The nonperturbative functional renormalization group and its applications

The renormalization group plays an essential role in many areas of physics, both conceptually and as a practical tool to determine the long-distance low-energy properties of many systems on the one hand and on the other hand search for viable ultraviolet completions in fundamental physics. It provides us with a natural framework to study theoretical models where degrees of freedom are correlated over long distances and that may exhibit very distinct behavior on different energy scales. The nonperturbative functional renormalization-group (FRG) approach is a modern implementation of Wilson's RG, which allows one to set up nonperturbative approximation schemes that go beyond the standard perturbative RG approaches. The FRG is based on an exact functional flow equation of a coarse-grained effective action (or Gibbs free energy in the language of statistical mechanics). We review the main approximation schemes that are commonly used to solve this flow equation and discuss applications in equilibrium and out-of-equilibrium statistical physics, quantum many-particle systems, high-energy physics and quantum gravity.Comment: v2) Review article, 93 pages + bibliography, 35 figure

Effect of fibromyalgia on bone mineral density in patients with fibromylagia and rheumatoid arthritis

Objectives: Fibromyalgia (FM) may t cause a decrease in bone mineral density (BMD) because of decreased mobility. The condition is relatively frequent in rheumatoid arthritis (RA) and RA patients with FM have more disability than those without FM. We evaluated the effect of FM on BMD and investigated the effect of FM on BMD in RA patients. Materials and Methods: We included age-matched 56 FM, 52 RA patients, and 37 healthy females as controls. Twenty three of all RA subjects met 1990 ACR FM criteria. Patients using the antiresorptive drugs, those on hormone replacement therapy, patients with thyroid or parathyroid dysfunction were excluded. Self-reported pain and fatigue severity, functional items of FM impact questionnaire were questioned in FM and RA patients. In all subjects, BMD of the lumbar spine and femur neck were determined by dual X-ray absorptiometry, and T-scores were recorded. Results: Self-reported pain and fatigue scores in FM subjects were significantly higher than in RA patients (P00.05). There was a significant negative correlation between self-reported pain score and lumbar spine BMD in FM subjects (r=–0.41, P=0.006). Conclusions: In spite of functional disability, FM does not cause a decrease in BMD. The presence of FM in RA patients does not result in a change in BMD

Hand grip strength in patients with type 2 diabetes mellitus

Conclusion: Hand grip strength and key pinch power values were found to be lower in patients with T2DM than in age-matched control subjects. Hands, as well as feet, are also affected by diabetes and physicians should be aware of this. (c) 2005 Elsevier Ireland Ltd. All rights reserved

Global and national harmonization and standardization of clinical laboratory testings: The example of HbA1c

The equivalent or harmonized test results between different clinical laboratories and methods are the main requirements in order to achieve the quality health care. In this context, global standardization studies have been carried out worldwide. The major goal of standardization is the harmonization of patient test results. Standardization is established according to metrological principles. Even if the reference system for analyte is established, the harmonization still may not be achieved. The interlaboratory comparison studies provide evidence-based knowledge about harmonized test results. This way is also useful for the harmonization of analytes which are not well defined and for which reference procedures are not available. The aim of our study is to open the discussion of the importance of the national harmonization system for the effective healthcare services in the context of the HbA(1c) interlaboratory comparison study performed. The studies and improvements on the global standardization and harmonization of clinical laboratory test results were reviewed; the global standardization of HbA(1c) study was summarized, and the results of the HbA(1c) interlaboratory comparison study performed in Turkey was discussed as an example for the national standardization and harmonization of a laboratory test. In our example study, the coefficients of variation between the laboratories for both normal and pathologic levels were found higher than the target value, while the bias values were found in the acceptable levels. Although our study provides some reliable findings, more interlaboratory comparison programs should be carried out, and the national harmonization system should be established for every relevant analyte

Effects of Leptin on Intestinal Ischemia–Reperfusion Injury

Many clinical conditions such as shock, sepsis, mesenteric thrombosis, necrotizing enterocolitis, and bowel transplantation can cause intestinal ischemia–reperfusion (IR) injury. This study was designed to determine the effects of leptin on intestinal IR injury. Thirty rats were divided into three groups, each containing ten rats: group A (IR group), group B (treatment group), and group C (sham group). After 1 h of intestinal ischemia, the clamp was removed in order to perform reperfusion. In group B, 100 mg/kg leptin was administered subcutaneously 30 min before reperfusion. In groups A and C, 0.1 ml physiologic saline was injected. In group A, serum and tissue nitric oxide (NO) levels were significantly decreased, and malondialdehyde levels were significantly increased compared to sham group (p < 0.05). Histopathologic injury was significantly lower in sham group compared to group A. In group B, serum and tissue malondialdehyde levels were significantly decreased (p < 0.05), but serum and tissue NO levels were significantly increased compared to group A (p < 0.05). Histopathologic injury was significantly lower in group B compared to group A (p < 0.05). The results of the present study demonstrated that leptin decreases intestinal IR injury by increasing NO production, rearranging mucosal blood flow, and inhibiting polymorphonuclear leukocyte infiltration