Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Conducting Polyaniline Filaments in a Mesoporous Channel Host

Abstract: Conducting filaments of polyaniline have been prepared in the 3-nanometer-wide hexagonal channel system of the aluminosilicate MCM-41. Adsorption of aniline vapor into the dehydrated host, followed by reaction with peroxydisulfate, leads to encapsulated polyaniline filaments. Spectroscopic data show that the filaments are in the protonated emeraldine salt form, and chromatography indicates chain lengths of several hundred aniline rings. The filaments have significant conductivity while encapsulated in the channels, as measured by microwave absorption at 2.6 gigahertz. This demonstration of conjugated polymers with mobile charge carriers in nanometer channels represents a step toward the design of nanometer electronic devices.

A conceptual model of perceived customer value in e-commerce: A preliminary investigation

Abstract: This article presents an exploratory study of a conceptual model of perceived customer value in a business-to-consumer e-commerce setting Key precursors of perceived customer value included in the model are valence of on-line shopping experience, perceived product quality, perceived risk, and product price Relationships among these variables (as well as mediating variables) and their relationship to on-line shoppers' value perceptions are explored The theoretical framework proposed in this work expands on previous efforts on perceived customer value by including new variables relevant to an e-commerce setting and by integrating several key variables into one model The preliminary findings lead to several implications © 2003 Wiley Periodicals, Inc

Discovery and Development of Folic-Acid-Based Receptor Targeting for Imaging and Therapy of Cancer and Inflammatory Diseases

Abstract: In order to avoid the toxicities associated with prescription drug use today, we have explored novel methods for delivering drugs selectively to pathologic cells, thereby avoiding the collateral damage that accompanies their uptake by healthy cells. In this Account, we describe our quest for the ideal targeted therapeutic agent. This effort began with a search for ligands that would bind selectively to pathologic cells, displaying no affinity for healthy cells. After identification of an optimal targeting ligand, effort was focused on construction of linkers that would carry the attached drug to pathologic cells with receptors for the selected ligand. In the case of cancer, we exploited the well-characterized up-regulation of folate receptors on malignant cells to target folate-linked pharmaceuticals to cancer tissues in vivo. Drugs that have been linked to folic acid for tumor-selective drug delivery to date include (i) protein toxins, (ii) chemotherapeutic agents, (iii) gene therapy vectors, (iv) oligonucleotides (including small interfering RNA (siRNA)), (v) radioimaging agents, (vi) magnetic resonance imaging (MRI) contrast agents, (vii) liposomes with entrapped drugs, (viii) radiotherapeutic agents, (ix) immunotherapeutic agents, and (x) enzyme constructs for prodrug therapy. Current clinical trials of four folate-linked drugs demonstrate that folate receptor-targeting holds great promise for increasing the potency while reducing toxicity of many cancer therapies. In the course of developing folate-conjugated drugs for cancer, we discovered that folate receptors are also overexpressed on activated (but not resting or quiescent) macrophages. Recognizing that activated macrophages either cause or contribute to such diseases as rheumatoid arthritis, Crohn's disease, atherosclerosis, lupus, inflammatory osteoarthritis, diabetes, ischemia reperfusion injury, glomerulonephritis, sarcoidosis, psoriasis, Sjogren's disease, and vasculitis, we initiated studies aimed at developing folate-conjugated imaging and therapeutic agents for the diagnosis and treatment of such diseases. In very brief time, significant progress has been made towards identification of clinical candidates for targeted treatment of several inflammatory and autoimmune diseases. This Account summarizes the discovery and development of a variety of folate-targeted drugs for the diagnosis and therapy of cancers and inflammatory/autoimmune diseases.

Progress in understanding jointing over the past century

Abstract: Joints are the most common result of brittle fracture of rock in the Earth's crust. They control the physiography of many spectacular landforms and play an important role in the transport of fluids. In its first century, the Geological Society of America Bulletin has published a significant number of papers on joints and jointing. One hundred years ago, there were lively debates in the literature about the origin of joints, and detailed descriptions of joints near the turn of the century catalogued most geometric features that we recognize on joints today. In the 1920s, theories relating joint orientation to the tectonic stress field and to other geologic structures led to a proliferation of data on the strike and dip of joints in different regions. The gathering of orientation data dominated work on joints for the next 50 yr. In the 1960s, key papers re-established the need to document surface textures, determine age relations, and measure relative displacements across joints in order to interpret their origins. At about this time, fundamental relationships from the fields of continuum and fracture mechanics were first used to understand the process of jointing. In the past two decades, we have witnessed an effort to use field data to interpret the kinematics of jointing and to understand the initiation, propagation, interaction, and termination of joints. Theoretical methods have been developed to study the evolution of joint sets and the mechanical response of a jointed rock mass to tectonic loading. Although many interesting problems remain to be explored, a sound conceptual and theoretical framework is now available to guide research into the next century.