The Mona Lisa identification: Evidence from a computer analysis

A recent computer-aided study identified the model immortalized in Leonardo da Vinci's celebratedMona Lisa to be none other than the artist himself. A follow-up investigation empolying similar techniques identifies the subject of asecond HiddenMona Lisa by the same artist. Analysis of photographic and x-ray images indicates that Leonardo first created a sketch of Isabella, Duchess of Aragon, which he later painted over with theMona Lisa, using himself as the model.     

Archival Appraisal and the Digital Record: Applying Past Tradition for Future Practice

The digital revolution has changed the daily work of archivists. As a result, archivists have refined their analog practices and initiated new ones to accommodate the unique information creation and access needs of users. While limitless storage and technological obsolescence may be surmountable challenges, appraisal continues to be a necessary component of this preservation enterprise. Macro-appraisal—a top-down functional assessment of an organization’s high-level decision making that defines the enduring value of specific bodies of documentary evidence of these creative or administrative processes—is used to facilitate the management of diverse bodies of born-digital records in archives and special collections.     

Model selection for covariance structures analysis in nursing research

Covariance structures analysis is often used in nursing research to appraise statistical models reflecting complex human health processes. The model selection approach in covariance structures analysis is designed to select the "best" model from a specified set of theoretically defensible, competing alternatives, all of which are viewed as approximations. Model selection criteria explicitly incorporate both model misfit in the population and sampling error to evaluate the set of models. The result is that interpretability of model parameters and goodness-of-fit are enhanced simultaneously. Relative merits of the model selection approach are identified in light of technical concerns, parsimony, and use of scientific theory in nursing.     

Cloning of human cDNA encoding a novel heptahelix receptor expressed in Burkitt's lymphoma and widely distributed in brain and peripheral tissues

Using PCR with degenerate primers and screening of a human B-cell lymphoblast cDNA library, a full-length cDNA encoding a 375-amino-acid protein was isolated. It contains seven regions of hydrophobic amino acids probably representing membrane-spanning domains of a novel heptahelix receptor, tentatively named CMKRL2. It shows nearly 30% overall identity with the high-affinity IL8 receptor and similar degree of homology with other chemoattractant receptors, including the "fusin" coreceptors for HIV1. Measurements of various transduction pathways following application of a panel of chemokines to transfected cells failed to evoke any reproducible response. Although the natural ligand for CMKRL2 could, thus, not be identified, receptor expression in spleen and lymph nodes as well as in Burkitt's lymphoma (irrespective of EBV status) supports a functional role in activated B-cells. Receptor message was ubiquitously distributed in normal peripheral tissues and CNS, suggesting that CMKRL2 is expressed in widespread cell populations, such as macrophages and neuroglia.     

Molecular pharmacology of voltage-dependent calcium channels

Voltage-dependent Ca2+ channels serve as the only link to transduce membrane depolarization into cellular Ca(2+)-dependent reactions. A wide variety of chemical substances that have the ability to modulate Ca2+ channels have been demonstrated both for their clinic utility and for importance in elucidating the molecular basis of various biological responses. Recently, introduction of molecular biology to pharmacology has brought a great deal of information about the molecular basis of drug action in Ca2+ channels. In this review, we attempt to overview recent progress in understanding the interactions between Ca2+ channels and their blockers, namely Ca2+ antagonists, from a molecular and structural point of view.     

Development of a Synthetic Skin Simulant Platform for the Investigation of Dermal Blistering Mechanics

Excessive frictional loading to the skin often results in the formation of blisters, due to the transmission of shear loading to the interfaces between dermal cell strata. The consequences of blistering range from mild discomfort to serious infection. In some patients, such as those disposed to epidermolysis bullosa or neuropathic diabetes, blisters can severely degrade life quality. Investigation of environmental and application parameters that affect blister formation has occurred primarily as a qualitative, observational pursuit on human subjects, which has often led to confounding of data and lack of repeatability. The authors have developed a Synthetic Skin Simulant Platform (3SP) that reproduces the mechanical behavior of human skin when exposed to tribological loading. The platform is an assembled construct of bonded elastomeric layers that act as surrogates for the epidermis, basement membrane, dermis, and subdermal structure. Epidermal (top layer) materials are typically silicone or polyurethane films with a friction coefficient akin to human skin, while sublayers display mechanical properties similar to their anatomical analogs. Blistering is evident optically by examining the separation voids formed after applying shear loads to the epidermal layer. The 3SP has been used in a two-axis pin-on-flat tribometer with a stainless steel indenter to study the normal load and friction coefficients encountered at the onset of frictional blistering. The 3SP allows for modulation of friction coefficient, interfacial adhesion strength, and subdermal stiffness for investigation of blistering damage to various anatomical sites. Experimental results have been compared to human test data and have shown that the 3SP provides the potential to make significant advances with respect to skin tribology research.