Seminar Speakers 2014 - Chemistry Department

Department Seminar Speakers

 

2014

 

  • Dr. Daniele Musumeci (York College, CUNY)
  • November 6, 2014
  • Title: "Surface Crystal Growth and Stabilization of Amorphous Pharmaceutical Solids"
  • Abstract: Glasses are amorphous materials that combine the mechanical stability of solids with the microscopic spatial uniformity of liquids, making them ideal for many applications, including electronics, bio-preservation and drug delivery. Amorphous solids, however, are inherently unstable, and can crystallize over time, sometimes surprisingly fast. Recent studies have discovered that as organic liquids are cooled to become glasses, crystal growth at the free surface can be substantially faster than in the interior. This phenomenon is uncommon for inorganic materials and it is generally terminated as the glasses are heated to become liquids. We have applied scanning electron microscopy (SEM) and real-time atomic force microscopy (AFM) to investigate the surface crystal growth on glassy indomethacin (IMC), an anti-inflammatory drug, in the alpha and gamma polymorphs. The high-resolution microscopies provided complete micro-structural details of surface crystal growth. We observed that surface crystals rise hundreds of nano-meters above the amorphous surface as they grow laterally, and are surrounded by depletion zones. Upon heating above the glass transition temperature, the onset of liquid flow embeds upward-growing surface crystals and terminates their growth, but this effect is remarkably mild for the gamma polymorph of IMC. This effect arises because the velocity of liquid flow exceeds the growth front velocity, causing the wetting and embedding of upward-growing surface crystals. These findings are important for understanding and predicting the stability of amorphous drugs. During the seminar, we will discuss the educational pathways and the career opportunities provided by the B.S. degree program in Pharmaceutical Science at York College.
none none
none none
none none
none none
none none
none none
none none
none none

  • Dr. Marcel Roberts (John Jay College of Criminal Justice)
  • October 17, 2014
  • Title: "A Lab-On-Chip Approach to Forensic Science"
  • Abstract:A major effect of globalization is the transit of a large amount of travelers through numerous borders. The sheer number of bodies that need to be inspected poses a threat to public and national security. The solution for a non-invasive, expedited and reliable screening of vast numbers of people, calls for the creation of a novel device that can identify an individual but also simultaneously detect the presence of illegal or dangerous substances in their sweat. To solve the dilemma an innovative approach is to use methods devised by engineers for clinical uses and adapt them to serve forensic goals. Lab-On-Chip devices offer a cheap, portable and disposable alternative that can be applied in such situations that require mass screening. In our lab we propose and test various designs geared to detect drugs and explosive in sweat while recording fingerprints.
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none

  • Dr. Robert B. Grubbs (SUNY Stony Brook)
  • October 2, 2014
  • Title: "From Molecules to Macromolecules to Materials: Controlling Structure through Synthesis"
  • Abstract: The control over structure facilitated by modern synthetic techniques enables control over the assembly of molecules and macromolecules in functional materials. We have designed and synthesized several classes of block and star-block copolymers with stimulus-responsive components. These polymers form assemblies with shapes and sizes that are dependent upon specific conditions. For example, we have investigated a range of synthetic systems that are designed to assemble in water into smaller micellar aggregates at low temperatures and larger vesicles at higher temperatures. The structural shifts in these systems under specific conditions will be discussed. A number of factors, including block size and extent of interblock interactions, appear to be important in controlling transformation rate. We will describe the design of these and other systems and our efforts to better understand the behavior of the resulting materials.
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none

  • Dr. Robert Q. Topper (Cooper Union)
  • September 17, 2014
  • Title: "Computational Studies of Nanoparticles"
  • Abstract: The reaction between ammonia and hydrogen chloride to form solid NH4Cl has been studied for many years, serving as a prototype system for an improved understanding of acid-base chemistry. Recently, studies have found that aerosols containing NH4Cl particles form atmospherically in polluted marine and coastal environments. This motivated us to try to predict the relative stabilities of differently-sized NH4Cl nanoparticles in the gas phase. In this lecture we will discuss our methods and findings, as well as our current work on other ammonium halides.
none none
none none
none none
none none
none none

  • Dr. Ronald Breslow (Columbia University)
  • April 3, 2014
  • Title: "How Did It All Gget Started? Prebiotic Chemistry. The Origin of Terrestrial Homochirality in Amino Acids and Nucleosides"
  • Abstract: Work on artificial enzymes that perform the synthesis of amino acids from ketoacids led us to examine the properties of alpha-methyl amino acids. Recently these have been identified as components of carbonaceous chondritic meteorites such as the one that landed near Murchison Australia in the last century. These unusual amino acids arrive with excesses of stable chirality, all of the L configuration, and we will describe how they could have been formed. We showed that they can generate normal amino acids under credible prebiotic conditions, and with some chirality transfer. We also showed that the modest chirality that resulted could be amplified to high enantioexcesses of normal L aminoacids, using either thermodynamic or kinetic processes. We have shown that we can also amplify modest excesses of D nucleosides to high enantioexcesses by related processes. Finally, we have also shown the likely origin of D sugars. The resulting amino acids, sugars, and nucleosides can then be suitable materials for the creation of life.
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none
none none

  • Prof. Pete Diaczuk (John Jay College of Criminal Justice, CUNY)
  • March 21, 2014
  • Title: "Chemistry in Crime Scene Reconstruction"
  • Abstract: Crime scene reconstruction can present very difficult and complex challenges to the forensic scientist. Correctly interpreting the crime scene to reconstruct the events that took place during the act of a crime can provide both useful leads in the investigative stage and important facts for the jury to consider during the adjudicative stage. The proper interpretation of these crime scene events is not a trivial task; however, the forensic scientist must often rely on many aspects of their education as the scene is reconstructed. A critical assessment of the evidence can often be aided by the application of chemistry and established chemical reactions as a hypothesis is being developed. This presentation will highlight some of the useful chemistry that a forensic scientist might employ in a crime scene reconstruction.
none none
none none
none none
none none
none none
none none
none none
none none

  • Dr. Yolana A. Small (York College, CUNY)
  • March 6, 2014
  • Title: "Water Splitting Chemistry Using Photocatalytic Semiconductor and Molecular Co-Catalysts"
  • Abstract: From the energy demands of the modern age and the need to preserve environmental quality, there is a current push towards finding renewable energy technology. Fuel cells are one such target because the energy source can be garnered from solar power and the naturally abundant water supply. Water oxidation and hydrogen production are fundamental steps in the so-called water splitting process. The availability of photo-generated excitons in semiconductor materials facilitates water oxidation and proton reduction through an unknown mechanism. Efficient photoanodes for water oxidation are crucial for any scheme to convert the energy in sunlight to fuels. We utilize computational methods, based on density functional theory, to obtain a fundamental, atomistic understanding of water oxidation mechanisms in photocatalytic semiconductors. To aid our understanding of hydrogen production and oxidation, we turn to hydrogenase enzymes which catalyze both processes efficiently. Aiming to design hydrogenase-like catalysts with equal efficiency, computational methods are applied to explore features of molecular catalysts and evaluate their contributions to overall catalytic ability.
none none
none none
none none
none none

  • Dr. Wayne E. Jones (SUNY at Binghamton)
  • February 7, 2014
  • Title: "Fluorescent Conjugated Polymer Chemosensors for the Environment Based on Inorganic-Organic Hybrid Structures"
  • Abstract: Developing chemosensory devices selective for transition metals and other pollutants represents a critical need for the environmental community. Fluorescent conjugated polymer chemosensors have several advantages over small molecule sensors due to their high sensitivity, processibility, and ease of modification. Previously, our group has synthesized a series of fluorescent polymerchemosensors with a poly[p-(phenyleneethylene)-alt-(thienyleneethynylene)](PPETE) conjugated backbone. The transition metal loading dependence of these materials provides fundamental information regarding the role of energy transfer in the fluorescent chemosensor quenching mechanism. Recently, this work has been extended by addition of a N,N,N’-trimethylethylenediamino receptor group which undergoes photoinduced electron transfer (PET) to the polymer exciton. Upon binding to analytes such as protons or some transtion metal cations, the PET process is disabled and the emission from the polymer is enhanced. This system has been found to be particularly sensitive to Hg2+ ions that cause the fluorescence of the polymer to increase by a factor of ? 2.7. Synthesis, characterization and photophysical behavior of this polymer will be discussed as well as its application to future “Turn-on” sensor designs.
none none
none none
none none
none none
none none
none none
none none
none none
none none

  • Dr. Wayne E. Jones (SUNY at Binghamton)
  • February 6, 2014 (The LI-ACS Seminar)
  • Title: "Inorganic/Organic Hybrid Structures for Photovoltaics: Low cost roll to roll processing of solar cells"
  • Abstract: The preparation of competitive solar energy conversion technologies has been limited by the cost and efficiency of modern materials. We have been developing new approaches to layered inorganic/organic photovoltaic materials on flexible substrates. The flexible thin film solar cell is based on a combination of organic bulk heterojunction strategies with semi-conductor nanostructures. These hybrid inorganic/organic systems require development of new materials and processing technologies in order to make them suitable for low cost roll-to-roll manufacturing. Titanium dioxide nanoparticles, conducting polymer films such as polyethylenedioxythiophene (PEDOT) and polyaniline (PANI), and self-assembled layered materials of laponite have been prepared on polyethylene terephthalate (PET) substrates. We have also explored alternative transparent conducting electrode layers for flexible substrates including doped ZnO and CVD deposited conducting polymers. In this presentation, we will explore recent advances in the preparation, processing, and testing of these hybrid photovoltaic devices completed at the new Center for Autonomous Solar Power (CASP) and the Center for Advanced Microelectronics Manufacturing (CAMM) at Binghamton University’s Center of Excellence.
none none
none none
none none
none none
none none
none none
none none
none none

Cultural Centers

image description
Kupferberg Holocaust Resource Center and Archives

Using the lessons of the Holocaust to educate current and future generations about the ramifications of unbridled prejudice, racism and stereotyping.

image description
QPAC: Performing Arts Center

QPAC is an invaluable entertainment company in this region with a growing national reputation. The arts at QPAC continues to play a vital role in transforming lives and building stronger communities.

image description
QCC Art Gallery

The QCC Art Gallery of the City University of New York is a vital educational and cultural resource for Queensborough Community College, the Borough of Queens and the surrounding communities.