Catalytic Conversion of Methane to Methanol Using Cu-Zeolites

The conversion of methane to value-added liquid chemicals is a promising answer to the imminent demand for fuels and chemical synthesis materials in the advent of a dwindling petroleum supply. Current technology requires high energy input for the synthesis gas production, and is characterized by low overall selectivity, which calls for alternative reaction routes. The limitation to achieve high selectivity is the high C–H bond strength of methane. High-temperature reaction systems favor gas-phase radical reactions and total oxidation. This suggests that the catalysts for methane activation should be active at low temperatures. The enzymatic-inspired metal-exchanged zeolite systems apparently fulfill this need, however, methanol yield is low and a catalytic process cannot yet be established. Homogeneous and heterogeneous catalytic systems have been described which stabilize the intermediate formed after the first C–H activation. The understanding of the reaction mechanism and the determination of the active metal sites are important for formulating strategies for the upgrade of methane conversion catalytic technologies

The decay of Batchelor and Saffman rotating turbulence

The decay rate of isotropic and homogeneous turbulence is known to be affected by the large-scale spectrum of the initial perturbations, associated with at least two cannonical self-preserving solutions of the von K\'arm\'an-Howarth equation: the so-called Batchelor and Saffman spectra. The effect of long-range correlations in the decay of anisotropic flows is less clear, and recently it has been proposed that the decay rate of rotating turbulence may be independent of the large-scale spectrum of the initial perturbations. We analyze numerical simulations of freely decaying rotating turbulence with initial energy spectra $\sim k^4$ (Batchelor turbulence) and $\sim k^2$ (Saffman turbulence) and show that, while a self-similar decay cannot be identified for the total energy, the decay is indeed affected by long-range correlations. The decay of two-dimensional and three-dimensional modes follows distinct power laws in each case, which are consistent with predictions derived from the anisotropic von K\'arm\'an-Howarth equation, and with conservation of anisotropic integral quantities by the flow evolution

The Del1 deposition domain can immobilize 3α-hydroxysteroid dehydrogenase in the extracellular matrix without interfering with enzymatic activity

Developing methods that result in targeting of therapeutic molecules in gene therapies to target tissues has importance, as targeting can increase efficacy and decrease off target-side-effects. Work from my laboratory previously showed that the extracellular matrix protein Del1 is organized in the extracellular matrix (ECM) via the Del1 deposition domain (DDD). In this work, a fusion protein with DDD was made to assay the ability to immobilize an enzyme without disrupting enzymatic function. A prostatic cancer-derived cell line LNCap that grows in an androgen-dependent manner was used with 3α-hydroxysteroid dehydrogenase (3 αHD), which catalyzes dihydrotestosterone (DHT). Plasmids encoding a 3αHD:DDD fusion were generated and transfected into cultured cells. The effects of 3αHD immobilized in the ECM by the DDD were evaluated by monitoring growth of LNCap cells and DHT concentrations. It was demonstrated that the DDD could immobilize an enzyme in the ECM without interfering with function

Identification of signaling pathways in early mammary gland development by mouse genetics

The mammary gland develops as an appendage of the ectoderm. The prenatal stage of mammary development is hormone independent and is regulated by sequential and reciprocal signaling between the epithelium and the mesenchyme. A number of recent studies using human and mouse genetics, in particular targeted gene deletion and transgenic expression, have identified some of the signals that control specific steps in development. This process involves cell specification and proliferation, reciprocal tissue interactions and cell migration. Since some of these events are recapitulated during tumorigenesis, an understanding of these signaling pathways may contribute to the development of targeted therapies and novel drugs

The effect of watchful waiting compared to immediate test ordering instructions on general practitioners' blood test ordering behaviour for patients with unexplained complaints; a randomized clinical trial (ISRCTN55755886)

<p>Abstract</p> <p>Background</p> <p>Immediate blood testing for patients presenting with unexplained complaints in family practice is superfluous from a diagnostic point of view. However, many general pracitioners (GPs) order tests immediately. Watchful waiting reduces the number of patients to be tested and the number of false-positive results. The objectives of this study are: to determine the feasibility of watchful waiting compared to immediate test ordering; to determine if a special quality improvement strategy can improve this feasibility; and to determine if watchful waiting leads to testing at a later time.</p> <p>Methods</p> <p>The study is a cluster-randomized clinical trial with three groups, on blood test ordering strategies in patients with unexplained complaints. GPs in group one were instructed to order tests immediately and GPs in group two to apply a watchful waiting approach. GPs in group three received the same instruction as group two, but they were supported by a systematically designed quality improvement strategy. A total of 498 patients with unexplained complaints from 63 practices of Dutch GPs participated. We measured: the percentage of patients for whom tests were ordered and number of tests ordered at the first consultation; performance on the strategy's performance objectives (i.e., ordering fewer tests and specific communication skills); the number of tests ordered after four weeks; and GP and patient characteristics.</p> <p>Results</p> <p>Immediate test ordering proved feasible in 92% of the patients; watchful waiting in 86% and 84%, respectively, for groups two and three. The two watchful waiting groups did not differ significantly in the achievement of any of the performance objectives. Of the patients who returned after four weeks, none from group one and six from the two watchful waiting groups had tests ordered for them.</p> <p>Conclusions</p> <p>Watchful waiting is a feasible approach. It does not lead to testing immediately afterwards. Furthermore, watchful waiting was not improved by the quality improvement strategy.</p> <p>Trial registration</p> <p>Clinical trial registration: <a href="http://www.controlled-trials.com/ISRCTN55755886">ISRCTN55755886</a></p

Can Energetic Terahertz Pulses Initiate Surface Catalytic Reactions on the Picosecond Time Scale?

In preparation for picosecond pump-probe experiments at the SwissFELX-ray laser facility, the feasibility of collectively initiating surface chemical reactions using energetic pulses of terahertz radiation is being tested

Blood test ordering for unexplained complaints in general practice: the VAMPIRE randomised clinical trial protocol. [ISRCTN55755886]

BACKGROUND: General practitioners (GPs) frequently order blood tests when they see patients presenting with unexplained complaints. Due to the low prevalence of serious pathology in general practice, the risk of false-positive test results is relatively high. This may result in unnecessary further testing, leading to unfavourable effects such as patient anxiety, high costs, somatisation and morbidity. A policy of watchful waiting is expected to lower both the number of patients to be tested and the risk of false-positive test results, without missing serious pathology. However, many general practitioners experience barriers when trying to postpone blood testing by watchful waiting. The objectives of this study are (1) to determine the accuracy of blood tests in patients presenting with unexplained complaints in terms of detecting pathology, (2) to determine the accuracy of a watchful waiting strategy and (3) to determine the effects of a quality improvement strategy to promote the postponement of blood test ordering by GPs for patients with unexplained complaints. DESIGN: General practices are randomised over three groups. Group 1 is instructed to order blood tests immediately, group 2 to apply a watchful waiting policy and group 3 also to postpone testing, but supported by our quality improvement strategy. The trial consists of two sub-studies: a diagnostic study at patient level (group 1 versus groups 2 and 3) and a quality improvement study at GP level (group 2 versus group 3). The diagnostic strategy to be used involves of both customary and innovative tests. The quality improvement strategy consists of two small-group meetings and a practice outreach visit. Patient follow-up ends at 12 months after the initial consultation. Primary outcome measures are the accuracy and added value of blood tests for detecting pathology, the effect of a 4-week postponement of test ordering on the blood test characteristics and the quantity of tests ordered. Secondary outcome measures are the course of complaints, quality of life, satisfaction with care, anxiety of patients and practitioners, determinants of physicians' behaviour, health care utilisation and costs. DISCUSSION: The innovative aspect of this trial is that it combines a clinical-epidemiological study and a quality of care study