Visible transparent, UV-blocking polymer nanocomposite films containing nano-sized organic-LDH (Layered Double Hydroxide) hybrid

A nano-sized Mg2Al layered double hydroxide (LDH) was used for encapsulating an organic UV absorber, 2-hydroxy-4- methoxybenzeophenone-5-sulfonic acid (HMBS), to produce HMBS@LDH hybrid nano-platelets. Upon dispersing this organic-inorganic hybrid LDH into ethylene-vinyl alcohol copolymer (EVOH) for film casting, a thin polymer
nanocomposite film that is UV opaque but highly transparent to visible light (higher than 90%) was formed. Thermogravimetry (TG) analysis confirmed that the intercalation of HMBS into LDH considerably increased the thermal stability of HMBS. Such an improvement was attributed to the strong guest-host interaction between the HMBS anions and the LDH layers. Also, the nanocomposite films were flexible and had good mechanical properties.

Direct measurement of surface forces between sapphire crystals in aqueous solutions

Measurements are presented of the electrical double layer and van der Waals forces between the (0001) surfaces of two single-crystal sapphire platelets immersed in an aqueous solution of NaCl at pH values from 6.7 to 11. The results fit the standard Deryaguin-Landau-Verwey-Overbeek (DLVO) theory, with a Hamaker constant of 6.7 × 10−20 J. These are the first measurements made using the Israelachvili surface forces apparatus without mica as a substrate material, and they demonstrate the possibility of using this technique to explore the surface chemistry of a wider range of materials.

Hydrophobic attraction may contribute to aqueous flocculation of clays

SEM observations of low solid content vitrified clay suspensions reveal that clay platelets build porous three-dimensional networks with platelets contacting each other mostly by their edges. To explain this behaviour, which must require long range edge-to-edge (EE) attractive forces, a hydrophobic-like interaction has been proposed. This interaction may be induced by the presence of nano-bubbles existing on the edges of clay crystals which may cause clay particles to flocculate. The following indirect evidence for such hydrophobic behaviour is presented. First, a clay platelet is shown attached to an oil drop by its edge; second, clay flocs were attracted by a vertically placed Teflon strip but not to the hydrophilic mica basal surface; third, a much thicker porous sediment occurred in CO2-saturated water solution compared with vacuum degassed water.

The effect of alternate heating rates during cure on the structure-property relationships of epoxy/MMT clay nanocomposites

This paper investigates the effect of both the mixing technique and heating rate during cure on the dispersion of montmorillonite (MMT) clay in an epoxy resin. The combination of sonication and using a 10. °C/min heating rate during cure was found to facilitate the dispersion of nanoclay in epoxy resin. These processing conditions provided a synergistic effect, making it possible for polymer chains to penetrate in-between clay galleries and detach platelets from their agglomerates. As the degree of dispersion was enhanced, the flexural modulus and strength properties were found to decrease by 15% and 40%, respectively. This is thought to be due to individual platelets fracturing in the nanocomposite. Complementary techniques including X-ray diffraction (XRD), small angle X-ray scattering (SAXS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM) and optical microscopy were essential to fully characterise localised and spatial regions of the clay morphologies.

Immune thrombocytopenic purpura (ITP) and breast cancer. Does adjuvant therapy for breast cancer improve platelet counts in ITP?

Although both breast cancer and immune thrombocytopenic purpura (ITP) are common conditions, the simultaneous coexistence of these two diseases is rare. ITP is an autoimmune disease in which the presence of autoantibodies against platelets results in splenic sequestration and thrombocytopenia that may be associated with lymphoid neoplasms [1]. Except for an observational case series of 10 patients [2], only a few individual case reports of ITP coinciding with breast cancer have been reported [3–8]. We are reporting two cases with simultaneous confirmed ITP and breast cancer. The platelet counts in both women have improved during adjuvant breast cancer chemotherapy.

Emerging engineered magnetic nanoparticulate probes for molecular MRI of atherosclerosis : how far have we come?

Atherosclerosis is a chronic, progressive, immunoinflammatory disease of the large and medium-sized arteries, and a major cause of cardiovascular diseases. Atherosclerosis often progresses silently for decades until the occurrence of a major catastrophic clinical event such as myocardial infarction, cardiac arrest and stroke. The main challenge in the diagnosis and management of atherosclerosis is to develop a safe, noninvasive technique that is accurate and reproducible, which can detect the biologically active high-risk vulnerable plaques (with ongoing active inflammation, angiogenesis and apoptosis) before the occurrence of an acute clinical event. This Journal Article reviews the events involved in the pathogenesis of atherosclerosis in light of recently advanced understanding of the molecular pathogenesis of the disease. Next, we elaborate on the interesting developments in molecular MRI, by describing the recently engineered magnetic nanoparticulate probes targeting clinically promising molecular and cellular players/processes, involved in early atherosclerotic lesion formation to plaque rupture and erosion.

Crystalline Structures and α → β and γ polymorphs transformation induced by nanoclay in PVDF-based nanocomposite

Poly(vinylidene fluoride) (PVDF) nanocomposites were prepared by melt-mixing. The dispersion of clay platelets and rheology of nanocomposites were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and rheometric mechanical spectrometer (RMS). The transformation of α to β and γ phase in PVDF was induced by the addition of nanoclay and subsequently the isothermal crystallization kinetics of neat PVDF and its nanocomposite have been investigated. The interaction between clay nanofillers and PVDF macromolecular chains induced the change of conformation from trans-gauche to all-trans crystal structure in PVDF segment. The isothermal crystallization of PVDF/clay nanocomposites was carried out by Differential Scanning Calorimetry (DSC) technique. The influence of clay platelets on nucleation crystallization rate and Avrami exponent were studied. PVDF/clay nanocomposite showed higher crystallization rate indicating that nanoclay has acted as an effective nucleation agent. This nucleation effect of nanoclay increased the Avrami exponent and decreased the degree of crystallinity. © 2014 World Scientific Publishing Company.

Augmented platelet calcium uptake in response to serotonin stimulation in patients with major depression measured using Mn2+ influx and 45Ca2+ uptake.

There is an augmented platelet intracellular calcium response to serotonin stimulation in major depression. The role that calcium influx has in this process is not known. The objective of this study was to determine platelet calcium influx in response to serotonin by two methods, Mn2+ influx and 45Ca2+ uptake, in order to observe if the uptake response to serotonin was augmented in major depression by comparing the response to normal controls. The use of the two methods of calcium influx showed that serotonin stimulates calcium uptake into platelets. Furthermore, patients with major depression have significantly augmented platelet calcium uptake in response to serotonin. The interesting finding was that calcium uptake into platelets is biphasic, occurring immediately and after five minutes. These results may support the two pool model for calcium oscillations within cells whereby extracellular calcium is needed for intracellular calcium release, and for replenishment of depleted stores once intracellular calcium is released.

Changes in the platelet intracellular calcium response to serotonin in patients with major depression treated with electroconvulsive therapy: state or trait marker status.

Platelet serotonin type 2A receptor (5-HT2A) sensitivity changes have previously been documented in depression, although it is unclear if this represents a stable trait marker of the illness, or whether it represents an acute state marker of depression that would change with treatment. Electroconvulsive therapy (ECT) may be a useful intervention to separate out trait and state marker status avoiding the potential confounding effects of pharmacotherapy on receptor function. Using spectrofluorometry, the platelet 5HT2A, receptor sensitivity as reflected by the intracellular calcium response to serotonin stimulation, was measured every week in patients suffering from major depression and undergoing ECT. There was a significant drop in the platelet response to serotonin stimulation over a course of ECT, with an associated progressive decrease in Hamilton Rating Scale of Depression (HAM-D) scores. This may suggest either decreased sensitivity of platelet 5HT2A receptors as a mechanism of action of ECT, or changes in second messengers such as the inositide phospholipid system. This suggests that the enhanced sensitivity of platelet 5HT2A receptors may be a state marker of major depression.

Venous thromboembolism and underutilisation of anticoagulant thromboprophylaxis in hospitalised patients with inflammatory bowel disease

Background: Venous thromboembolism (VTE) is a well-recognised extra-intestinal manifestation of inflammatory bowel disease (IBD). Despite the widespread support for anticoagulant prophylaxis in hospitalised IBD patients, the utilisation and efficacy in clinical practice are unknown. Aims: The aim of this study was to assess the prevalence and clinical features of VTE among hospitalised IBD patients and ascertain whether appropriate thromboprophylaxis had been administered. Methods: All patients with a discharge diagnosis of Crohn disease or ulcerative colitis and VTE were retrospectively identified using International Classification of Diseases, tenth revision codes from medical records at our institution from July 1998 to December 2009. Medical records were then reviewed for clinical history and utilisation of thromboprophylaxis. Statistical analysis was performed by Mann-Whitney test and either χ2 tests or Fisher's exact tests. Results: Twenty-nine of 3758 (0.8%) IBD admissions suffered VTE, 13 preadmission and 16 during admission. Of these 29 admissions (in 25 patients), 24% required intensive care unit and 10% died. Of the 16 venous thrombotic events that occurred during an admission, eight (50%) did not receive anticoagulant thromboprophylaxis and eight (50%) occurred despite thromboprophylaxis. Most thromboembolism despite prophylaxis occurred post-intestinal resection (n = 5, 63%). Conclusion: Thromboprophylaxis is underutilised in half of IBD patients suffering VTE. Prescription of thromboprophylaxis for all hospitalised IBD patients, including dual pharmacological and mechanical prophylaxis in postoperative patients, may lead to a reduction in this preventable complication of IBD. © 2014 Royal Australasian College of Physicians.

Dietary sources, current intakes, and nutritional role of omega-3 docosapentaenoic acid

Fish oils and long-chain omega-3 fatty acids are well recognized for their critical role in human diets. Docosapentaenoic acid (DPA, 22:5n-3) has always been a part of healthy nutrition, since infants obtain almost as much DPA as DHA from human milk. Fish oil supplements and ingredients, oily fish, and grass-fed beef can serve as the primary DPA sources for the general population. Although the DPA levels in fish oils are substantially lower than those of EPA and DHA, concentrated DPA products are now becoming commercially available, and DPA-based drugs are under development. Epidemiological studies show that similar to eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids, DPA is linked to various improvements in human health, perhaps owing to its structural similarity to the other two molecules. Studies in mammals, platelets, and cell cultures have demonstrated that DPA reduces platelet aggregation, and improves lipid metabolism, endothelial cell migration, and resolution of chronic inflammation. Further, other in vivo and in vitro studies have shown that DPA can improve neural health. A human supplementation trial with 99.8% pure DPA suggested that it serves as a storage depot for EPA and DHA in the human body. Future randomized controlled human trials with purified DPA will help clarify its effects on human health. They may confirm the available evidence pointing to its nutritional and biological functions, unique or overlapping with those of EPA and DHA.