größte der 30 Hauptphyla der Eubakterien. Actinobakterien sind Gram-positiv und bekannt als Produzenten von bioaktiven Sekundärmetaboliten, die in der Medizin, Industrie und Landwirtschaft eingesetzt werden. Mehr als 50% der derzeit beschriebenen Antibiotika werden von Actinobakterien produziert. Auf der Suche nach neuen bioaktiven Verbindungen durchsuchen Forscher vernachlässigte oder noch unerforschte Lebensräume. In dieser Arbeit wurden neue Actinobakterien von verschiedenen Standorten im Iran und aus vernachlässigten Lebensräumen in Deutschland isoliert. Davon wurden zwei Stämme (M2T und M3) mittels der polyphasische Taxonomie untersucht. Der Stamm M2T wurde als eine neue Spezies innerhalb der Gattung Streptomonospora identifiziert. Die Analyse und Isolierung von Verbindungen aus seinem Extrakt ergab zwei neue Thiopeptidderivate (Litoralimycine A und B). Eine weitere Studie identifizierte den Stamm 86D, isoliert aus einer prober aus Lavasan/Iran, mit moderater Aktivität gegen Bacillus subtilis DSM 10T und Staphylococcus aureus Newman. Die polyphasischen Befunde unterstützen, dass Stamm 86D eine neue Spezies in der Gattung Streptomyces darstellt. Von den Nicht-Streptomyces-Stämmen, die aus dem Boden des Iran isoliert wurden, wurde der Stamm 31sw für die polyphasische Taxonomie ausgewählt. Die chemotaxonomische Auswertung und die Daten der Ganzgenomsequenzierung unterstützten die Annahme, dass 31sw zur Gattung Saccharomonospora gehört. Der Stamm 31sw repräsentiert eine potentielle Unterart der Spezies Saccharomonospora xinjiangensis DSM 44391T

Plug and Play DC-DC Converters for Smart DC Nanogrids with Advanced Control Ancillary Services

This paper gives a general view of the control possibilities for dc-dc converters in dc nanogrids. A widely adopted control method is the droop control, which is able to achieve proportional load sharing among multiple sources and to stabilize the voltage of the dc distribution bus. Based on the droop control, several advanced control functions can be implemented. For example, power-based droop controllers allow dc-dc converters to operate with power flow control or droop control, whether the hosting nanogrid is operating connected to a strong upstream grid or it is operating autonomously (i.e., islanded). Converters can also be equipped with various supporting functions. Functions that are expected to play a crucial role in nanogrids that fully embrace the plug-and-play paradigm are those aiming at the monitoring and tuning of the key performance indices of the control loops. On-line stability monitoring tools respond to this need, by continuously providing estimates of the stability margins of the loops of interest; self- tuning can be eventually achieved on the basis of the obtained estimates. These control solutions can significantly enhance the operation and the plug-and-play feature of dc nanogrids, even with a variable number of hosted converters. Experimental results are reported to show the performance of the control approaches

Analysis of an On-Line Stability Monitoring Approach for DC Microgrid Power Converters

An online approach to evaluate and monitor the stability margins of dc microgrid power converters is presented in this paper. The discussed online stability monitoring technique is based on the Middlebrook's loop-gain measurement technique, adapted to the digitally controlled power converters. In this approach, a perturbation is injected into a specific digital control loop of the converter and after measuring the loop gain, its crossover frequency and phase margin are continuously evaluated and monitored. The complete analytical derivation of the model, as well as detailed design aspects, are reported. In addition, the presence of multiple power converters connected to the same dc bus, all having the stability monitoring unit, is also investigated. An experimental microgrid prototype is implemented and considered to validate the theoretical analysis and simulation results, and to evaluate the effectiveness of the digital implementation of the technique for different control loops. The obtained results confirm the expected performance of the stability monitoring tool in steady-state and transient operating conditions. The proposed method can be extended to generic control loops in power converters operating in dc microgrids

The Effect of Teacher’s Scaffolding and Peers’ Collaborative Dialogue on the Acquisition of English Tenses in the Zone of Proximal Development: A Sociocultural Perspective

This study investigated the extent to which teacher’s scaffolding and peers’ collaborative dialogue could contribute to the acquisition of English tenses in Iranian EFL learners with different levels of grammatical knowledge. To fulfill this objective, 142 college students were selected through convenience sampling to constitute the scaffolding and collaborative groups. After the participants’ initial level of grammatical knowledge was measured by a pre-test, they received their respective treatment and their achievement was measured by a series of immediate post-tests and a final post-test. The results indicated no significant difference between the performances of the two experimental groups. When the collected data were analyzed for high achiever and low achiever subgroups formed based on their interlocutors, no significant differences were observed between high achiever subgroups. But it was found that those low achievers who received assistance from the teacher and those who collaborated with high achievers had significantly better performances than those low achievers who collaborated with low achievers. Therefore, it can be concluded that the knowledge and expertise needed for helping the learners move ahead in their ZPD can be provided in those dyadic configurations in which at least one of the interlocutors exceeds a threshold level of knowledge

The Effect of Teacher’s Scaffolding and Peers’ Collaborative Dialogue on the Acquisition of English Tenses in the Zone of Proximal Development: A Sociocultural Perspective

This study investigated the extent to which teacher’s scaffolding and peers’ collaborative dialogue could contribute to the acquisition of English tenses in Iranian EFL learners with different levels of grammatical knowledge. To fulfill this objective, 142 college students were selected through convenience sampling to constitute the scaffolding and collaborative groups. After the participants’ initial level of grammatical knowledge was measured by a pre-test, they received their respective treatment and their achievement was measured by a series of immediate post-tests and a final post-test. The results indicated no significant difference between the performances of the two experimental groups. When the collected data were analyzed for high achiever and low achiever subgroups formed based on their interlocutors, no significant differences were observed between high achiever subgroups. But it was found that those low achievers who received assistance from the teacher and those who collaborated with high achievers had significantly better performances than those low achievers who collaborated with low achievers. Therefore, it can be concluded that the knowledge and expertise needed for helping the learners move ahead in their ZPD can be provided in those dyadic configurations in which at least one of the interlocutors exceeds a threshold level of knowledge