ABSTRACT
γ-Valerolactone (GVL) is regarded as a key platform molecule in the production of fine chemicals such as pentenoic acid (PA) from biomass. Although PA is believed to be the key intermediate in solid-acid-catalyzed reactions of GVL, due to subsequent facile decarboxylation reactions further alkene products are formed. Here, by tailoring the acidity of Brønsted acid sites in an aluminophosphate (AlPO) molecular sieve through incorporation of Zn2+ into the framework, we access a new selective and effective catalyst for GVL conversion to PA.
ABSTRACT
It is demonstrated that light elements, including lithium and boron atoms, can take residence in the octahedral (interstitial) site of a Pd lattice by modifying the electronic properties of the metal nanoparticles, and hence the adsorptive strength of a reactant. The blocking of the sub-surface sites to H in the modified materials results in significantly higher selectivity for the partial catalytic hydrogenation of acetylene to ethylene.
Subject(s)
Acetylene/chemistry , Boron/chemistry , Lithium/chemistry , Palladium/chemistry , Catalysis , HydrogenationABSTRACT
We have digitized mammography films of African-American patients treated in the Howard University Hospital Radiology Department and have developed a database using these images. Two hundred and sixty cases totaling more than 5,000 images have been scanned with a high resolution Kodak LS85 laser scanner. The database system and web-based search engine were developed using MySQL and PHP. The database has been evaluated by medical professionals, and the experimental results obtained so far are promising with high image quality and fast access time. We have also developed an image viewing system, D-Viewer, to display these digitized mammograms. This viewer is coded in Microsoft Visual C# and is intended to help medical professionals view and retrieve large data sets in near real time. Finally, we are currently developing an image content-based retrieval function for the database system to provide improved search capability for the medical professionals.
Subject(s)
Black or African American , Breast Neoplasms/diagnostic imaging , Databases as Topic , Hospitals, University , Mammography , District of Columbia , Female , Humans , Medical Records Systems, Computerized , Radiographic Image Interpretation, Computer-AssistedABSTRACT
Severe Acute Respiratory Syndrome (SARS) is a newly described infection affecting, in most individuals, the lungs with progressive severe pneumonia. It is highly contagious and has a high mortality rate. It is unresponsive to antibiotics and the main methods of control involve barrier isolation. Because of these features, early diagnosis is required for control of the disease. Unlike other forms of severe pneumonia, the initial presenting chest radiograph may not disclose the pneumonia. A computer-aided detection system has been developed that marks locations on chest radiographs of minimal areas of pneumonia. It has been tested on a small series of chest radiographs with minimal SARS pneumonia and provided 88% sensitivity with 1.3 false-positive marks per image.