Partitioning of starter bacteria and added exogenous enzyme activities between curd and whey during Cheddar cheese manufacture

peer-reviewedPartitioning of starter bacteria and enzyme activities was investigated at different stages of Cheddar cheese manufacture using three exogenous commercial enzyme preparations added to milk or at salting. The enzyme preparations used were: Accelase AM317, Accelase AHC50, Accelerzyme CPG. Flow cytometric analysis indicated that AHC50 or AM317 consisted of permeabilised or dead cells and contained a range of enzyme activities. The CPG preparation contained only carboxypeptidase activity. Approximately 90% of starter bacteria cells partitioned with the curd at whey drainage. However, key enzyme activities partitioned with the bulk whey in the range of 22%–90%. An increased level of enzyme partitioning with the curd was observed for AHC50 which was added at salting, indicating that the mode of addition influenced partitioning. These findings suggest that further scope exists to optimise both bacterial and exogenous enzyme incorporation into cheese curd to accelerate ripening.Department of Agriculture, Food and the Marin

Cyclic AMP-vepenvent protein kinase phosphorylates residues in the C-terminal domain of the cardiac L-type calcium channel α1 subunit

AbstractThe molecular basis of the regulation of cardiac L-type calcium channel activity by cAMP-vepenvent protein kinase (cA-PK) remains unclear. Direct cA-PK-vepenvent phosphorylation of the bovine ventricular α1 subunit in vitro has been vemonstrated in microsomal membranes, vetergent extracts and partially purified (+)-[3H]PN 200-100 receptor preparations. Two 32P-labelled phosphopeptives, herived from cyanogen bromive cleavage, of 4.7 and 9.5 kDa were immunoprecipitated specifically by site-directed antibodies against the rabbit cardiac α1 subunit amino acid sequences 1602–1616 and 1681–1694, respectively, consistent with phosphorylation at the cA-PK consensus sites at Ser1627 and Ser1700. No phosphopeptive products consistent with phosphorylation at three other C-terminal cA-PK consensus phosphorylation sites (Ser1575, Ser1848 and Ser1928) were iventified using similar procedures suggesting that these sites are poor substrates for this kinase. Ser1627 and Ser1700 may represent sites of cA-PK phosphorylation involved in the physiological regulation of cardiac L-type calcium channel function

Machine learning a fixed point action for SU(3) gauge theory with a gauge equivariant convolutional neural network

Fixed point lattice actions are designed to have continuum classical properties unaffected by discretization effects and reduced lattice artifacts at the quantum level. They provide a possible way to extract continuum physics with coarser lattices, thereby allowing to circumvent problems with critical slowing down and topological freezing toward the continuum limit. A crucial ingredient for practical applications is to find an accurate and compact parametrization of a fixed point action, since many of its properties are only implicitly defined. Here we use machine learning methods to revisit the question of how to parametrize fixed point actions. In particular, we obtain a fixed point action for four-dimensional SU(3) gauge theory using convolutional neural networks with exact gauge invariance. The large operator space allows us to find superior parametrizations compared to previous studies, a necessary first step for future Monte Carlo simulations.Comment: 22 pages, 15 figures, 6 table

Fixed point actions from convolutional neural networks

Lattice gauge-equivariant convolutional neural networks (L-CNNs) can be used to form arbitrarily shaped Wilson loops and can approximate any gauge-covariant or gauge-invariant function on the lattice. Here we use L-CNNs to describe fixed point (FP) actions which are based on renormalization group transformations. FP actions are classically perfect, i.e., they have no lattice artifacts on classical gauge-field configurations satisfying the equations of motion, and therefore possess scale invariant instanton solutions. FP actions are tree-level Symanzik-improved to all orders in the lattice spacing and can produce physical predictions with very small lattice artifacts even on coarse lattices. We find that L-CNNs are much more accurate at parametrizing the FP action compared to older approaches. They may therefore provide a way to circumvent critical slowing down and topological freezing towards the continuum limit.Comment: 9 pages, 5 figures; Proceedings of the 40th International Symposium on Lattice Field Theory (Lattice 2023

Anatomical and molecular properties of long descending propriospinal neurons in mice

Long descending propriospinal neurons (LDPNs) are interneurons that form direct connections between cervical and lumbar spinal circuits. LDPNs are involved in interlimb coordination and are important mediators of functional recovery after spinal cord injury (SCI). Much of what we know about LDPNs comes from a range of species, however, the increased use of transgenic mouse lines to better define neuronal populations calls for a more complete characterisation of LDPNs in mice. In this study, we examined the cell body location, inhibitory neurotransmitter phenotype, developmental provenance, morphology and synaptic inputs of mouse LDPNs throughout the cervical and upper thoracic spinal cord. LDPNs were retrogradely labelled from the lumbar spinal cord to map cell body locations throughout the cervical and upper thoracic segments. Ipsilateral LDPNs were distributed throughout the dorsal, intermediate and ventral grey matter as well as the lateral spinal nucleus and lateral cervical nucleus. In contrast, contralateral LDPNs were more densely concentrated in the ventromedial grey matter. Retrograde labelling in GlyT2GFP and GAD67GFP mice showed the majority of inhibitory LDPNs project either ipsilaterally or adjacent to the midline. Additionally, we used several transgenic mouse lines to define the developmental provenance of LDPNs and found that V2b positive neurons form a subset of ipsilaterally projecting LDPNs. Finally, a population of Neurobiotin (NB) labelled LDPNs were assessed in detail to examine morphology and plot the spatial distribution of contacts from a variety of neurochemically distinct axon terminals. These results provide important baseline data in mice for future work on their role in locomotion and recovery from SCI

Contextual advantages and certification for maximum confidence discrimination

One of the most fundamental results in quantum information theory is that no measurement can perfectly discriminate between non-orthogonal quantum states. In this work, we investigate quantum advantages for discrimination tasks over noncontextual theories by considering a maximum confidence measurement that unifies different strategies of quantum state discrimination, including minimum-error and unambiguous discrimination. We first show that maximum confidence discrimination, as well as unambiguous discrimination, contains contextual advantages. We then consider a semi-device independent scenario of certifying maximum confidence measurement. The scenario naturally contains undetected events, making it a natural setting to explore maximum confidence measurements. We show that the certified maximum confidence in quantum theory also contains contextual advantages. Our results establish how the advantages of quantum theory over a classical model may appear in a realistic scenario of a discrimination task

Product Distribution in the Low Temperature Conventional Pyrolysis of Nigerian Corn Stalks.

In view of the global energy crises and the ongoing renewable energy studies, clear understanding of the product distribution in the pyrolysis of lignocellulose from different corn plant components is required. Unextracted lignocellulose from the dry corn stalks was pyrolysed at 200oC and 250oC for 30 minutes, 60 minutes, 90 minutes and 120 minutes, respectively in an in house reactor. Liquid (bio-oil), gaseous and solid (bio-char) products were obtained. Their volumes and masses were determined. The volumes of the liquid and gaseous products produced increased with retention time and temperature while the masses of the solid products decreased with retention time and temperature. The pyrolysed corn stalks produced 17.93% bio-oil, 43.33% bio-char and 38.74% gases. The reaction order and rate constants were determined. The reaction was found to be first order. The bio-oil compounds that were detected by GCMS were identified from the MS library and characterized into: acids, ester, alcohol, phenol, alkane, multicomponent compounds and miscellaneous oxygenates. The bio-oils samples obtained were shown to be comparable with those produced by other processes