Asymmetric 1,3-dipolar cycloaddition reactions between enals and nitrones catalysed by half-sandwich rhodium or iridium diphosphane complexes

The aqua complexes ¿(¿5-C5Me5)M¿PP*)¿H2O)]¿SbF6]2 (M = Rh, Ir; PP* = chiral diphosphane) have been tested as catalysts for the asymmetric 1,3-dipolar cycloaddition of nitrones to a,ß-unsaturated aldehydes. Quantitative conversions with very high regioselectivity, perfect endo selectivity and excellent enantioselectivity (up to 99% ee) were achieved. The stereochemical outcome was analyzed on the basis of the stereoelectronic properties of the intermediate enal complexes of the formula ¿(¿5-C5Me5)M¿PP*)¿enal)]¿SbF6]2

The Safety and Feasibility of Transitioning From Transfemoral to Transradial Access Left Ventricular Endomyocardial Biopsy

BACKGROUND: Left ventricular endomyocardial biopsy (LVEMB) is commonly performed via the transfemoral route. Radial access may help reduce vascular access complications, but there are few data on the safety and feasibility of transradial LVEMB. OBJECTIVE: Describe the safety and feasibility of transitioning from transfemoral to transradial access LVEMB. METHODS: This is a single-center, prospective, observational cohort study. Fifty procedures in 49 patients were included, 25 (50%) via the femoral route and 25 (50%) via the radial route. RESULTS: The cohort had a mean age of 47 ± 13 years and the most common indication for LVEMB was myocarditis. From June 2015 until September 2016, all procedures (n = 21) were performed via the femoral approach; thenceforth, there was a gradual transition to the radial approach. More tissue samples were obtained when the procedure was performed via the femoral approach (P<.01). The minimum sampling target of 3 specimens was not met in 4 patients (16%) via the radial approach and in 1 patient (4%) via the femoral approach. Complications occurred in 3/25 transradial procedures (12%; 2 cardiac perforations and 1 forearm hematoma) and 3/25 transfemoral procedures (12%; 1 cardiac perforation, 1 femoral artery pseudoaneurysm, and 1 ventricular fibrillation). Cardiac perforations via the transradial approach occurred during the early transition period. There were no deaths. CONCLUSIONS: Transradial LVEMB is feasible, with a similar complication profile to femoral procedures, but associated with a smaller number of specimens. Transitioning from transfemoral to transradial procedures may initially be associated with a higher risk of complications and potentially a lower diagnostic yield

New Alloying Systems for Sintered Steels: Critical Aspects of Sintering Behavior

Oxygen-sensitive alloying elements such as Mn, Si, and Cr have a high potential for improving the properties of low alloyed sintered steels while reducing the alloying cost. However, it is necessary to find a way for avoiding, or at least minimizing, the oxidation of these elements especially during the early stages of the sintering cycle. In this study Mn, Si, and Cr were introduced in the form of a master alloy powder designed to be mixed with the iron base powder and provide the final composition of the steel during the sintering process. The reduction/oxidation phenomena taking place during the heating stage were studied by thermogravimetry, dilatometry, and mass spectroscopy, using either reducing (H2) or inert (Ar) atmospheres. The results show how the difference in chemical activity between base iron powder and master alloy causes the so called "internal-getter" effect, by which the reduction of less stable iron oxides leads to oxidation of the elements with higher affinity for oxygen. This effect can be somehow minimized when sintering in H2, since the iron oxides are reduced at lower temperatures at which the reactivity of the elements in the master alloy is lower. However, H2 concentration in the processing atmosphere needs to be carefully adapted to the specific composition of the materials being processed in order to minimize decarburization by methane formation during sintering.Höganäs AB Sweden, financial support provided through the Höganäs Chair IVPublicad

Analytical methods in wineries: is it time to change?

A review of the methods for the most common parameters determined in wine—namely, ethanol, sulfur dioxide, reducing sugars, polyphenols, organic acids, total and volatile acidity, iron, soluble solids, pH, and color—reported in the last 10 years is presented here. The definition of the given parameter, official and usual methods in wineries appear at the beginning of each section, followed by the methods reported in the last decade divided into discontinuous and continuous methods, the latter also are grouped in nonchromatographic and chromatographic methods because of the typical characteristics of each subgroup. A critical comparison between continuous and discontinuous methods for the given parameter ends each section. Tables summarizing the features of the methods and a conclusions section may help users to select the most appropriate method and also to know the state-of-the-art of analytical methods in this area

Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration

In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life1, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge2 are regulated by the surrounding microenvironment, or niche3. The activation of such stem cells is cyclic, involving periodic -catenin activity4, 5, 6, 7. In the adult mouse, regeneration occurs in waves in a follicle population, implying coordination among adjacent follicles and the extrafollicular environment. Here we show that unexpected periodic expression of bone morphogenetic protein 2 (Bmp2) and Bmp4 in the dermis regulates this process. This BMP cycle is out of phase with the WNT/-catenin cycle, thus dividing the conventional telogen into new functional phases: one refractory and the other competent for hair regeneration, characterized by high and low BMP signalling, respectively. Overexpression of noggin, a BMP antagonist, in mouse skin resulted in a markedly shortened refractory phase and faster propagation of the regenerative wave. Transplantation of skin from this mutant onto a wild-type host showed that follicles in donor and host can affect their cycling behaviours mutually, with the outcome depending on the equilibrium of BMP activity in the dermis. Administration of BMP4 protein caused the competent region to become refractory. These results show that BMPs may be the long-sought 'chalone' inhibitors of hair growth postulated by classical experiments. Taken together, results presented in this study provide an example of hierarchical regulation of local organ stem cell homeostasis by the inter-organ macroenvironment. The expression of Bmp2 in subcutaneous adipocytes indicates physiological integration between these two thermo-regulatory organs. Our findings have practical importance for studies using mouse skin as a model for carcinogenesis, intra-cutaneous drug delivery and stem cell engineering studies, because they highlight the acute need to differentiate supportive versus inhibitory regions in the host skin

The red leg dilemma: a scoping review of the challenges of diagnosing lower limb cellulitis

Background: Suspected lower limb cellulitis presentations are commonly misdiagnoses, resulting in avoidable antibiotic prescribing or hospital admissions. Understanding the challenges posed in diagnosing cellulitis may help enhance future care.Objectives: To examine and map out the challenges and facilitators identified by patients and health professionals in diagnosing lower limb cellulitis.Methods: A scoping systematic review was performed in MEDLINE and Embase in October 2017. Thematic analysis was used to identify key themes. Quantitative data was summarised by narrative synthesis.Results: Three themes were explored: (i) clinical case reports of misdiagnosis, (ii) service development and (iii) diagnostic aids. Forty‐seven different pathologies were misdiagnosed, including seven malignancies. Two different services have been piloted to reduce the misdiagnosis rates of lower limb cellulitis and save costs. Four studies have looked at biochemical markers, imaging and a scoring tool to aid diagnosis.Conclusions: This review highlights the range of alternative pathologies that can be misdiagnosed as cellulitis, and emerging services and diagnostic aids developed to minimise misdiagnosis. Future work should focus on gaining a greater qualitative understanding of the diagnostic challenges from the perspective of patients and clinicians.This article is protected by copyright. All rights reserved