Influence of the dimensions of spheroniser plate protuberances on the production of pellets by extrusion-spheronisation

This study systematically investigated the influence of the dimensions of square-patterned pyramidal protuberances on a spheronisation plate on pellet yield, size and shape distributions, surface tensile strength and surface morphology was investigated using a 45 wt% microcrystalline cellulose/ water paste. Tests were conducted using four different extrudate diameters (1.0, 1.5, 2.0 and 2.5 mm) generated by screen extrusion and seven plate geometries, including a flat plate as a control, allowing the relative size of extrudate to protuberance feature to be studied. Geometrical analyses of the protuberance shapes provide some insight into the observed differences, with protuberance angle being significant in many cases. Sharper protuberances reduced yield (promoting breakage and attrition) but tended to give narrower size distributions and more uneven pellet surface. Pellet yield for 1 mm extrudates was also subject to losses caused by fragments passing through the 1.0 mm gap between the plate and spheroniser wall. Pellet tensile strength was noticeably greater for 1.0 mm diameter extrudates, which is attributed to the greater extensional strain imparted on the paste during the extrusion step. For some geometries there is an optimal ratio of extrudate to protuberance dimensions

Influence of apical oxygen on the extent of in-plane exchange interaction in cuprate superconductors

In high Tc superconductors the magnetic and electronic properties are determined by the probability that valence electrons virtually jump from site to site in the CuO2 planes, a mechanism opposed by on-site Coulomb repulsion and favored by hopping integrals. The spatial extent of the latter is related to transport properties, including superconductivity, and to the dispersion relation of spin excitations (magnons). Here, for three antiferromagnetic parent compounds (single-layer Bi2Sr0.99La1.1CuO6+delta, double-layer Nd1.2Ba1.8Cu3O6 and infinite-layer CaCuO2) differing by the number of apical atoms, we compare the magnetic spectra measured by resonant inelastic x-ray scattering over a significant portion of the reciprocal space and with unprecedented accuracy. We observe that the absence of apical oxygens increases the in-plane hopping range and, in CaCuO2, it leads to a genuine 3D exchange-bond network. These results establish a corresponding relation between the exchange interactions and the crystal structure, and provide fresh insight into the materials dependence of the superconducting transition temperature.Comment: 9 pages, 4 figures, 1 Table, 42 reference

Perspectives on the Trypanosoma cruzi-host cell receptor interaction

Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets

Visualizing peripheral nerve regeneration by whole mount staining.

Peripheral nerve trauma triggers a well characterised sequence of events both proximal and distal to the site of injury. Axons distal to the injury degenerate, Schwann cells convert to a repair supportive phenotype and macrophages enter the nerve to clear myelin and axonal debris. Following these events, axons must regrow through the distal part of the nerve, re-innervate and finally are re-myelinated by Schwann cells. For nerve crush injuries (axonotmesis), in which the integrity of the nerve is maintained, repair may be relatively effective whereas for nerve transection (neurotmesis) repair will likely be very poor as few axons may be able to cross between the two parts of the severed nerve, across the newly generated nerve bridge, to enter the distal stump and regenerate. Analysing axon growth and the cell-cell interactions that occur following both nerve crush and cut injuries has largely been carried out by staining sections of nerve tissue, but this has the obvious disadvantage that it is not possible to follow the paths of regenerating axons in three dimensions within the nerve trunk or nerve bridge. To try and solve this problem, we describe the development and use of a novel whole mount staining protocol that allows the analysis of axonal regeneration, Schwann cell-axon interaction and re-vascularisation of the repairing nerve following nerve cut and crush injuries

Allopurinol Reduces the Lethality Associated with Acute Renal Failure Induced by Crotalus durissus terrificus Snake Venom: Comparison with Probenecid

In Brazil, among registered snake bites, those by the genus Crotalus originate the highest mortality rate. The rattlesnake Crotalus durissus terrificus is the most frequently implicated in these accidents. The kidney is a particularly vulnerable organ to the venom of this rattlesnake. In fact, the most serious complication of Crotalus snake bite is the renal dysfunction, and among the fatal cases of Crotalus bites in Brazil 5% are patients treated with antivenom. The hyperuricemia has been observed in human accidents with snake venoms, but this parameter has not received any special attention as a relevant factor in the etiology of renal dysfunction caused by these venoms. This study examined the effects of treatments with low-cost and low-risk uricostatic (allopurinol) and uricosuric (probenecid) drugs on the envenomation by C. d. terrificus, showing that allopurinol and probenecid mitigated certain nephrotoxic effects, as well as the survival of envenomed mice was improved through the effects of allopurinol on reduction of oxidative stress and intracellular formation of uric acid. This new knowledge provides consistent evidences linking uric acid with the renal dysfunction induced by rattlesnake bites and that the allopurinol deserves to be clinically evaluated as an approach complementary to anti-snake venom serotherapy

Serum uri acid: neuroprotection in thrombolysis. The Bergen NORSTROKE study

<p>Abstract</p> <p>Background</p> <p>A possible synergic role of serum uric acid (SUA) with thrombolytic therapies is controversial and needs further investigations. We therefore evaluated association of admission SUA with clinical improvement and clinical outcome in patients receiving rt-PA, early admitted patients not receiving rt-PA, and patients admitted after time window for rt-PA.</p> <p>Methods</p> <p>SUA levels were obtained at admission and categorized as low, middle and high, based on 33° and 66° percentile values. Patients were categorized as patients admitted within 3 hours of symptom onset receiving rt-PA (rt-PA group), patients admitted within 3 hours of symptom onset not receiving rt-PA (non-rt-PA group), and patients admitted after time window for rt-PA (late group). Short-term clinical improvement was defined as the difference between NIHSS on admission minus NIHSS day 7. Favorable outcome was defined as mRS 0 - 3 and unfavorable outcome as mRS 4 - 6.</p> <p>Results</p> <p>SUA measurements were available in 1136 patients. Clinical improvement was significantly higher in patients with high SUA levels at admission. After adjustment for possible confounders, SUA level showed a positive correlation with clinical improvement (r = 0.012, 95% CI 0.002-0.022, p = 0.02) and was an independent predictor for favorable stroke outcome (OR 1.004; 95% CI 1.0002-1.009; p = 0.04) only in the rt-PA group.</p> <p>Conclusions</p> <p>SUA may not be neuroprotective alone, but may provide a beneficial effect in patients receiving thrombolysis.</p

Finite element analysis and calculation method of residual flexural capacity of post-fire RC beams

Fire tests and subsequent bending tests of fourreinforced concrete (RC) beamswere performed. Based on these tests, the post-fire performance of RCbeams was further studied using finite element simulation through reasonable selection of suitable thermal and thermodynamic parameters of steel and concrete materials. A thermodynamic model of RC beams with three sides under fire was built using finite element analysis(FEA)software ABAQUS. The FEA model was validated with the results of fire tests. Different factors were taken into account for further parametric studies in fire using the proposed FE model.The results show that the main factors affecting the fire resistance of the beamsare the thickness of the concretecover, reinforcement ratio of longitudinal steel,the fire exposure timeandthe fire exposure sides. Based on the strength reduction formula at high temperature of steel and concrete, animproved section method was proposed to develop a calculation formula to calculate the flexural capacity of RC beams after fire. The theoretical calculation method proposed in this paper shows good agreement with FEA results, which can be used to calculate the flexuralcapacity of RC beams after fire

Schwann cell hamartoma: case report

<p>Abstract</p> <p>Background</p> <p>Colorectal polyps of mesenchymal origin represent a small percentage of gastrointestinal (GI) lesions. Nevertheless, they are encountered with increasing frequency since the widespread adoption of colonoscopy screening.</p> <p>Case presentation</p> <p>We report a case of a small colonic polyp that presented as intramucosal diffuse spindle cell proliferation with a benign cytological appearance, strong and diffuse immunoreactivity for S-100 protein, and pure Schwann cell phenotype. Careful morphological, immunohistochemical and clinical evaluation emphasize the differences from other stromal colonic lesions and distinguish it from schwannoma, a circumscribed benign nerve sheath tumor that rarely arises in the GI tract.</p> <p>Conclusion</p> <p>As recently proposed, this lesion was finally described as mucosal Schwann cell hamartoma.</p

Nucleofection induces non-specific changes in the metabolic activity of transfected cells

Transfection has become an everyday technique widely used for functional studies in living cells. The choice of the particular transfection method is usually determined by its efficiency and toxicity, and possible functional consequences specific to the method used are normally overlooked. We describe here that nucleofection, a method increasingly used because of its convenience and high efficiency, increases the metabolic rate of some cancer cells, which can be misleading when used as a measure of proliferation. Moreover, nucleofection can alter the subcellular expression pattern of the transfected protein. These undesired effects are independent of the transfected nucleic acid, but depend on the particular cell line used. Therefore, the interpretation of functional data using this technology requires further controls and caution