Deflection of unbonded partially prestressed concrete continuous beams

Continuous beams are preferred to simply supported beams because of economy, fewer expansion / contraction joints and possible benefits from moment redistribution. In the design of unbonded partially prestressed concrete (UPPC) continuous beams, it is necessary to estimate their deflections under service loads in order to satisfy the requirements of serviceability limit state. A method is developed to convert the cross sectional area of unbonded prestressed tendons to the equivalent cross sectional area of non-prestressed steel. Then the moment of inertia of cracked section as well as Branson’s effective moment of inertia in a UPPC continuous beam can be easily determined. The computed deflections are compared with some available experimental results, including beams with external unbonded steel tendons and those with external unbonded aramid fibre reinforced polymer tendons. The proposed method gives satisfactory predictions of deflection till the yielding of non-prestressed steel. Another equation for moment of inertia of cracked section, which was originally suggested by the PCI design handbook for bonded partially prestressed concrete beams, is also evaluated in the study. In most cases the PCI equation can also give satisfactory results but in some cases its discrepancy of deflections is larger than that of the proposed method. Compared with the method recommended in the current Chinese Code, the proposed method is applicable not only to members with the conventional high-strength steel prestressing tendons, but also to those with tendons made of other materials such as fibre-reinforced polymer

Human epidermal growth factor enhances healing of diabetic foot ulcers

OBJECTIVE - To study the healing effect of recombinant human epidermal growth factor (hEGF) on diabetic foot ulcers. RESEARCH DESIGN AND METHODS - A total of 127 consecutive patients were screened and 61 diabetic subjects were recruited into this double-blind randomized controlled study. Predetermined criteria were used for diagnosis and classification of the diabetic wound. The patients were randomized into three groups. All patients attended our Diabetes Ambulatory Care Center every other week for joint consultation with the diabetologist and the podiatrist. Group 1 (control) was treated with Actovegin 5\% cream (Actovegin), group 2 with Actovegin plus 0.02\% (wt/wt) hEGF, and group 3 with Actovegin plus 0.04\% (wt/wt) hEGF. The study end point was the complete closure of the wound. Failure to heal was arbitrarily defined as incomplete healing after 12 weeks. RESULTS - Final data were obtained from 61 patients randomly assigned into three groups. The mean ages of the patients, wound sizes, wound duration, metabolic measurements, and comorbidities were comparable within groups, except that group 3 had more female patients. Mean follow-up for the patients was 24 weeks. Data were cutoff at 12 weeks, and results were analyzed by intention to treat. After 12 weeks, in group 1 (control) eight patients had complete healing, two patients underwent toe amputation, and nine had nonhealing ulcers. In group 2 (0.02\% [wt/wt] hEGF) 12 patients experienced wound healing, 2 had toe amputations and 7, had nonhealing ulcers. Some 20 of 21 patients in group 3 (0.04\% [wt/wt] hEGF) showed complete wound healing. Healing rates were 42.10, 57.14, and 95\% for the control 0.02\%, (wt/wt) hEGF, and 0.04\% (wt/wt) hEGF groups, respectively. Kaplan-Meier survival analysis suggested that application of cream with 0.04\% (wt/wt) hEGF caused more ulcers to heal by 12 weeks and increased the rate of healing compared with the other treatments (log-rank test, P = 0.0003). CONCLUSIONS - Our data support the contention that application of hEGF-containing cream, in addition to good foot care from a multidisciplinary team, significantly enhances diabetic foot ulcer wound healing and reduces the healing time

Preconception sleep quality moderates the association between preconception hair cortisol levels and mental health in pregnant women

10.1016/j.jad.2023.04.129J Affect Disord334187-19