Insulin detemir offers improved glycemic control compared with NPH insulin in people with type 1 diabetes - A randomized clinical trial

OBJECTIVE—Insulin detemir is a soluble long-acting basal insulin analog designed to overcome the limitations of conventional basal insulin formulations. Accordingly, insulin detemir has been compared with NPH insulin with respect to glycemic control (HbA1c, prebreakfast glucose levels and variability, and hypoglycemia) and timing of administration. RESEARCH DESIGN AND METHODS—People with type 1 diabetes (n = 408) were randomized in an open-label, parallel-group trial of 16-week treatment duration using either insulin detemir or NPH insulin. Insulin detemir was administered twice daily using two different regimens, either before breakfast and at bedtime (IDetmorn+bed) or at a 12-h interval (IDet12h). NPH insulin was administered before breakfast and at bedtime. Mealtime insulin was given as the rapid-acting insulin analog insulin aspart. RESULTS—With both insulin detemir groups, clinic fasting plasma glucose was lower than with NPH insulin (IDet12h vs. NPH, −1.5 mmol/l [95% CI −2.51 to −0.48], P = 0.004; IDetmorn+bed vs. NPH, −2.3 mmol/l (−3.32 to −1.29), P < 0.001), as was self-measured prebreakfast plasma glucose (P = 0.006 and P = 0.004, respectively). The risk of minor hypoglycemia was lower in both insulin detemir groups (25%, P = 0.046; 32%, P = 0.002; respectively) compared with NPH insulin in the last 12 weeks of treatment, this being mainly attributable to a 53% reduction in nocturnal hypoglycemia in the IDetmorn+bed group (P < 0.001). Although HbA1c for each insulin detemir group was not different from the NPH group, HbA1c for the pooled insulin detemir groups was significantly lower than for the NPH group (mean difference −0.18% [−0.34 to −0.02], P = 0.027). Within-person between-day variation in self-measured prebreakfast plasma glucose was lower for both detemir groups (both P < 0.001). The NPH group gained weight during the study, but there was no change in weight in either of the insulin detemir groups (IDet12h vs. NPH, −0.8 kg [−1.44 to −0.24], P = 0.006; IDetmorn+bed vs. NPH, −0.6 kg [−1.23 to −0.03], P = 0.040). CONCLUSIONS—Overall glycemic control with insulin detemir was improved compared with NPH insulin. The data provide a basis for tailoring the timing of administration of insulin detemir to the individual person’s needs

Laminar Natural Convection Heat Transfer of Water-Based Nanofluids in Square Enclosure Containing Heater

Bu çalışmada, dik kenarlardan biri soğutulurken diğeri ısıtılan, alt ve üst kenarları yalıtılmış, bir kare kutu ele alınmıştır. Kapalı kare kutunun içi, tek faz olarak ele alınan su bazlı nanoakışkan ile doludur. Nanopartikül olarak Cu, Al2O3 ve TiO2 seçilmiştir. Çalışmada katı partiküllerin hacim fraksiyonunun 0.0 ≤ ߮ ≤ 0.2 aralığındaki değerleri göz önüne alınmıştır. Kare kutunun, sol dik kenardaki ısıtıcı konumu, içindeki su bazlı nanoakışkan çeşidi ve katı hacim fraksiyonu değiştirilerek, sürekli rejimde laminer doğal taşınım ile meydana gelen ısı geçişi sayısal olarak incelenmiştir. Sol dik kenarda iki farklı parçalı ısıtıcı kullanımının ısı geçişine ve hava sirkülasyonuna etkisi araştırılmıştır. Bu esnada sisteme giren ısı sabit tutulmuş, ısıtıcı ve soğuk duvar izotermal kabul edilmiştir. Yönetici denklemler; süreklilik, yoğunluk farkı için Boussinesq yaklaşımının kullanıldığı Navier-Stokes denklemleri ve enerji denklemi Fluent® yazılımı aracılığıyla çözülmüştür. Çözümde SIMPLE algoritması ve taşınım terimlerinin ayrıklaştırılmasında ikinci mertebeden ayrıklaştırma seçeneği kullanılmıştır. Rayleigh sayısı 10 3 − 5 × 10 8 arasında değiştirilmiş, sürekli rejimde ısıtıcıdan ortama geçen ısının hesabının bir ölçüsü olarak soğuk duvar yüzeyi üzerinden ortalama Nusselt sayısı hesaplanmıştır. Bu parametrik çalışma sonucunda Rayleigh sayısı, ısıtıcıların konumu, seçilen su bazlı nanoakışkan çeşidi ve katı partiküllerin hacim fraksiyonu değiştirilerek parametrik analizleri yapılmış, ısıtıcıların soğutulması açısından elde edilen sayısal değerler, akım çizgileri ve eş sıcaklık eğrileri ile verilmiştir.In this study, a square enclosure is analyzed while one of the vertical side is cooling and the left vertical side is heating. The top and the bottom sides are isolated. The inside of the enclosure is filled with a single-phase, water-based nanofluid. Cu, Al2O3 and TiO2 are selected as of nanoparticles. The volume fraction of solid particles is in the range 0.0 ≤ ߮ ≤ 0.2 . Steady laminar natural convection heat transfer in the enclosure, while changing the type and the volume fraction of nanoparticle and the position of heater on the left vertical side, is investigated numerically. The effect of using two discrete heaters on the heat transfer and flow circulation is investigated. The total heat strength of the discrete heaters, which are the only source of heat to the system, is kept constant. The heater and cold side are isothermal. The governing equations; continuity equation, Navier-Stokes equations and the energy equation along with Boussinesq approximation are solved using the Fluent®software. The SIMPLE algorithm and second order upwind scheme was used in the discretization of transport terms. Rayleigh number is chosen as 10 3 − 5 × 10 8 and as a measure of the steady state convection heat transfer, the average Nusselt number over the cold surface is calculated. In this parametric study, the position of heater, the type of water-based nanofluid and the volume fraction of solid particles are changed and parametric analyses are conducted. As a result, obtained numerical values and the contours of temperature and stream function for cooling of heaters are given