The effect of Mg location on Co-Mg-Ru/γ-Al2O3 Fischer-Tropsch catalysts

The effectiveness of Mg as a promoter of Co-Ru/γ-Al2O3 Fischer-Tropsch catalysts depends on how and when the Mg is added. When the Mg is impregnated into the support before the Co and Ru addition, some Mg is incorporated into the support in the form of MgxAl2O3+x if the material is calcined at 550°C or 800°C after the impregnation, while the remainder is present as amorphous MgO/MgCO3 phases. After subsequent Co-Ru impregnation MgxCo3-xO4 is formed which decomposes on reduction, leading to Co(0) particles intimately mixed with Mg, as shown by high-resolution transmission electron microscopy. The process of impregnating Co into an Mg-modified support results in dissolution of the amorphous Mg, and it is this Mg which is then incorporated into MgxCo3-xO4. Acid washing or higher temperature calcination after Mg impregnation can remove most of this amorphous Mg, resulting in lower values of x in MgxCo3-xO4. Catalytic testing of these materials reveals that Mg incorporation into the Co oxide phase is severely detrimental to the site-time yield, while Mg incorporation into the support may provide some enhancement of activity at high temperature.

Graphite-Conjugated Rhenium Catalysts for Carbon Dioxide Reduction

Condensation of fac-Re(5,6-diamino-1,10-phenanthroline)(CO)3Cl to o-quinone edge defects on graphitic carbon surfaces generates graphite-conjugated rhenium (GCC-Re) catalysts that are highly active for CO2 reduction to CO in acetonitrile electrolyte. X-ray photoelectron and X-ray absorption spectroscopies establish the formation of surface-bound Re centers with well-defined coordination environments. GCC-Re species on glassy carbon surfaces display catalytic currents greater than 50 mA cm(-2) with 96 ± 3% Faradaic efficiency for CO production. Normalized for the number of Re active sites, GCC-Re catalysts exhibit higher turnover frequencies than that of a soluble molecular analogue, fac-Re(1,10-phenanthroline)(CO)3Cl, and turnover numbers greater than 12,000. In contrast to the molecular analogue, GCC-Re surfaces display a Tafel slope of 150 mV/decade, indicative of a catalytic mechanism involving rate-limiting one-electron transfer. This work establishes graphite-conjugation as a powerful strategy for generating well-defined, tunable, heterogeneous electrocatalysts on ubiquitous graphitic carbon surfaces.

Pd–In intermetallic alloy nanoparticles: highly selective ethane dehydrogenation catalysts

2 nm PdIn intermetallic alloy (cubic, CsCl type) nanoparticle catalyst was near 100% selective to ethane dehydrogenation at 600 °C (at 15% conversion) with a dehydrogenation TOR almost 10 times higher than that of monometallic Pd.

Organometallic model complexes elucidate the active gallium species in alkane dehydrogenation catalysts based on ligand effects in Ga K-edge XANES

Ga(iii)-alkyl and alkoxide model compounds demonstrate XANES edge energy shifts similar to those in Ga dehydrogenation catalysts without a change in Ga oxidation state.

A Hafnium-Based Metal-Organic Framework as a Nature-Inspired Tandem Reaction Catalyst

Tandem catalytic systems, often inspired by biological systems, offer many advantages in the formation of highly functionalized small molecules. Herein, a new metal-organic framework (MOF) with porphyrinic struts and Hf6 nodes is reported. This MOF demonstrates catalytic efficacy in the tandem oxidation and functionalization of styrene utilizing molecular oxygen as a terminal oxidant. The product, a protected 1,2-aminoalcohol, is formed selectively and with high efficiency using this recyclable heterogeneous catalyst. Significantly, the unusual regioselective transformation occurs only when an Fe-decorated Hf6 node and the Fe-porphyrin strut work in concert. This report is an example of concurrent orthogonal tandem catalysis.

A retrospective analysis of dentofacial deformities and orthognathic surgeries using the index of orthognathic functional treatment need (IOFTN)

OBJECTIVES

To assess the functional needs of orthognathic cases treated in Northampton General Hospital using the index of orthognathic functional treatment need (IOFTN).

MATERIALS AND METHODS

A retrospective study was conducted on 78 subjects (54 female and 24 males, 10-54 years, mean (SD) age=21.88 (6.98) years) who had orthognatic surgery in Northampton General Hospital or were in preparation for it (5 case). The sample represents a period between February 1997 and December 2014. The components of IOFTN and Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) as well as Malocclusion type were recorded.

RESULTS

Class III malocclusion/skeletal pattern was the most prevalent type (approximately 49%). There were 1, 36, 3, and 38 subjects with Class I, Class II Division I, Class II Division II, and Class III malocclusions, respectively. In terms of sagittal skeletal relationship, there were 2, 37, and 39 subjects with Class I, Class II, and Class III skeletal bases, respectively. The most prevalent IOFTN score in our sample was the 5.2 (29.5%), followed by 5.3 (15.5%), 4.2 (13%), 4.3 (11.5%). Overall, 92.3% were classified as in great and very great functional needs according to the IOFTN. Similarly, 84.6% scored as grade 4 or 5, according to the IOTN (DHC). The bimaxillary type osteotomy was the most prevalent type (61.5%).

CONCLUSIONS

Using IOFTN, 92.3% of our sample were classified as having great and very great functional needs. IOFTN is a simple and reliable tool to identify patients in need of orthognathic surgery and can be used in resource allocation for patients with highest functional needs.

Air- and water-resistant noble metal coated ferromagnetic cobalt nanorods

Cobalt nanorods possess ideal magnetic properties for applications requiring magnetically hard nanoparticles. However, their exploitation is undermined by their sensitivity toward oxygen and water, which deteriorates their magnetic properties. The development of a continuous metal shell inert to oxidation could render them stable, opening perspectives not only for already identified applications but also for uses in which contact with air and/or aqueous media is inevitable. However, the direct growth of a conformal noble metal shell on magnetic metals is a challenge. Here, we show that prior treatment of Co nanorods with a tin coordination compound is the crucial step that enables the subsequent growth of a continuous noble metal shell on their surface, rendering them air- and water-resistant, while conserving the monocrystallity, metallicity and the magnetic properties of the Co core. Thus, the as-synthesized core-shell ferromagnetic nanorods combine high magnetization and strong uniaxial magnetic anisotropy, even after exposure to air and water, and hold promise for successful implementation in in vitro biodiagnostics requiring probes of high magnetization and anisotropic shape.

Proxy-based accelerated discovery of Fischer-Tropsch catalysts

High-throughput XRD and TGA are used to screen hundreds of candidate Fischer–Tropsch synthesis catalyst samples per month for particle size, reducibility and stability under operating conditions. A series of highly stable catalysts based on Co-Ru-Mg-Al₂O₃ are identified.

Development of heterogeneous catalysts for complex reactions such as Fischer–Tropsch synthesis of fuels is hampered by difficult reaction conditions, slow characterisation techniques such as chemisorption and temperature-programmed reduction and the need for long term stability. High-throughput (HT) methods may help, but their use has until now focused on bespoke micro-reactors for direct measurements of activity and selectivity. These are specific to individual reactions and do not provide more fundamental information on the materials. Here we report using simpler HT characterisation techniques (XRD and TGA) along with ageing under Fischer–Tropsch reaction conditions to provide information analogous to metal surface area, degree of reduction and thousands of hours of stability testing time for hundreds of samples per month. The use of this method allowed the identification of a series of highly stable, high surface area catalysts promoted by Mg and Ru. In an advance over traditional multichannel HT reactors, the chemical and structural information we obtain on the materials allows us to identify the structural effects of the promoters and their effects on the modes of deactivation observed.

Structural evolution of an intermetallic Pd–Zn catalyst selective for propane dehydrogenation

Formation of PdZn intermetallic nanoalloys selective for propane dehydrogenation tracked using in situ synchrotron XRD.

In situ diffraction of highly dispersed supported platinum nanoparticles

In situ synchrotron diffraction in H₂ reveals structural and microstructural details of supported 1–2 nm Pt nanoparticles.

Odontogenic cervico-fascial infections: a continuing threat

STATEMENT OF THE PROBLEM

Dental abscesses are common and occasionally can progress to life-threatening cervico-fascial infections. Despite medical advances, odontogenic cervico-fascial infections (OCFIs) continue to be a threat. The potential seriousness of odontogenic infections (Ols), or dental abscesses, is frequently underestimated. General dental practitioners (GDPs) in primary care face the challenging decision of whether to refer patients to secondary care or to manage them in the community.

PURPOSE OF THE REVIEW

This paper reviews the relevant aspects of Ols that might be helpful to primary care dental practitioners in providing a better understanding of the anatomy and pathology and aims to assist in clinical decision.

METHOD

An up-to-date review of literature on OCFIs, highlighting their potential risks with clinical examples.

RESULTS AND CONCLUSION

Dental abscesses are common and continue to be a major cause for emergency hospital admission to oral and maxillofacial surgery departments. They occasionally spread to fascial spaces of the neck, potentially posing significant morbidity and mortality. GDPs are usually the first point of contact and face the challenge of recognising those at risk of developing OCFIs, which are potentially life threatening and require urgent referral for hospital treatment. We propose a patient care pathway to be used in primary care.

Pedicled genial osteotomy modification of the mandibular release access operation for access to the back of the tongue

We report a modification of the operation of mandibular release or 'visor drop down'. It allows more accurate repositioning and more permanent fixation of the genioglossus, geniohyoid, and digastric muscles using a small anterior osteotomy. We hope that this more accurate and reliable repositioning will give improved outcomes in terms of speech, chewing, and swallowing.

Identification and overexpression of human neutrophil α-defensins (human neutrophil peptides 1, 2 and 3) in squamous cell carcinomas of the human tongue

To date, little attention has been paid to the possible role of alpha-defensins (human neutrophil peptides 1-3), HNP-1, HNP-2 and HNP-3 in innate host defence against tumour invasion. In the current study, using a single-dimensional high pressure liquid chromatography (HPLC) method for peptide separation, followed by mass spectrometry and amino acid sequencing for identification and quantitation, we report the overexpression of HNP-1, HNP-2 and HNP-3 in squamous cell carcinomas of the human tongue compared with autogenous non-tumour tissue. Using a specific antibody we show that the defensins are abundant in neutrophils infiltrating human oral squamous cell carcinoma tissue. In the context of their previously reported oncolytic activity, our results may imply a role for alpha-defensins in host defence against oral squamous cell carcinoma.

Microbial desulfurization of dibenzothiophene: a sulfur-specific pathway

Rhodococcus rhodochrous strain IGTS8 metabolizes dibenzothiophene, a model compound for organic sulfur in fossil fuels, in a sulfur-specific manner. Two routes of desulfurization have been identified. Under growth conditions, the intermediates are dibenzothiophene sulfoxide, dibenzothiophene sulfone, 2'-hydroxybiphenyl-2-sulfonate, and 2,2'-dihydroxybiphenyl. Stationary phase cells produce 2-hydroxybiphenyl as the desulfurized product and use the 2'-hydroxybiphenyl-2-sulfinate, rather than the sulfonate, as the key intermediate.

Violating assumptions of statistical procedures: JHCM reporting guidelines

JHCM authors have a responsibility to provide enough information for the reader to evaluate reported study conclusions and implications adequately, and to do so without overshadowing attention to statistical detail. Guidelines are presented for discussing the assumptions and requirements underlying the statistical procedures used, including what to report when there are violations.

Listening to the consumer: implications of a statewide study of North Carolinians

To be successful in an increasingly competitive health care marketplace, physicians and other providers must understand the motives, needs, and preferences of patients and potential patients. The author reports findings from a statewide study of North Carolina consumers that provide insight into consumer awareness and utilization of various physician specialists, desirable physician practice attributes, and other regnant consumer preferences and perceptions.

The nutritional status of pregnant and non-pregnant mares grazing South East Queensland pastures

It has been reported that the increasing nutritional demands from mid to late pregnancy of grazing mares may not be met when these stages of gestation coincide with pastures being affected by frost. It was established in this study that grass/legume pastures could support the nutritional requirements of brood mares by providing digestible energy intakes of 68.0 and 91.7 MJ/day and digestible nitrogen intake of 91.2 and 138 g/day during mid and late pregnancy, respectively.

Inhibition of brain monoamine oxidase by 1,2,4-trisubstituted 5-imidazolones

Nine 1-(3,4-dimethoxyphenethyl)-2-methyl-4-(substituted benzylidene)-5- imidazolones were evaluated for their ability to inhibit the activity of rat brain monoamine oxidase during oxidative deamination of tyramine, 5-hydroxytryptamine (serotonin), and kynuramine. All substituted imidazolones inhibited monoamine oxidase activity. A concentration-dependent inhibition of monoamine oxidase was observed using kynuramine as the substrate and the degree of enzyme inhibition was also evaluated on the basis of their I50 values. Preincubation of imidazolones with the enzyme preparations for varying lengths of time prior to the addition of substrate in no way altered their degree of inhibition and thus exhibited a reversible nature of inhibition. A kinetic study carried out with 1-(3,4-dimethoxy-phenethyl)-2-methyl-4-(4- nitrobenzylidene )-5- i midazolone revealed a competitive nature of inhibition of rat brain monoamine oxidase.

The origins, development, and goals of adolescent medicine

This essay offers the author's recollections and opinions on such topics as when and why an interest in adolescents' medical care originated, under what circumstances those developments occurred which preceded and soon followed the recognition of Adolescent Medicine by medical schools and hospitals, and the goals of those physicians who pursued that interest. It attempts to recount and document the events, circumstances, persons, and groups of people associated with the emergence and early development of this venture into the medical care of yet another age-group.