1,067 research outputs found
Duodenal enteroglucagonoma revealed by differential comparison of serum and tissue glucagon reactivity with Siemens' Double Glucagon Antibody and DakoCytomation's Polyclonal Rabbit Anti-Human Glucagon: a case report
<p>Abstract</p> <p>Introduction</p> <p>This case report demonstrates that the differential immunohistochemical reactivities of Siemens' <it>Double Antibody Glucagon </it>compared to DakoCytomation's <it>Polyclonal Rabbit Anti-Human Glucagon </it>allow for pathologic distinction of enteral versus pancreatic glucagonoma.</p> <p>Case presentation</p> <p>A 64-year-old Caucasian man was diagnosed with a duodenal enteroglucagonoma following presentation with obstructive jaundice. He had a low serum glucagon level using Siemens' <it>Double Antibody Glucagon</it>, a clinical syndrome consistent with glucagon hypersecretion. A periampullary mass biopsy proved to be a neuroendocrine tumor, with positive immunohistochemical reactivity to DakoCytomation's <it>Polyclonal Rabbit Anti-Human Glucagon</it>.</p> <p>Conclusions</p> <p>Differential comparison of the immunohistochemical reactivities of Siemens' <it>Double Antibody Glucagon </it>and DakoCytomation's <it>Polyclonal Rabbit Anti-Human Glucagon </it>discerns enteroglucagon from pancreatic glucagon.</p
Pseudo-aneurysm of the anterior tibial artery, a rare cause of ankle swelling following a sports injury
BACKGROUND: Ankle pain and swelling following sports injuries are common presenting complaints to the accident and emergency department. Frequently these are diagnosed as musculoskeletal injuries, even when no definitive cause is found. Vascular injuries following trauma are uncommon and are an extremely rare cause of ankle swelling and pain. These injuries may however be limb threatening and are important to diagnose early, in order that appropriate treatment can be delivered. We highlight the steps to diagnosis of these injuries, and methods of managing these injuries. It is important for clinicians to be aware of the potential for this injury in patients with seemingly innocuous trauma from sports injuries, who have significant ankle pain and swelling. CASE PRESENTATION: A young, professional sportsman presented with a swollen, painful ankle after an innocuous hyper-plantar flexion injury whilst playing football, which was initially diagnosed as a ligamentous injury after no bony injury was revealed on X-Ray. He returned 2 days later with a large ulcer at the lateral malleolus and further investigation by duplex ultrasound and transfemoral arteriogram revealed a Pseudo-Aneurysm of the Anterior Tibial Artery. This was initially managed with percutaneous injection of thrombin, and later open surgery to ligate the feeding vessel. The patient recovered fully and was able to return to recreational sport. CONCLUSION: Vascular injuries remain a rare cause of ankle pain and swelling following sports injuries, however it is important to consider these injuries when no definite musculo-skeletal cause is found. Ultrasound duplex and Transfemoral arteriogram are appropriate, sensitive modalities for investigation, and may allow novel treatment to be directed percutaneously. Early diagnosis and intervention are essential for the successful outcome in these patients
Energy expenditure compared to physical activity measured by accelerometry and self-report in adolescents: a validation study
Background
Physical inactivity is responsible for 5.3 million deaths annually worldwide. To measure physical activity energy expenditure, the doubly labeled water (DLW) method is the gold standard. However, questionnaires and accelerometry are more widely used. We compared physical activity measured by accelerometer and questionnaire against total (TEE) and physical activity energy expenditure (PAEE) estimated by DLW.
Methods
TEE, PAEE (TEE minus resting energy expenditure) and body composition were measured using the DLW technique in 25 adolescents (16 girls) aged 13 years living in Pelotas, Brazil. Physical activity was assessed using the Actigraph accelerometer and by self-report. Physical activity data from accelerometry and self-report were tested against energy expenditure data derived from the DLW method. Further, tests were done to assess the ability of moderate-to-vigorous intensity physical activity (MVPA) to predict variability in TEE and to what extent adjustment for fat and fat-free mass predicted the variability in TEE.
Results
TEE varied from 1,265 to 4,143 kcal/day. It was positively correlated with physical activity (counts) estimated by accelerometry (rho = 0.57; p = 0.003) and with minutes per week of physical activity by questionnaire (rho = 0.41; p = 0.04). An increase of 10 minutes per day in moderate-to-vigorous intensity physical activity (MVPA) relates to an increase in TEE of 141 kcal/day. PAEE was positively correlated with accelerometry (rho = 0.64; p = 0.007), but not with minutes per week of physical activity estimated by questionnaire (rho = 0.30; p = 0.15). Physical activity by accelerometry explained 31% of the vssariability in TEE. By incorporating fat and fat-free mass in the model, we were able to explain 58% of the variability in TEE.
Conclusion
Objectively measured physical activity significantly contributes to the explained variance in both TEE and PAEE in Brazilian youth. Independently, body composition also explains variance in TEE, and should ideally be taken into account when using accelerometry to predict energy expenditure values
Pinning quantum phase transition for a Luttinger liquid of strongly interacting bosons
One of the most remarkable results of quantum mechanics is the fact that
many-body quantum systems may exhibit phase transitions even at zero
temperature. Quantum fluctuations, deeply rooted in Heisenberg's uncertainty
principle, and not thermal fluctuations, drive the system from one phase to
another. Typically, the relative strength of two competing terms in the
system's Hamiltonian is changed across a finite critical value. A well-known
example is the Mott-Hubbard quantum phase transition from a superfluid to an
insulating phase, which has been observed for weakly interacting bosonic atomic
gases. However, for strongly interacting quantum systems confined to
lower-dimensional geometry a novel type of quantum phase transition may be
induced for which an arbitrarily weak perturbation to the Hamiltonian is
sufficient to drive the transition. Here, for a one-dimensional (1D) quantum
gas of bosonic caesium atoms with tunable interactions, we observe the
commensurate-incommensurate quantum phase transition from a superfluid
Luttinger liquid to a Mott-insulator. For sufficiently strong interactions, the
transition is induced by adding an arbitrarily weak optical lattice
commensurate with the atomic granularity, which leads to immediate pinning of
the atoms. We map out the phase diagram and find that our measurements in the
strongly interacting regime agree well with a quantum field description based
on the exactly solvable sine-Gordon model. We trace the phase boundary all the
way to the weakly interacting regime where we find good agreement with the
predictions of the 1D Bose-Hubbard model. Our results open up the experimental
study of quantum phase transitions, criticality, and transport phenomena beyond
Hubbard-type models in the context of ultracold gases
Investigating the structure of biomass-derived non-graphitizing mesoporous carbons by electron energy loss spectroscopy in the transmission electron microscope and X-ray photoelectron spectroscopy
We have investigated the microstructure and bonding of two biomass-based porous carbon chromatographic stationary phase materials (alginic acid-derived Starbon® and calcium alginate-derived mesoporous carbon spheres (AMCS) and a commercial porous graphitic carbon (PGC), using high resolution transmission electron microscopy, electron energy loss spectroscopy (EELS), N2 porosimetry and X-ray photoelectron spectroscopy (XPS). The planar carbon sp 2-content of all three material types is similar to that of traditional nongraphitizing carbon although, both biomass-based carbon types contain a greater percentage of fullerene character (i.e. curved graphene sheets) than a non-graphitizing carbon pyrolyzed at the same temperature. This is thought to arise during the pyrolytic breakdown of hexauronic acid residues into C5 intermediates. Energy dispersive X-ray and XPS analysis reveals a homogeneous distribution of calcium in the AMCS and a calcium catalysis mechanism is discussed. That both Starbon® and AMCS, with high-fullerene character, show chromatographic properties similar to those of a commercial PGC material with extended graphitic stacks, suggests that, for separations at the molecular level, curved fullerene- like and planar graphitic sheets are equivalent in PGC chromatography. In addition, variation in the number of graphitic layers suggests that stack depth has minimal effect on the retention mechanism in PGC chromatography
Use of mixed methods designs in substance research: a methodological necessity in Nigeria
The utility of mixed methods (qualitative and quantitative) is becoming increasingly accepted in health sciences, but substance studies are yet to substantially benefit from such utilities. While there is a growing number of mixed methods alcohol articles concerning developed countries, developing nations are yet to embrace this method. In the Nigerian context, the importance of mixed methods research is yet to be acknowledged. This article therefore, draws on alcohol studies to argue that mixed methods designs will better equip scholars to understand, explore, describe and explain why alcohol consumption and its related problems are increasing in Nigeria. It argues that as motives for consuming alcohol in contemporary Nigeria are multiple, complex and evolving, mixed method approaches that provide multiple pathways for proffering solutions to problems should be embraced
Using metrics and sustainability considerations to evaluate the use of bio-based and non-renewable Brønsted acidic ionic liquids to catalyse Fischer esterification reactions
Background Ionic liquids have found uses in many applications, one of which is the joint solvation and catalysis of chemical transformations. Suitable Brønsted acidic ionic liquids can be formed by combining lactams with sulphonic acids. This work weighs up the relative benefits and disadvantages of applying these Brønsted acidic ionic liquid catalysts in esterifications through a series of comparisons using green chemistry metrics. Results A new bio-based ionic liquid was synthesised from N-methyl pyrrolidinone and p-cymenesulphonic acid, and tested as a catalyst in three Fischer esterifications under different conditions. An evaluation of the performance of this Brønsted acidic ionic liquid was made through the comparison to other ionic liquid catalysts as well as conventional homogeneous Brønsted acids. Conclusion Extending the argument to feedstock security as well as mass utilisation, ultimately in most instances traditional mineral acids appear to be the most sensible option for Brønsted acid esterification catalysts. Ester yields obtained from Brønsted acidic ionic liquid catalysed procedures were modest. This calls into question the diversity of research exploring esterification catalysis and the role of ionic liquids in esterifications
Evaluation Method, Dataset Size or Dataset Content: How to Evaluate Algorithms for Image Matching?
Most vision papers have to include some evaluation work in order to demonstrate that the algorithm proposed is an improvement on existing ones. Generally, these evaluation results are presented in tabular or graphical forms. Neither of these is ideal because there is no indication as to whether any performance differences are statistically significant. Moreover, the size and nature of the dataset used for evaluation will obviously have a bearing on the results, and neither of these factors are usually discussed. This paper evaluates the effectiveness of commonly used performance characterization metrics for image feature detection and description for matching problems and explores the use of statistical tests such as McNemar’s test and ANOVA as better alternatives
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