Papers by Kerry Karukstis
Biochimica Et Biophysica Acta - Bioenergetics, May 1, 1987
ABSTRACT
Biochimica Et Biophysica Acta - Bioenergetics, 1988
ABSTRACT
This chapter discusses the concept of equilibrium for solutions and metal complex ions. It addres... more This chapter discusses the concept of equilibrium for solutions and metal complex ions. It addresses several issues, such as a fizzing action that occurs when an antacid tablet dissolves in water. The effervescence of an antacid tablet in water is the key to the effectiveness of the antacid. Two familiar antacids, such as Alka-Seltzer and Bromo Seltzer contain sodium bicarbonate or baking soda—NaHCO 3 . The bicarbonate ion reacts with citric acid, another ingredient of the product, to produce carbonic acid, H 2 CO 3 . In solution, carbonic acid decomposes to yield water and gaseous carbon dioxide, CO 2 , the same gas in carbonated beverages and champagne. The fizz generated when the tablet dissolves is simply the CO 2 bubbles coming out of solution. The chapter also discusses the functioning of the antidotes for cyanide poisoning, the chemical action of unclogging drains with household products, use of sequestrants in processed food items, and so on.
This chapter addresses several issues related to ionic compounds. One of the issues is what “desi... more This chapter addresses several issues related to ionic compounds. One of the issues is what “desiccants” are and why they are in packaged products. The advanced circuitry in electronic devices can malfunction in humid environments. Moisture can reroute and even short circuit electric signals, impairing the operation of electronic equipment. Manufacturers recognize that moisture can adversely affect their products and therefore, include small packets of “desiccant” to control the moisture levels during shipping and storage. A desiccant is a porous, solid, drying agent or hydrating agent that attracts moisture from the atmosphere and acts by retaining those particles of water on its surface or in the pores of the desiccant. Both synthetic materials and naturally occurring minerals function as desiccants, including dehydrated gypsum, calcinated lime, and a type of clay. Additionally, a myriad of other products benefit from the application of desiccants, including food, pharmaceuticals, shoes and other leather articles, laboratory equipments and hygroscopic chemicals, books and rare manuscripts, museum and historical artifacts, paintings and valuable art objects, films, heating aids, and stamps.
Journal of magnetic resonance, Apr 1, 1983
Recent studies in our laboratory have demonstrated a successful technique for determining preferr... more Recent studies in our laboratory have demonstrated a successful technique for determining preferred conformations in simple aliphatic a-and @-formyloxy radicals, *C(XI)(X2)OCH0 and-C(X,)(X,)C(X~)(X@CHO, respectively, using the results of extensive INDO-MO calculations and liquid-phase, experimental measurements of EPR long-range formyl-proton couplings in these species. The present paper extends this type of study by way of an INDO investigation of a series of a-acetoxy radicals, namely,. CH20C(0)CHx, * CWCfW'WKH,,. CH(CH,CH,)OC(0)CH3,-CH(CH(CH&)-OC(0)CH3,. CH(CH20H)OC(0)CH,,-CH(CH2NH2)0C(0)CHj, and-C(CH,),OC(O)-CHr, for which experimentally determined EPR couplingconstant data are available, and confirms that the b-CH acetyl-proton couplings observed experimentally can be sensitive probes of radical stereochemistry. Specifically, this present study predicts and verifies that, for these radicals, the variations in the size of the experimentally determined &CH acetyl-proton coupling found to result from alterations in the nature of the substitution at the radical center arise from the accompanying changes in radical conformation. Furthermore, the preferred conformations of these cY-acetoxy radicals found in this INDO investigation are in general agreement with similarly determined conformations for structurally analogous-C(X,)(X,)OCHO radicals.
Journal of Chemical Education, Sep 1, 2005
Biochimica Et Biophysica Acta - Bioenergetics, Jul 1, 1984
The detailed process of excitation transfer among the antenna pigments of the red alga Porphyra p... more The detailed process of excitation transfer among the antenna pigments of the red alga Porphyra perforata was investigated by measuring time-resolved fluorescence emission spectra using a single-photon timing system with picosecond resolution. The fluorescence decay kinetics of intact thalli at room temperature revealed wavelength-dependent multi-component chlorophyll a fluorescence emission. Our analysis attributes the majority of chlorophyll a fluorescence to excitation originating in the antennae of PS II reaction centers and emitted with maximum intensities at 680 and 740 nm. Each of these fluorescence bands was characterized by two kinetic decay components, with lifetimes of 340-380 and 1700-2000 ps and amplitudes varying with wavelength and the photochemical state of the PS II reaction centers. In addition, a small contribution to the long-wavelength fluorescence band is proposed to arise from chlorophyll a antennae coupled to PS I. This component displays fast decay kinetics with a lifetime of approx. 150 ps. Desiccation of the thalli dramatically increases the contribution of this fast decay component.
The Journal of Physical Chemistry, Mar 1, 1995
... Kerry K. Karukstis," Marie Y. Kao, Daniel A. Savin, Rachel A. Bittker, Karla... more ... Kerry K. Karukstis," Marie Y. Kao, Daniel A. Savin, Rachel A. Bittker, Karla J. Kaphengst, Chitoh M. Emetarom, Naomi R. Naito, and Dawn Y ... Decreases in the Soret region between 430 and 475 nm and in the peak at 675 nm indicate a mutual shading of chlorophyll pigments ...
Journal of Colloid and Interface Science, Jul 1, 1998
The system of methyl orange and the cationic alkyltri-The spectral signature of the azo dye methy... more The system of methyl orange and the cationic alkyltri-The spectral signature of the azo dye methyl orange (MO) exhibits methylammonium bromide (C n TAB) surfactants, particua considerable sensitivity to the polarity of the dye's environment. larly cetyltrimethylammonium bromide (CTAB, n Å 16), We have used this dependence of absorption wavelength on microenhas been the focus of numerous spectroscopic studies (1, 3vironment to investigate the 1:1 ion pair complexes formed from 12). These investigations have revealed several key changes electrostatic interaction of a series of cationic alkyltrimethylammonin the absorption spectra of aqueous solutions of methyl ium bromide (C n TAB) detergents with the anionic organic probe in orange as surfactant is added. Initially, a decrease in the aqueous solution. At surfactant concentrations far below the critical absorbance of free methyl orange in neutral solution at 463 micelle concentration, MO shifts in absorbance l max from 462 nm in nm is accompanied by a new absorption band at 375 nm for aqueous solution to 367-377 nm upon complex formation. Nonlinear least-squares deconvolution of the absorbance spectra reveals a pre-those [C n TAB] values below the critical micelle concentraviously unreported significant blue shift in l max with increasing surtions (cmc) (9). A slight dependence of the l max of this factant alkyl chain length. Our time-dependent spectrophotometric new absorption band on the surfactant tail length has been studies of the MO-C n TAB complex systems reveal, also for the first observed (377 nm for n Å 12 and 375 nm for n Å 16). On time, that a subsequent spectral shift to shorter wavelengths (l max Å further addition of surfactant at concentrations leading to 348-350 nm) occurs for those alkyl chain lengths greater than n Å micelle formation, the absorption l max of MO shifts to 431 14. These observations are consistent with an aggregation of the nm, independent of alkyl chain length. surfactant-dye pair after initial complex formation. Increased hy-The 375-nm absorption band at surfactant concentrations drophobic interaction of the azo ring of the probe with additional below the cmc is attributed to 1:1 MO-surfactant ion pairs. neighboring surfactant alkyl chains to achieve a final equilibrium The electrostatic interaction of the MO-surfactant ion pair state is hypothesized to account for the MO absorbance spectral shift. and the change in the degree of water hydration of MO have
This chapter provides an introduction to the technique of computerized axial tomography (CAT). Th... more This chapter provides an introduction to the technique of computerized axial tomography (CAT). This technique assists medical examiners in viewing the internal organs of a body. In a CAT scan, cross-sectional images are generated using X-rays directed through the body, using a rotating tube. X-rays not absorbed by the body reach a radiation detector, where the signals are integrated to produce an image that assesses the density of tissues at various locations. X-rays are absorbed differentially. Denser objects, such as bones, absorb X-rays extensively; and soft tissues, such as blood vessels, absorb relatively few X-rays. Thus, bones appear as light areas on the image and soft tissues as dark regions. To create the images in CAT scans, contrast media are often ingested or injected into the body. Barium- and iodine-based materials are selected for contrast media. These media highlight the areas of the body being scanned as a consequence of the inability of X-rays to penetrate these substances.
Journal of Chemical Education, Mar 1, 2008
Physical Chemistry Chemical Physics, 2015
Please note that technical editing may introduce minor changes to the text and/or graphics, which... more Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.
Elsevier eBooks, 2003
This chapter deals with several issues related to organic reactions and classes of organic compou... more This chapter deals with several issues related to organic reactions and classes of organic compounds. The issues are provided with the chemical basics and chemical details. One of the issues dealt with is the elimination of skunk odor. To deodorize a pet sprayed by a skunk, the noxious compound must be converted to an odorless one. By a chemical conversion of a thiol to another class of compound, the disagreeable skunk scent can be removed. Another issue dealt with is the thief detection powder. These powders are designed to apply to the surface of an object likely to be stolen such as cashboxes, cash, or sensitive documents. Alternatively, the powder may be applied to doorknobs or tools to detect entry or use. When the powder comes in contact with the skin, a reagent in the powder reacts with the body's amino acids to create a highly visible long-lasting purple-colored stain. While the stain will not immediately wash off the skin, the color will gradually rub off after about a day. Increasingly law enforcement agencies, banks, businesses, corporate offices, and concerned citizens are using detection powders to trap thieves.
Biochimica Et Biophysica Acta - Bioenergetics, Dec 1, 1984
The fast fluorescence decay kinetics of two photosynthetic mutants of corn (Zea mays) have been c... more The fast fluorescence decay kinetics of two photosynthetic mutants of corn (Zea mays) have been compared with those of normal corn. The fluorescence of normal corn can be resolved into three exponential decay components of lifetime 900-1500 ps (slow), 300-500 ps (middle) and 50-120 ps (fast), the yields of which are affected by light intensity and Mg 2+ levels. The Photosystem II-(PS II)-defective mutant hcf-3 has similar decay lifetimes (approx. 1200, 450 and 100 ps) but is not affected by light intensity, reflecting the absence of PS I1 charge recombination. However, yields do respond to Mg 2+ in a fashion typical of normal corn, which may be correlated with the presence of normal levels of light-harvesting chlorophyll a + b complex (LHCP). The PS I mutant hcf-50 also shows three-component decay kinetics. In conjunction with the results on the LHCP-deficient mutant of barley presented in a recent paper (Karukstis, K.K. and Saner, K. (1984) Biochim. Biophys. Acta 766, 148-155), these data suggest that the slow component of normal chloroplasts is kinetically controlled by the decay processes of the LHCP and that the energy comes from one of two sources: (a) charge recombination in the reaction centre or (b) energy transferred within or between LHCP units only. The fast component appears to originate from both PS I and PS II. The complex response of the middle component to cations and light intensity, and its presence in all of the mutants, suggests that it also may have multiple origins.
Journal of Physical Chemistry B, Sep 17, 1998
Our investigations seek to illustrate the use of fluorescence spectral deconvolution to character... more Our investigations seek to illustrate the use of fluorescence spectral deconvolution to characterize multiple partitioning sites for aromatic chromophores within aqueous and reverse micelles. The spatial distribution of solutes within micellar systems is dictated by a ...
Circulation, Nov 26, 2002
Background-Restenosis is a serious complication of coronary angioplasty that involves the prolife... more Background-Restenosis is a serious complication of coronary angioplasty that involves the proliferation and migration of vascular smooth muscle cells (VSMCs) from the media to the intima, synthesis of extracellular matrix, and remodeling. We have previously demonstrated that tissue factor-targeted nanoparticles can penetrate and bind stretch-activated vascular smooth muscles in the media after balloon injury. In the present study, the concept of VSMC-targeted nanoparticles as a drug-delivery platform for the prevention of restenosis after angioplasty is studied. Methods and Results-Tissue factor-targeted nanoparticles containing doxorubicin or paclitaxel at 0, 0.2, or 2.0 mole% of the outer lipid layer were targeted for 30 minutes to VSMCs and significantly inhibited their proliferation in culture over the next 3 days. Targeting of the nanoparticles to VSMC surface epitopes significantly increased nanoparticle antiproliferative effectiveness, particularly for paclitaxel. In vitro dissolution studies revealed that nanoparticle drug release persisted over one week. Targeted antiproliferative results were dependent on the hydrophobic nature of the drug and noncovalent interactions with other surfactant components. Molecular imaging of nanoparticles adherent to the VSMC was demonstrated with high-resolution T 1-weighted MRI at 4.7T. MRI 19 F spectroscopy of the nanoparticle core provided a quantifiable approach for noninvasive dosimetry of targeted drug payloads. Conclusions-These data suggest that targeted paramagnetic nanoparticles may provide a novel, MRI-visualizable, and quantifiable drug delivery system for the prevention of restenosis after angioplasty. (Circulation. 2002;106:2842-2847.
Journal of Chemical Education, Sep 1, 2008
Journal of magnetic resonance, Apr 1, 1981
In aqueous solution at about 25°C simple aliphatic formate radicals of general formula *C(X,)(X,)... more In aqueous solution at about 25°C simple aliphatic formate radicals of general formula *C(X,)(X,)C(XJ(X,)OCHO, where an (X-) group is an H-or a simple alkyl substituent such as CH,-, generally display 6-CH formyl-proton couplings. The size of these couplings depends on the identity and the degree of substitution of the (X-) groups. An earlier INDO-MO-SCF study of the radical *CH,CH,OCHO attributed this dependence of the observed upward trend in the experimental &CH formyl-proton coupling with increasing substitution at C, to more restricted rotation about the (C,-C,J bond and assigned the origin of the observed fall in the experimental &CH formyl-proton coupling with increasing substitution at Cp to an enhanced favoring of the s-cis conformation over the s-tram. The present paper is an extension of this earlier work, reporting the results of a comprehensive INDO-MO-SCF study of the P-formyloxy radicals l C(CH,),CH,OCHO, *CH(CH,)CH,OCHO, .CH(CH,OH)-CHzOCHO, *CH(CH,NH,)CH,OCHO, .CH,CH(CH,)OCHO, and *CH,C(CH,),-OCHO. The results of the present study confirm the tentative conclusions of the earlier calculations that the observed dependence of the formyl-proton couplings on the nature and degree of substitution at C, and Cp arises from the accompanying changes in radical conformation. Furthermore, by examining the INDO data in comparison with experimentally observed formyl-proton couplings, we have been able to assign preferred radical conformations for all members of the * C(X,)(X,)C(X,)(X,)OCHO series, in general agreement with the known conformational preferences of the parent formate molecules, HC(X,)(X,)-C(X,)(X,)-OCHO.
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Papers by Kerry Karukstis