Noninvasive Versus Invasive Doppler Renal Blood Velocity and Flow Measurements

We compared simultaneous noninvasive and invasive determinations of blood velocity and flow in the renal arteries of 5 mongrel dogs. Noninvasive measurements of blood velocity spectra (?FN) were made using an ultrasonic echo-Doppler duplex scanner. Vessel diameters (DN) and Doppler angles (?N) were measured from sector images of the renal artery. Invasive measurements of blood velocity spectra (?F1) were made using a catheter Doppler velocimeter. Vessel lumen diameter (D1) and Doppler angle (?1) were measured angiographically. Using the Doppler and continuity equations, temporal mean blood velocities (VN, V1) and flows (QN, Q1) of five cardiac cycles were calculated. The ranges of velocity (8-48 cm/s) and flow (40-380 ml/min) were varied by pharmacological intervention. Standard linear regressions (n = 33) were Results suggest that simultaneous noninvasive echo-Doppler and invasive catheter Doppler measurements of canine renal artery blood velocity and flow correlate significantly. Nevertheless, large standard errors of the estimates exist which suggest that important systematic and experimental errors are present in both methods.     

Gamma Irradiation for Inactivation of C. parvum, E. coli, and Coliphage MS-2

Wastewater and drinking water disinfection are typically achieved via chlorination, ozonation, or UV irradiation. However, there has been increased interest in recent years in alternative disinfectants. This interest came about primarily as a result of concerns over the toxicological effects of disinfection by-products created by conventional disinfection processes and the resistance of some recalcitrant microorganisms to these disinfectants. The work reported herein represents an investigation of the effect of an alternative disinfectant, gamma radiation, on the viability of three important waterborne microorganisms. Escherichia coli, coliphage MS-2, and Cryptosporidium parvum were chosen for this investigation as representative bacterial, viral, and protozoan microorganisms, respectively. A 60Co irradiator was used to expose test microorganisms to a controlled radiation dose. Experiments were performed for each of the test microorganisms to evaluate the effect of dissolved oxygen concentration and carbonate alkalinity on inactivation efficiency. For each microorganism, a strong effect of dissolved oxygen was observed, regardless of alkalinity. A subtle effect of alkalinity was observed for E. coli and coliphage MS-2, but only in air-saturated solutions. No significant alkalinity effect was observed for Cryptosporidium parvum. Inactivation kinetics were modeled for E. coli and coliphage MS-2 using single-target theory to calculate an inactivation rate constant. Multitarget theory was used to represent the inactivation response of Cryptosporidium parvum. The inactivation models based on target theory were found to provide suitable representations of experimental observations.     

SOME PHYSICAL PROPERTIES OF ARTIFICIAL ALUMINOUS ABRASIVES1

Specimens representing six different bond compositions in soft, medium, and hard grades of artificial aluminous grinding wheels were tested for various physical properties such as hardness, elasticity, expansion, mechanical endurance, impact strength, etc. It was found that the expansion of present commercial grinding wheels and abrasive bonds is much less than that of artificial corundum. The strength of the wheels increases greatly with increasing percentages of bond. The methods of making the various physical determinations are given along with their interpretation.     

Synthesis and Biological Evaluation of Novel Epothilone B Side Chain Analogues

The design, synthesis, and biological evaluation of a series of epothilone analogues with novel side chains equipped with an amino group are described. Their design facilitates potential conjugation to selective drug delivery systems such as antibodies. Their synthesis proceeded efficiently via Stille coupling of a readily available vinyl iodide and heterocyclic stannanes. Cytotoxicity studies and tubulin binding assays revealed two of these analogues to be more potent than epothilones A–D and the anticancer agent ixabepilone, currently in clinical use.     

Fusion intermediates of HIV-1 gp41 as targets for antibody production: design, synthesis, and HR1-HR2 complex purification and characterization of generated antibodies

The objective of this project was to study the interaction between HR1 and HR2, the stability of the complex formed, and to characterize the antibodies produced against monomeric HR1 and HR2 peptides as well as the HR1-HR2 complex. In this work, HR1 was mimicked by peptide N36, and HR2 was mimicked by peptide C34L and its analogues C34M2, C34M3, and C34D. Whereas C34M2 and C34M3 are partially composed of D-amino acids, C34D has same sequence as C34L, but is assembled entirely of D-amino acids. Using CD analysis, SPR assays, and gel filtration chromatography, we demonstrate the physical interaction between N36 and C34L and its analogues C34M2 and C34M3, but not C34D. We show that the HR1-HR2 complex is formed rapidly (<1?min) and remains stable, as demonstrated by its inability, in contrast to each free peptide, to inhibit the formation of syncytia. To generate antibodies with predetermined specificity against the transiently exposed intermediate that corresponds to the six-helix bundle structure, purified preformed HR1-HR2 complex was used, in parallel with monomeric HR1 and HR2 peptides, as immunogens in mice. Although the produced antibodies recognize total HIV-1 envelope glycoproteins in ELISA, they are unable to neutralize HIV-1-mediated fusion at 37?°C. However, if the incubation with these antibodies is carried out at 27?°C, a temperature that allows stabilization of the transient intermediate complex, anti-peptide antibodies are able to bind their corresponding domains in HeLa cells expressing HIV-1 gp41 in co-culture with HeLa CD4-CCR5/CXCR4 during the dynamic mechanism of membrane fusion. In agreement with the latter results, these antibodies, if previously incubated for 2?h at 27?°C, are able to strongly neutralize HIV-1 entry by membrane fusion, as shown by their ability to block the formation of syncytia.     

Revisiting the Hydraulics of the Aznalcóllar Mine Disaster

The Aznalcóllar tailings pond failure (1998) is regarded as one of the severe ecological mine disasters ever reported. The spill of the mine tailings affected more than 60 km of the Agrio and Guadiamar rivers and caused major environmental damage. Despite the event being well-documented with more than 400 scientific publications, including two special issues and two reviews, several hydraulic uncertainties and inconsistencies remain. This paper conducts a state-of-the-art review of the most relevant hydraulic aspects of the mine disaster. It addresses the pond and fluid characteristics, the break type, the breaking time, the flow propagation, the volume potentially stored and subsequently spilled, area dimensions affected by the spill, and the morphological changes generated in the river and riverbanks caused by the spill, and later on by the restoration activities. Several discrepancies and plenty of controversial data have been unearthed that may affect general understanding of the event. In addition, new data is introduced and analysed applying photointerpretation and digital terrain analysis techniques, aiming to derive in essential hydraulic parameters. The most important findings are that the spill could have had a volume about 11.5 hm³, affecting about 86.7 km of river length, twice the most referenced values in the literature, and that applied restoration activities have substantially modified the hydro-sedimentary processes of the affected system. Additionally, a first video observation-based classification reveals that the fluid behaved more like a highly concentrated sediment-laden flow than like a mud flow.

     

Robust deflated canonical correlation analysis via feature factoring for multi-view image classification

Multimedia Tools and Applications - Canonical Correlation Analysis (CCA) and its kernel versions (KCCA) are well-known techniques adopted in feature representation and classification for images....     

Enthalpy- versus Entropy-Driven Molecular Recognition in the Era of Biologics

Our laboratory has recently identified two nanobodies (small antibodies produced by camelids)—Nb1 and Nb6—that bind efficiently to epithelial growth factor (EGF) and inhibit its ability to activate its receptor (EGFR). Because of the relevance of the EGF/EGFR axis as a target in oncology, these new nanobodies have promising therapeutic potential. This article, however, is focused on another feature of these nanobodies: their distinct thermodynamic signatures. Nb1 binds to EGF through an entropy-driven mechanism whereas Nb6 binds to this factor under enthalpic control. We discuss the advantages and disadvantages of each mechanism in the contexts of traditional medical chemistry (small-molecule drugs) and also of biological drugs. In this latter case, the implications in terms of selectivity are far from being clearly established and further experimental data are required. Their monomeric natures, high stability, and ease of recombinant production make nanobodies ideally suited for thermodynamic studies. Moreover, nanobodies, thanks to their simpler structures in comparison with conventional antibodies, might provide better understanding of the structural basis of the thermodynamic parameters of antigen recognition.