High catalytic activity of CuY catalysts prepared by high temperature anhydrous interaction for the oxidative carbonylation of methanol

CuY catalysts were prepared by high temperature anhydrous interaction between NH₄Y zeolite and copper(ii) acetylacetonate Cu(acac)₂ and the activities were measured for the oxidative carbonylation of methanol to dimethyl carbonate under atmospheric pressure. The bulk and surface properties of the as-prepared catalyst were characterized by XRD, H₂-TPR and XPS techniques. The activation atmosphere of the CuY catalyst and the testing temperature of the catalytic activity was systematically studied. During activation, nitrogen promotes the auto-reduction of Cu²⁺ to form the Cu⁺ active center, but deposited carbon on the surface of the CuY catalyst covers the active center, even plugging the channel, resulting in lower catalytic activity. Oxygen eliminates deposited carbon, but is not so good for the auto-reduction of Cu²⁺. Nitrogen doped with a small amount of oxygen not only eliminates the deposited carbon, but also promotes the auto-reduction of Cu²⁺ to form more Cu⁺ active centers. With the testing temperature increasing, the catalytic activity increases first and then decreases. When the testing temperature is 170 °C, the CuY catalyst with satisfactory activity and stability showed an excellent catalytic activity with 525.1 mg g⁻¹ h⁻¹ space time yield of DMC (STY_DMC) and 18.9% methanol conversion. Then the longevity was investigated at 170 °C for 150 h. During the initial reaction period of 40 h, the STY_DMC value was constant. In the next 20 h, the catalytic activity slightly decreased. But in the last 90 h, the catalytic performance is very stable and the STY_DMC value remains 480 mg g⁻¹ h⁻¹. The main cause of deactivation is the growth of the particles.

The CuY catalysts prepared by high temperature anhydrous interaction were activated under different atmospheres and the activities were measured for the oxidative carbonylation of methanol to dimethyl carbonate under atmospheric pressure.     

Three-dimensional computed tomography mapping of posterior malleolar fractures

BACKGROUND Posterior malleolar fractures have been reported to occur in<40%of ankle fractures.AIM To reveal the recurrent patterns and characteristics of posterior malleolar fractures by creating fracture maps of the posterior malleolar fractures through the use of computed tomography mapping.METHODS A consecutive series of posterior malleolar fractures was used to create threedimensional reconstruction images,which were oriented and superimposed to fit an ankle model template by both aligning specific biolandmarks and reducing reconstructed fracture fragments.Fracture lines were found and traced in order to generate an ankle fracture map.RESULTS This study involved 112 patients with a mean age of 49,comprising 32 pronationexternal rotation grade IV fractures and 80 supination-external rotation grade IV fractures according to the Lauge-Hansen classification system.Three-dimensional maps showed that the posterior ankle fracture fragments in the supinationexternal rotation grade IV group were relatively smaller than those in the pronation-external rotation grade IV group after posterior malleolus fracture.In addition,the distribution analyses on posterior malleolus fracture lines indicated that the supination-external rotation grade IV group tended to have higher linear density but more concentrated and orderly distribution fractures compared to the pronation-external rotation grade IV group.CONCLUSION Fracture maps revealed the fracture characteristics and recurrent patterns of posterior malleolar fractures,which might help to improve the understanding of ankle fracture as well as increase opportunities for follow-up research and aid clinical decision-making.     

Activity-related features of synapse morphology: A study of endbulbs of Held

The myelinated fibers of the auditory nerve can be divided into two separate populations on the basis of sensitivity to sound, average levels of spike activity, and central branching patterns. The synaptic endings of these populations were investigated for the presence of structural specializations that might correlate with levels of neural activity. We applied intracellular recording and staining methods in cats to analyze directly the relationship between spike activity and the structure of synapses using endbulbs of Held, the large synaptic endings in the anteroventral cochlear nucleus. Endbulbs from fibers having low or high levels of activity were examined and compared using light and electron microscopic methods. All endbulbs exhibited relatively large but incomplete coverage by one-to-several lamellae of glial processes. Endbulbs of high activity fibers were large and contained larger mitochondria than endbulbs of low activity fibers. Furthermore, the synapses of high activity endbulbs were on average smaller but more numerous, possessed greater numbers of associated synaptic vesicles, and exhibited greater curvature of their postsynaptic densities. These structural features are hypothesized to reflect specializations that optimize synaptic transmission. © 1996 Wiley-Liss, Inc.     

The role of dysphoric mood and gender in interpersonal responses to nondysphoric others

There now exists a sizeable body of research on interpersonal responses to dysphoric individuals, yet relatively few studies have addressed responses of dysphoric individuals toward others. This study compared responses of dysphoric and nondysphoric individuals toward a nondysphoric person within same-sex and opposite-sex dyads. Dysphoric and nondysphoric subjects did not differ in their desire for future interaction with their interactional partner. Dysphoric subjects reported a greater reduction in feelings of sadness, hostility, and impatience following the interaction, and among dysphoric subjects, those who interacted with a female reported a greater decrease in anxiety than did those who interacted with a male. Dysphoric subjects also perceived their partners to act in a more dysphoric fashion than did nondysphoric subjects. © 1996 John Wiley & Sons, Inc.     

An update on pityrosporum folliculitis in Singapore from a single tertiary care dermatological centre

INTRODUCTIONPityrosporum folliculitis (PF) is a common skin condition that can be easily misdiagnosed, especially by non-dermatologists. While the initial diagnosis is often made clinically, skin microscopy may help to confirm the same. However, there is scant literature regarding the clinical epidemiology of PF. To our knowledge, in Singapore, only one prior epidemiological study was performed in 1987. Through the present study, we aimed to provide an update regarding the epidemiology, diagnosis and treatment of patients with PF in Singapore.METHODSWe performed a retrospective review of patients with clinical presentations compatible with PF who presented to the dermatology clinic at the National University Hospital, Singapore, between 1 January 2011 and 31 December 2015. The medical records of patients identified as having clinical presentations that resembled PF were reviewed via written and electronic databases. Information regarding the demographics and clinical presentation of the patients was collected.RESULTSOf the 375 patients identified, 214 (57.1%) were confirmed as having PF based on Gram-stain microscopy. Most (35.0%) of these 214 patients were aged between 21 and 30 years, with a male-to-female ratio of 3:1. The lesions predominantly occurred on the trunk and the back. The majority of patients presented with symptoms that lasted more than one month. 128 (59.8%) patients received oral antifungal treatment, whereas 82 (38.3%) patients were treated with topical antifungal treatment alone.CONCLUSIONA typical Singapore patient with PF is a young man aged 21–30 years, with erythematous follicular papules or pustules over the trunk and the back.     

Singapore Paediatric Resuscitation Guidelines 2021

We present the 2021 Singapore Paediatric Resuscitation Guidelines. The International Liaison Committee on Resuscitation’s Pediatric Taskforce Consensus Statements on Science and Treatment Recommendations, which was published in October 2020, and the updated resuscitation guidelines from the American Heart Association and European Resuscitation Council, were reviewed and discussed by the committee. These recommendations were derived after deliberation of peer-reviewed evidence updates on paediatric resuscitation and took into consideration the local setting and clinical practice.