An atomistic picture of the regeneration process in dye sensitized solar cells

A highly efficient mechanism for the regeneration of the cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II) sensitizing dye (N3) by I^- in acetonitrile has been identified by using molecular dynamics simulation based on density functional theory. Barrier–free complex formation of the oxidized dye with both I^- and , and facile dissociation of and from the reduced dye are key steps in this process. In situ vibrational spectroscopy confirms the reversible binding of I₂ to the thiocyanate group. Additionally, simulations of the electrolyte near the interface suggest that acetonitrile is able to cover the (101) surface of anatase with a passivating layer that inhibits direct contact of the redox mediator with the oxide, and that the solvent structure specifically enhances the concentration of I^- at a distance which further favors rapid dye regeneration.     

Interleukin-10 in Preovulatory Follicular Fluid of Patients Undergoing In-Vitro Fertilization and Embryo Transfer

PROBLEM: The present study aimed at investigating the presence of Interleukin-10 (IL-10) in preovulatory follicular fluid (FF) and its possible correlation with 17-β-estradiol (E₂) and progesterone (P) levels, and treatment outcome in patients undergoing in-vitro fertilization-embryo transfer (IVF-ET). METHODS: Twenty consecutive patients with tubal factor infertility who underwent oocyte retrieval for IVF-ET were assayed for pooled, preovulatory FF levels of IL-10, E₂, and P. RESULTS: The mean FF levels of IL-10, E₂, and P were 78.7 ± 104.7 pg/ml, 2,787.0 ± 726.1 pg/ml, and 1.5 ± 0.8 ng/ml, respectively. No correlation was found between preovulatory FF concentration of IL-10, E₂, oocyte number, oocyte fertilization rate, embryo quality, and pregnancy rate. The levels of IL-10 were found to be negatively correlated with P concentration, although not significantly (P = 0.057). CONCLUSION: Interleukin-10 exists in the preovulatory FF. Further investigations are needed to determine the role of IL-10 in the folliculogenesis.     

Improvements to a method for determining leg length following total hip arthroplasty

Abstract

Discrepancy in leg length does frequently occur as a side effect of total hip arthroplasty and may lead to reduced patient satisfaction as well as injury in the sequalae. It is consequently important to reduce leg length discrepancy where-ever technically possible. This may be achieved by recording precise intraoperative measurements and using different sized implanted components. The aim of the given study was to improve the accuracy of a previously validated optic measurement system (OMS) to reduce leg length discrepancy. This pre-existing OMS was first trialled and based on these preliminary findings developed further. Using this improved system, measurements were taken in models and cadavers. Inter observer reliability of the improved OMS was assessed. The system is introduced in the given technical feasibility study. Its accuracy was greater in the model setup (swivel joint: 772.7?±?1.5?mm; ball joint: 770.0?±?3.7?mm; reference: 772?mm) compared to the trial using cadaveric tissues (588.8?±?5.7?mm; reference: 586?mm). Results of two examiners were similar. The third one measured significantly shorter values (p=.011). The results of the measurements with the OMS indicate that a significant increase in accuracy (p?=?2.076×¹⁰?⁶) has been achieved compared to the previously reported system, however, a further improvement to measurement accuracy is necessary for this to be applied clinically.     

The Presence of Antithyroid Antibodies in Euthyroid Patients With Unexplained Infertility and Tubal Obstruction

PROBLEM: The presence of antithyroid antibodies in euthyroid patients with unexplained infertility and tubal obstruction. METHOD: The presence of antithyroid autoantibodies (microsomal and thyroglobulin) was measured in 40 patients with unexplained infertility, and 40 patients with tubal obstruction infertility, and compared to 40 healthy nulligravidae. RESULTS: Eight patients (20%) in the unexplained infertility study group, seven (17.5%) in the tubal obstruction group and two (5%) in the healthy nulligravida group, were positive for antithyroid autoantibodies: five (12.5%) were positive for antimicrosomal antibodies, two (5%) were positive for antithyroglobulin antibodies, and one patient (2.5%) was positive for both. The tubal obstruction group comprised seven (17.5%) patients positive for antithyroid autoantibodies: four (10%) for antimicrosomal antibodies, two (5%) for antithyroglobulin antibodies, and one patient (2.5%) was positive for both. In the healthy nulligravidae group only two patients (5%) were positive for antithyroid antibodies: one for antimicrosomal and one for antithyroglobulin. No significant differences were found in the presence of antithyroid antibodies between patients with unexplained infertility and those with tubal obstruction infertility. Both groups differed significantly from the healthy controls with regard to the presence of antithyroid antibodies (P < 0.05). CONCLUSION: Subclinical presence of antithyroid autoantibodies is characteristic of both unexplained and mechanical infertility, as opposed to healthy controls. Further investigation of larger groups is needed to determine the prevalence of antithyroid antibodies in the unique population of infertile women.     

The inhibition of matrix metalloproteinase activity in chronic wounds by a polyacrylate superabsorber

Excessive matrix metalloproteinase (MMP) levels have been observed in wound fluid of impaired healing wounds. This is thought to interfere with granulation tissue formation as newly formed extracellular matrix and cytokines are degraded and the wound becomes deadlocked, unable to progress to the next healing stages. In the cleansing phase, associated with high MMP activity levels, hydroactive wound dressings containing polyacrylate superabsorber particles are particularly effective. We tested whether these particles can block MMP activity in wound fluid obtained from chronic venous leg ulcers. Polyacrylate superabsorber particles inhibited MMP activity by more than 87% in a fluorogenic peptide substrate assay. Further analysis revealed two underlying molecular mechanisms. First, experiments showed direct binding of MMPs to the particles. Secondly, polyacrylate superabsorber particles can bind Ca2+ and Zn2+ ions competing with MMPs for divalent ions required for enzymatic activity. Furthermore, we provide the first evidence in vivo that MMPs bind effectively to polyacrylate superabsorber particles within the hostile environment of chronic wounds. We conclude that polyacrylate superabsorber particles can rescue the highly proteolytic microenvironment of non-healing wounds from MMP activity so that more conductive conditions allow healing to proceed.     

Connecting thalamus and cortex: the role of ephrins

The complex task of wiring up the brain during embryonic development is achieved by a multitude of guidance signals acting in complex combinations to drive growing axons to their proper targets. The somatosensory system provides an extensively studied model system featuring many universal mechanisms of neural development. In rodents, it constitutes an important model to study how precise topographic connections are achieved. Recent evidence suggests that the Eph/ephrin family of guidance molecules is of pivotal importance for the development of the somatosensory system. Members of Eph/ephrin family are thought to be involved in the global presorting of thalamic axons projecting to the cortex, in labeling specific cortical areas for innervation, in providing topographic cues within the target area, and in distinguishing cortical layers for intracortical wiring. The Eph/ephrin system also seems to contribute to the formation of specific corticothalamic feedback projections. So far, the functions of only a few members of the Eph/ephrin family have been examined, but expression analysis indicates complex combinatorial effects of these signaling molecules. Understanding the Eph/ephrin wiring code is expected to yield new insights into the development and plasticity of brain circuits involved in higher functions.     

Interaction of blood sera from patients with autoimmune diseases with expressed cDNA fragment of topoisomerase I and with monoclonal antibodies to the enzyme

V. A. Éngel'gardt Institute of Molecular Biology, Academy of Sciences of the USSR. Institute of Rheumatology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR I. B. Zbarskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 12, pp. 598–600, December, 1990.     

Left ventricular dyssynchrony assessment by phase analysis from gated PET-FDG scans

Background

The outcome of patients with severe ischaemic left ventricular (LV) dysfunction is determined by the extent of myocardial viability and the presence of LV dyssynchrony. We aimed at assessing both parameters from the same imaging method, i.e. gated positron emission tomography (PET) F18-fluorodeoxyglucose (FDG) scans.

Methods

Phase analysis from Emory Cardiac Toolbox was applied on gated PET-FDG scans to assess histogram bandwidth and standard deviation (SD) as a measure of LV dyssynchrony in 30 heart failure patients (mean ejection fraction: 30.2% ± 13.8%) referred for the evaluation of myocardial viability. Cut-off values from single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) best predicting cardiac resynchronization therapy (CRT) response served as standard of reference (bandwidth < 135°; phase SD < 43°). Severe LV dyssynchrony was diagnosed if both SPECT-MPI values were above these limits. Intraclass correlation and clinical agreement in detection of severe LV dyssynchrony by PET vs SPECT were assessed.

Results

There was a significant correlation between PET-FDG and SPECT-MPI for bandwidth (r = 0.88, P < .001) and phase SD (r = 0.88, P < .001) resulting in an excellent clinical agreement between the two methods of 93%.

Conclusions

Accurate LV dyssynchrony assessment by phase analysis of gated PET-FDG scans is feasible, allowing assessing myocardial viability and severe LV dyssynchrony in one scan.