Widespread CO2-rich cordierite in the UHT Bakhuis granulite belt, Surinam

The Bakhuis Granulite Belt, approx. 30 x 100 km, transects the large Paleoproterozoic greenstone belt along the north-eastern coast of South America. Part of the Granulite belt witnessed typical Ultrahigh-Temperature Metamorphism (UHTM). A metapelite area in the NE of the belt shows assemblages characteristic of UHTM: aluminous (up to 10 wt.%) orthopyroxene + sillimanite +/- sapphirine. Leucosomes commonly show mesoperthite or K-rich antiperthite. Ternary feldspar thermometry indicates a peak temperature of 1000-1050°C and pressure is estimated to have been around 9 kbar. Metapelites elsewhere in the belt lack mineral assemblages characteristic of UHTM. However, feldspar thermometry for these metapelites as well as for mesoperthite granulites indicates that peak temperatures were 900°C or higher throughout the belt and locally reached 1000-1050°C. It is, therefore, concluded that the other parts of the belt also witnessed UHTM, despite their lack of typical UHTM assemblages. Study of peak assemblages in metapelites in these parts is hampered by varying, but usually considerable retrograde metamorphism. The main mafic mineral in metapelites is coarse Mg-rich cordierite, accompanied by coarse sillimanite. Widespread occurrence of cordierite + sillimanite in metapelites is unusual for UHTM, the more so as UHTM assemblages are commonly formed at the expense of cordierite-bearing assemblages. In a small part of the metapelites cordierite is accompanied by coarse aluminous (up to 9 wt.%) orthopyroxene. Associated cordierite and orthopyroxene appear to have formed in equilibrium with each other. Only the presence of aluminous orthopyroxene (as well as the presence of mesoperthite) is typical for UHTM, but is limited to a small part of the metapelites. Peak P-T conditions for the cordierite-bearing part of the belt are estimated to have been similar to those in the NE area with its characteristic UHTM assemblages. Primary and secondary fluid inclusions in UHT quartz blebs in orthopyroxene consist of pure CO2 and have a high density. Raman spectroscopy indicated a considerable CO2 content in cordierite. Estimated from their birefringence, the CO2 content of most cordierites is in the range of 1-2 wt.% CO2. This corresponds to a substantial filling of the cordierite channels with CO2 and for the higher levels possibly near-saturation with CO2 according to the model of Harley and Thompson for the maximum level of CO2 in cordierite. Thermodynamic data for CO2-rich cordierite are poorly known. However, a high level of CO2 in cordierite has been considered to lead to a substantial expansion of its stability field, also into the field of UHTM, at T > 900°C. This is, therefore, assumed to be the explanation for the unusual, widespread occurrence of cordierite in the UHTM belt. A small part of the metapelite samples shows cordierite of a high birefringence, twice that of quartz. SIMS analysis of such cordierite showed 3.0 wt.% CO2, the highest level known from nature. The level is far too high to have formed at UHTM conditions according to the model of Harley and Thompson and would be possible only at conditions such as 700°C and 10 kbar. It is assumed that locally the CO2 level of cordierite changed after UHTM, by taking up additional CO2. Secondary fluid CO2 inclusions in UHT quartz have a higher density than the primary inclusions, indicating a near-isobaric cooling path down to 700-750°C. In these conditions cordierite probably could steadily re-equilibrate at decreasing temperature while taking up more and more CO2, up to 3 wt.% around 700°C. The heat source for the UHTM in the Bakhuis Granulite belt is considered to be asthenospheric upwelling or mafic underplating, but mafic magmatism of identical age to the UHTM has not yet been found. One mafic intrusion was found to be around 20 Ma older than the UHTM, whereas in the SW of the belt numerous mafic intrusions formed around 70 Ma after UHTM

Effect of device-guided breathing exercises on blood pressure in hypertensive patients with type 2 diabetes mellitus:A randomized controlled trial

Objective In patients with type 2 diabetes mellitus (DM2), it is hard to reach treatment objectives for blood pressure (BP) with classical treatment options. Recently, reducing breathing frequency has been advocated as a method to reduce BP. We examined if an electronic device such as Resperate, by reducing breathing frequency, would lead to BP reduction in a population of patients with DM2 and hypertension. Our secondary objective was to study the effect of this device on quality of life (QOL). Methods A randomized, single-blind, controlled trial was conducted over a period of 8 weeks to evaluate the effect of this therapy on BP and QOL. The control group listened to music and used no other therapeutic device. BP and QOL changes were studied in 30 patients with DM2 and hypertension. Results There was no significant difference in change in BP between groups; -7.5 [95% confidence interval (CI) -12.7, -2.3]/-1.0 (95% CI -5.5, 3.6) mmHg in the intervention group and -12.2 (95% CI -17.4, -7.0)/-5.5 (95% CI -9.7, -1.4) mmHg in the control group. Whether or not the target breathing frequency of 10 breaths/min was reached did not affect BP. There were no significant changes in QOL. Conclusions The effects of Resperate on BP and QOL were not significantly different from those found in the control group. Furthermore, 40% of patients did not reach the target breathing frequency, making this device less suitable for clinical practice in patients with DM2

Compartment syndrome and popliteal vascular injury complicating unicompartmental knee arthroplasty

Popliteal vascular injury and the compartment syndrome of the leg are rare but important complications of knee arthroplasties. Early diagnosis and treatment are of paramount importance in preventing the devastating complications of these conditions. To our knowledge, these complications have not been reported previously after unicompartmental knee arthroplasty in the literature. Low level of suspicion may delay the diagnosis, as popliteal vascular injury and compartment syndrome are not well recognized as possible complications of unicompartmental knee arthroplasty

Health-Related Quality of Life, Treatment Satisfaction, and Costs Associated With Intraperitoneal Versus Subcutaneous Insulin Administration in Type 1 Diabetes: A randomized controlled trial

OBJECTIVE - To investigate the effects of continuous intraperitoneal insulin infusion (CIPII) compared with subcutaneous insulin on health-related quality of life (HRQOL) and treatment satisfaction, and to perform a cost analysis in type 1 diabetes. RESEARCH DESIGN AND METHODS - We used an open-label, prospective, crossover, randomized, 16-month study (N = 24). HRQOL and patient satisfaction were assessed with questionnaires (the 36-item short-form health survey [SF-36], the World Health Organization-Five Well-Being Index [WHO-5], and the Diabetes Treatment Satisfaction Questionnaire [DTSQ]). Direct costs of CIPII and continuous subcutaneous insulin infusion (CSII) were compared. RESULTS - Questionnaire scores were higher with CIPII than with subcutaneous therapy. Yearly direct pump- and procedure-associated costs for CIPII were estimated at 10,910 compared with 4,810 for CSII. C CONCLUSIONS - Apart from improving glycemic control, CIPII improved HRQOL and treatment satisfaction compared with subcutaneous insulin. Direct pump- and procedure-associated costs are considerably higher for CIPII, however