Thermal Alteration in Adsorption Sites over SAPO-34 Zeolite.

Zeolites have found tremendous applications in the chemical industry. However, the dynamic nature of their active sites under the flow of adsorbate molecules for adsorption and catalysis is unclear, especially in operando conditions, which could be different from the as-synthesized structures. In the present study, we report a structural transformation of the adsorptive active sites in SAPO-34 zeolite by using acetone as a probe molecule under various temperatures.

Interstitial and substitutional light elements in transition metals for heterogeneous catalysis.

The addition of foreign element dopants to monometallic nanoparticle catalysts is of great importance in industrial applications. Both substitutional and interstitial doping of pure metallic phases can give profound effects such as altering electronic and transport properties, lattice parameters, phase transitions, and consequently various physicochemical properties. For transition metal catalysts, this often leads to changes in catalytic activity and selectivity.

Direct Visualization of Substitutional Li Doping in Supported Pt Nanoparticles and Their Ultra-selective Catalytic Hydrogenation Performance.

It has only recently been established that doping light elements (lithium, boron, and carbon) into supported transition metals can fill interstitial sites, which can be observed by the expanded unit cell. As an example, interstitial lithium ( Li) can block H filling octahedral interstices of palladium metal lattice, which improves partial hydrogenation of alkynes to alkenes under hydrogen. In contrast, herein, we report Li is not found in the case of Pt/C.

Induced Active Sites by Adsorbate in Zeotype Materials.

There has been a long debate on how and where active sites are created for molecular adsorption and catalysis in zeolites, which underpin many important industrial applications. It is well accepted that Lewis acidic sites (LASs) and basic sites (LBSs) as active sites in pristine zeolites are generally believed to be the extra-framework Al species and residue anion (OH) species formed at fixed crystallographic positions after their synthesis. However, the dynamic interactions of adsorbates/reactants with pristine zeotype materials to "create" sites during real conditions remain largely unexplored.

Characterisation of oxygen defects and nitrogen impurities in TiO photocatalysts using variable-temperature X-ray powder diffraction.

TiO-based powder materials have been widely studied as efficient photocatalysts for water splitting due to their low cost, photo-responsivity, earthly abundance, chemical and thermal stability, etc. In particular, the recent breakthrough of nitrogen-doped TiO, which enhances the presence of structural defects and dopant impurities at elevated temperatures, exhibits an impressive visible-light absorption for photocatalytic activity. Although their electronic and optical properties have been extensively studied, the structure-activity relationship and photocatalytic mechanism remain ambiguous.

T-cell receptor-gamma gene analysis in evolving to advancing cutaneous T-cell lymphoma.

The diagnosis of cutaneous T-cell lymphoma is often a challenge for the dermatopathologist. Early stages can mimic inflammatory dermatoses. Our aim was to explore the applicability of a standard T-cell receptor-gamma polymerase chain reaction in various subtypes of cutaneous T-cell lymphomas.

Squamous cell carcinoma and Bowen's disease of the skin in Singapore.

Introduction: Non-melanoma skin cancer is one of the commonest cancers in Singapore and worldwide. The aim of our study was to evaluate the demographic and clinicopathological patterns of squamous cell carcinoma (SCC) and Bowen's disease (BD) of the skin, in order to better understand the characteristics of these tumours in our population.

Materials And Methods: Histologically proven cases of SCC and BD seen at our centre between 2002 and 2003 were retrospectively analysed according to age, sex, race, predisposing factors such as immunosuppression and ultraviolet therapy, site and size of tumour, histological differentiation and subtype, and treatment method.

Calciphylaxis with a protracted course in a patient with end-stage renal failure.

Calciphylaxis is a rare condition with a high mortality involving mural calcification of small vessels and occurring primarily in patients with end-stage renal disease. Most cases are characterized by rapid progression of tender subcutaneous nodules or cutaneous plaques to epidermal necrosis, with death in the majority of cases occurring from sepsis. The condition is still poorly understood and the pathogenesis not known.

Juvenile elastoma: a forme fruste of the Buschke-Ollendorff syndrome?

We describe an Asian child with juvenile elastoma who presented to us at 9 years of age with flesh-coloured nodules on his thigh. Histologically, H&E sections were normal, but elastin stains showed collections of increased and thickened elastic fibres consistent with juvenile elastoma. Radiological examination did not demonstrate osteopoikilosis.

Retrospective review of the correlation of symptoms, signs and microscopy with the diagnosis of Chlamydia trachomatis in men.

We have investigated the correlation of symptoms, signs and microscopy on the detection of Chlamydia trachomatis infection in men attending our clinic. One hundred and eleven men diagnosed with chlamydia over an 11-month period in our clinic were reviewed. Of these, 70 (63%) were symptomatic and 41 (37%) were asymptomatic.