University of Plymouth

About: University of Plymouth is a education organization based out in Plymouth, Plymouth, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 7301 authors who have published 20396 publications receiving 679758 citations.

Polymorphism in the 5′-End of the Aldose Reductase Gene Is Strongly Associated With the Development of Diabetic Nephropathy in Type I Diabetes

Abstract: Recent studies suggest that the gene encoding aldose reductase (ALR2), the enzyme that converts glucose to sorbitol, may confer susceptibility to microvascular disease. DNA from 275 British Caucasian patients with type I diabetes and 102 normal healthy control patients were typed for a (CA)n dinucleotide repeat polymorphic marker in the 5'-region of the ALR2 gene using polymorase chain reaction (PCR). A highly significant decrease in the frequency of the Z+2 allele was found in patients with nephropathy (nephropathy group) compared with those with no complications after a 20-year duration of diabetes (uncomplicated group) (12.7 vs. 38.2%, respectively, chi2 = 18.6, P < 0.00001); this was accompanied by an increase in the Z-2 allele in the nephropathy group (32.0 vs. 12.7% in the uncomplicated group). The nephropathy group also had a significant decrease in the Z/Z+2 genotype compared with the uncomplicated patients (10.7 vs. 44.7%, chi2 = 16.0, P < 0.0001) and an increased frequency of the Z/Z-2 genotype. There was no significant association with diabetic retinopathy. These results demonstrate that the ALR2 gene may play a role in susceptibility to diabetic nephropathy; individuals with the Z+2 allele are more than seven times less likely to develop diabetic renal disease than those without this marker. This marker may prove valuable in screening for patients with diabetic nephropathy at diagnosis of diabetes.

Active zone scaffolds differentially accumulate Unc13 isoforms to tune Ca2+ channel-vesicle coupling

Abstract: Coupling distances between synaptic vesicles and Ca2+ channels determine the efficacy of neurotransmission. Bohme et al. find that presynaptic scaffold complexes spatiotemporally control Unc13 isoforms to establish two independent release pathways at subsynaptic active zones: Unc13B defines nascent, loosely coupled synapses whereas Unc13A facilitates release at mature synapses by tight coupling between Ca2+ channels and synaptic vesicles.

A heuristic formula for turbulence-induced flocculation of cohesive sediment

Abstract: This paper presents new measurements on the settling velocity of mud flocs in the Lower Sea Scheldt, Belgium, and compares the results with data obtained previously in the Tamar estuary, UK. The data show that the flocs are fairly compact with a fractal dimension of about 2.2, which is indicative for reaction limited aggregation processes, characteristic in dynamic aquatic systems with large tidal flow velocities and high SPM (suspended particulate matter) concentrations. The data also reveal a fairly small dependency of the settling velocity from SPM concentrations, consistently much smaller than earlier data published in literature. Furthermore, a simple explicit formulation is proposed for the settling velocity of cohesive sediment in estuaries and coastal seas. It is derived from an analytical solution of a Lagrangean flocculation model, which accounts for turbulence-induced aggregation and floc break-up. Also the effects of variations in SPM and of a limited residence time of the flocs in the turbulent water column are included. The model has been calibrated against data from settling velocity measurements carried out in the Tamar estuary. Values of the measured settling velocity vary between 0.5 and 5 mm s −1 at SPM-values between 0.05 and 8 g l −1 . Using the tuned coefficients, the model describes the observations satisfactory, with an overall relative standard deviation of 30%. Also, the well-known and observed increase in settling velocity with turbulent shear stress at low stresses and the opposite trend at high stresses is described properly. Next, the model is applied to the new data obtained in the Lower Sea Scheldt estuary, again comparing favourably with overall relative standard deviations of 30–50%. It appeared that the coefficients of the model can be determined from independent measurements, but two of them have to be determined by trial and error, for which a simple procedure is proposed.