The Relation between Calcium Sequestering Capacity and Oxidation Degree of Dicarboxy-Starch and Dicarboxy-Inulin

The objective of this study was to establish the relation between the calcium sequestering capacity (SC) of dicarboxy-starch and that of dicarboxy-inulin, and the oxidation degree of these products. An S-type curve is obtained when plotting the SC of oxidized starch versus the degree of oxidation. By contrast the sequestering capacity of dicarboxy-inulin increases linearly with the degree of oxidation. The difference in behaviour of these materials can be attributed to the fact that upon starch oxidation the favourable oxydiacetate structure is obtained only after substantial conversion, whereas in inulin this structure is obtained immediately and is present in each oxidized fructose unit.     

The role of prostaglandin E2 and nitric oxide in cell death in J774 murine macrophages

We investigated the role of prostaglandin E2 (PGE2) and its interactions with nitric oxide (NO) on cell death and NO-mediated cytotoxicity in the murine macrophage cell line J774. Stimulation of the J774 cells with lipopolysaccharide together with interferon-gamma resulted in a dose-dependent cytotoxicity and production of PGE2 and NO, measured as nitrite. Our results showed a linear correlation between PGE2 release and cytotoxicity. The cyclooxygenase (COX) inhibitor indomethacin completely inhibited PGE2 biosynthesis, without affecting NO production or cell death. This supports previous reports suggesting that overproduction of endogenous PGE2 is mainly the consequence of cell death and does not cause it. In contrast, the NO synthase inhibitor N(omega)-monomethyl-L-arginine (L-NMMA) gave a significant, though incomplete suppression of NO release and cell death. This points to the presence of other cytotoxic factors besides NO. To evaluate the toxic effect solely due to NO, macrophages were exposed to the NO donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP). Incubation with SNAP also resulted in a concentration-dependent cell injury and PGE2 production. When exogenously added, PGE2 protected against SNAP-mediated cytotoxicity and simultaneously increased PGE2 release into the medium, without inducing COX-2. The cytoprotection and the stimulation of PGE2 release were both reversed by indomethacin. In conclusion, PGE2 biosynthesis may represent a mechanism by which inflammatory macrophages protect themselves against the cytotoxic effects of NO.     

Increased globotriaosylceramide in familial dysautonomia

Familial Dysautonomia (FD) is an autosomal recessive disease of unknown etiology, occurring primarily in Ashkenazi Jews. Patients are neurologically impaired, with deficits primarily in autonomic and sensory functions. The biochemical and genetic defects have remained elusive, precluding carrier detection and prenatal diagnosis. High-performance liquid chromatography data indicated up to a threefold increase in the neutral glycosphingolipid globotriaosylceramide in Dysautonomic fibroblasts and lymphoblasts. Total ganglioside values, measured by colorimetric, fluorometric or specific sodium borohydride incorporation, were decreased. Affected fibroblasts exhibited a range of pleomorphic phenotypes, such that the usual swirl-like confluent growth pattern of normal fibroblasts was distorted to varying degrees, suggesting abnormalities in the FD plasma membrane, possibly affecting cell-cell contacts. The glycosphingolipid increase could not be accounted for on the basis of markedly decreased α-galactosidase activity, as in Fabry's disease, where patients also display decreased autonomic function.     

Formulation for chemical EOR: Development and evaluation of an ASP formulation In customer field conditions

Alkali surfactant polymer (ASP) flooding is an enhanced oil recovery (EOR) technology with an impressive potential for increasing incremental oil production from conventional hydrocarbon bearing reservoirs. A challenge to ASP application is the complexity of determining an effective formulation, typically requiring extensive laboratory screening of nearly countless combinations of surfactants and cosolvents. This paper focuses on demonstrating the utility of the hydrophilic–lipophilic deviation (HLD) concept for EOR application to simplify surfactant formulation workstreams seeking an economically viable ASP formulation for field application. In describing work performed for EOR application of ASP under customer conditions using crude oil, the discussion covers the initial evaluation of the promising surfactant formulation (interfacial tension and solubility), the improvement upon the formulation via HLD principles, and the evaluation of the improved surfactant formulation (coreflood studies). The final ASP formulation identified consisted of a 9 to 1 mixture of alkyl propoxy sulfate sodium salt (APS) to alkyl ethoxy sulfate sodium salt (AES) totaling 2000 ppm active surfactant content, 2.0 wt% Na₂CO₃, and 3000 ppm polyacrylamide polymer (all commercially available products). This formulation had ultra-low interfacial tension and favorable mixing behavior under reservoir conditions. In coreflood studies, the final formulation reproducibly achieved cumulative oil recovery of 96.4%–98.5% of original oil in place with only 0.3 PV of ASP injection with a chase alkali polymer injection.     

PREDICTION OF PINEAPPLE SORPTION ISOTHERMS USING THE ROSS EQUATION

ABSTRACT

A mathematical prediction of pineapple sorption isotherms was developed using Ross, Norrish and Henderson equations. The prediction considered to have the pineapple average composition oflhe main solutes: sucrose, glucose, fructose, citric acid, malic acid, NaCI, KC1 and cellulose as non-solute. Water activity of individual sugars and organic acids was obtained by Norrish's equation and for the two salts by Raoult's Law. Solute solubility at different temperatures was taken into account. Predicted isotherms were compared with the experimental isotherms obtained in laboratory at 30, 35, 40 and 45° C and with the isotherms reported in literature at 30 and 45° C. The generalized correlation coefficients ( r² ) between predicted and experimental isotherms were in the range of 0.8 - 0.98.     

Small Molecule Inhibitors of AI-2 Signaling in Bacteria: State-of-the-Art and Future Perspectives for Anti-Quorum Sensing Agents

Bacteria respond to different small molecules that are produced by other neighboring bacteria. These molecules, called autoinducers, are classified as intraspecies (i.e., molecules produced and perceived by the same bacterial species) or interspecies (molecules that are produced and sensed between different bacterial species). AI-2 has been proposed as an interspecies autoinducer and has been shown to regulate different bacterial physiology as well as affect virulence factor production and biofilm formation in some bacteria, including bacteria of clinical relevance. Several groups have embarked on the development of small molecules that could be used to perturb AI-2 signaling in bacteria, with the ultimate goal that these molecules could be used to inhibit bacterial virulence and biofilm formation. Additionally, these molecules have the potential to be used in synthetic biology applications whereby these small molecules are used as inputs to switch on and off AI-2 receptors. In this review, we highlight the state-of-the-art in the development of small molecules that perturb AI-2 signaling in bacteria and offer our perspective on the future development and applications of these classes of molecules.     

Molecularly Targeted Agents as Radiosensitizers in Cancer Therapy—Focus on Prostate Cancer

As our understanding of the molecular pathways driving tumorigenesis improves and more druggable targets are identified, we have witnessed a concomitant increase in the development and production of novel molecularly targeted agents. Radiotherapy is commonly used in the treatment of various malignancies with a prominent role in the care of prostate cancer patients, and efforts to improve the therapeutic ratio of radiation by technologic and pharmacologic means have led to important advances in cancer care. One promising approach is to combine molecularly targeted systemic agents with radiotherapy to improve tumor response rates and likelihood of durable control. This review first explores the limitations of preclinical studies as well as barriers to successful implementation of clinical trials with radiosensitizers. Special considerations related to and recommendations for the design of preclinical studies and clinical trials involving molecularly targeted agents combined with radiotherapy are provided. We then apply these concepts by reviewing a representative set of targeted therapies that show promise as radiosensitizers in the treatment of prostate cancer.     

Wear resistance glass-ceramics with a gahnite phase obtained in CaO-MgO-ZnO-Al2O3-B2O3-SiO2 system

The thermal conditions for obtaining the glass-ceramic material of Al_0.107B_0.374Mg_0.043Zn_0.282Ca_0.100Si_0.927O₃ with a crystalline phase in the form of gahnite (ZnAl₂O₄) were specified. The activation energy E_a and the Avrami parameter n for the crystallisation process were determined with the non-isothermal DTA procedure. The maximum temperatures of crystallisation of phases, depending on the rate of heating, ranged between 800-840 °C for willemite and 870-915 °C for gahnite. The homogeneous crystalline spinel phase was obtained by heat treatment above 1000 °C. Precipitation solely of a ghanite phase from glass-ceramic causes a relative increase in its fracture toughness and wear resistance compared to the two-phase materials, i.e., K_IC = 2.12-1.65 MPam^1/2 and w_s = 0.21 × 10⁻⁴ mm³/Nm to w_s = 1.43 × 10⁻⁴ mm³/Nm.     

Activity-based profiling of retaining β-glucosidases: a comparative study

Activity-based protein profiling (ABPP) is a versatile strategy to report on enzyme activity in vitro, in situ, and in vivo. The development and use of ABPP tools and techniques has met with considerable success in monitoring physiological processes involving esterases and proteases. Activity-based profiling of glycosidases, on the other hand, has proven more difficult, and to date no broad-spectrum glycosidase activity-based probes (ABPs) have been reported. In a comparative study, we investigated both 2-deoxy-2-fluoroglycosides and cyclitol epoxides for their utility as a starting point towards retaining β-glucosidase ABP. We also investigated the merits of direct labeling and two-step bio-orthogonal labeling in reporting on glucosidase activity under various conditions. Our results demonstrate that 1) in general cyclitol epoxides are the superior glucosidase ABPs, 2) that direct labeling is the more efficient approach but it hinges on the ability of the glucosidase to be accommodated in the active site of the reporter (BODIPY) entity, and 3) that two-step bio-orthogonal labeling can be achieved on isolated enzymes but translating this protocol to cell extracts requires more investigation.