Spin Echo, Fidelity, and the Quantum Critical Fan in TmVO_{4}.

Using spin-echo nuclear magnetic resonance in the model transverse field Ising system TmVO_{4}, we show that low frequency quantum fluctuations at the quantum critical point have a very different effect on ^{51}V nuclear spins than classical low-frequency noise or fluctuations that arise at a finite temperature critical point. Spin echoes filter out the low-frequency classical noise but not the quantum fluctuations. This allows us to directly visualize the quantum critical fan and demonstrate the persistence of quantum fluctuations at the critical coupling strength in TmVO_{4} to high temperatures in an experiment that remains transparent to finite temperature classical phase transitions. These results show that while dynamical decoupling schemes can be quite effective in eliminating classical noise in a qubit, a quantum critical environment may lead to rapid entanglement and decoherence.

Quality assurance of medicines supplied to low-income and middle-income countries: poor products in shiny boxes?

OBJECTIVE: In today's context of globalisation of pharmaceutical production and distribution, international and national procurement agencies play a de facto key role in defining the quality of medicines available in sub-Saharan Africa. We evaluated the compliance of a sample of pharmaceutical distributors active in sub-Saharan Africa with the standards of the WHO guideline 'Model Quality Assurance System (WHO MQAS) for procurement agencies', and we investigated factors favouring or hindering the adequate implementation of the guideline. METHODS: We used mixed-methods methodology to analyse quantitative and qualitative data. The quantitative study consisted of a retrospective secondary analysis of data collected by QUAMED (Quality Medicines for all), a partnership that pleads for universal access to quality-assured medicines. The qualitative survey consisted of formal and informal interviews with key informants. We adopted an embedded multiple-case study design. FINDINGS: Our analysis suggests that international distributors based in Europe perform, on average, better than sub-Saharan African distributors. However, some weaknesses are ubiquitous and concern critical processes, such as the initial selection of the products and the ongoing reassessment of their quality. This is due to several different factors: weak regulatory oversight, insufficient human/financial resources, weak negotiating power, limited judicial autonomy and/or lack of institutional commitment to quality. CONCLUSIONS: Our findings suggest that pharmaceutical distributors active in sub-Saharan Africa generally do not apply stringent criteria for selecting products and suppliers. Therefore, product quality is not consistently assured but depends on the requirements of purchasers. While long-term solutions are awaited, the WHO MQAS guideline should be used as an evaluation and training tool to upgrade current standards.

Comparison of two insulin protocols for diabetic dogs undergoing cataract surgery.

Objective To evaluate the effectiveness of two insulin doses to maintain an acceptable range of blood glucose concentrations (70-200 mg dL-1) in the peri-operative period in diabetic dogs. Animals Twenty-four diabetic dogs with a median weight of 20.6 kg and a median age of 8 years old. Methods The dogs were randomly assigned to receive either 25 or 100% of their normal insulin dose subcutaneously on the morning of surgery. The anesthetic and feeding protocols were standardized. On the day before surgery, venous blood was collected for measurement of ß-hydroxybutyrate, cholesterol, glucose, glycosylated hemoglobin, hematocrit, total plasma protein and urea nitrogen. On the day of surgery, blood glucose concentrations were measured prior to anesthesia, prior to the start of surgery, 1 and 2 hours after beginning of surgery, 1 hour after extubation, at 16 : 00 hours and at 20 : 00 hours. ß-hydroxybutyrate concentrations were measured at 20 : 00 hours that day. At 08 : 00 hours the following day, ß-hydroxybutyrate and glucose concentrations were measured. The significance of differences between groups was tested with Wilcoxon's two-tailed rank-sum test, Chi-square test and Fisher's exact test. Results There were no differences in insulin treatments, clinical signs, concurrent diseases and most clinicopathological parameters between the two groups of dogs at entry to the study. The 25% dose group had blood glucose values of 296 (102-601) mg dL-1 at 16 : 00 hours and 429 (97-595) mg dL-1 at 20 : 00 hours on the day of surgery. The 100% insulin dose group had lower corresponding values of 130 (55-375) mg dL-1 (p = 0.04) and 185 (51-440) mg dL-1 (p = 0.004). No other differences (p < 0.05) were detected between the two groups. Conclusions The administration of a full dose of insulin is only marginally advantageous for reducing glucose to normal (70-120 mg dL-1) after anesthesia but neither dose consistently induced glycemic values in an acceptable range (70-200 mg dL-1) or normoketonemia. Clinical relevance Blood glucose should be measured immediately before anesthesia and periodically throughout the peri-operative period in all diabetic dogs because presurgical subcutaneous administration of 25 or 100% of the normal insulin dose resulted in unpredictable blood glucose concentrations.

Effect of topical administration of epidermal growth factor on healing of corneal epithelial defects in horses.

UNLABELLED: OBJECTIVE-To characterize healing of corneal epithelial defects in horses and to evaluate the ability of epidermal growth factor (EGF) to modulate rate of corneal epithelial healing in horses. SAMPLE POPULATION: 20 eyes in 12 adult horses. PROCEDURE: Corneal epithelial wounds were created by mechanically debriding the limbus. Corneal healing was recorded for 3 treatment groups: 50 microg of EGF/ml (n = 5 eyes), 5 microg of EGF/ml (7), and PBS solution (8). Corneal healing was recorded once daily after instillation of fluorescein stain by use of photography and calculating the area of the wound, using imaging software. RESULTS: After corneal debridement, re-epithelialization was rapid and progressed in a linear fashion for the first 5 to 7 days after surgery in all groups. After that period, rates of healing decreased. A profound increase in the degree of inflammation, neovascularization, melanosis, and scarring was observed in eyes treated with the high dose of EGF (50 microg/ml), but there was not a statistical difference in mean healing time or in mean decrease in radius during the linear phase between the control and either EGF treatment groups. However, for all 8 horses in which both eyes were debrided, the first eye healed significantly faster than the second eye, regardless of treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Beneficial effects of topical administration of a high dose of EGF for acceleration of healing of corneal defects in eyes of horses are outweighed by the intensity of the associated inflammatory response.