Physical Chemistry

One of the most frequent side effects due to the use of ciprofloxacin is a gastrointestinal disorder. Generally, in order to overcome the side effects of the Gastro Intestinal Track (GIT), the drug is given after meals (provided 15-30 minutes after meals). Unfortunately the present of food in gaster can significantly decrease maximum concentration (Cmax) of ciprofloxacin. The aim of this study was to determine the effect of sucralfate suspension that containing alumunium (Al3+) on the absorption of oral ciprofloxacin HCl. The effects of 0.47 mL/kg body weight doses of sucralfate suspension which is containing polyvalent cations, aluminum sucrose octa sulfate on the absorption of oral ciprofloxacin HCl before a single 23 mg/kg body weight doses were investigated in 6 rabbit subjects, randomized, cross over and single blind study. The 6 rabbits were enrolled in two studies. Each subject got single ciprofloxacin HCl administration as a control treatment. Treatments that were evaluated included the administration of sucralfate with single dose of ciprofloxacin HCl concomitantly (treatment 1) and the administration of sucralfate 2 hours before ciprofloxacin HCl administration (treatment 2). The absorption parameters of ciprofloxacin HCl were determined by spectrofluorometric method using time to reach maximum concentration (tmax), Cmax and area under curve (AUC) parameters. In control treatment, the average value of Cmax, tmax, and AUC0-360 were 1.34 µg/mL ± 26.15%, 160.78 minutes ± 5.85% and 337.06 µg minutes/mL ± 14.40%. In treatment 1, the average value of Cmax, tmax, and AUC0-360 were 0.68 µg/mL ± 15.49%, 420.66 minutes ± 25.49% and 277.13 µg.minutes/mL ± 12.25%, and in treatment 2 were 0.95 µg/mL ± 18.54%, 284.93 minutes ± 15.44% and 309.75 µg.minutes/mL ± 11.71%. Statistical analysis used in this study was one-sided paired t test (α = 0.05). On the basis of these findings, ciprofloxacin HCl and sucralfate should not be administered concomitantly, but normal kinetics are restored by administering the drug 2 hours before ciprofloxacin HCl. Andrographis paniculata extract suppressed cancer cell growth by decreased cell proliferation and increased apoptosis.

We report the first use of synchrotron radiation, continuously tunable from 8 to 15 eV, for
flame-sampling photoionization mass spectrometry !PIMS". Synchrotron radiation offers important
advantages over the use of pulsed vacuum ultraviolet lasers for PIMS; these include superior
signal-to-noise, soft ionization, and access to photon energies outside the limited tuning ranges of
current VUV laser sources. Near-threshold photoionization efficiency measurements were used to
determine the absolute concentrations of the allene and propyne isomers of C3H4 in low-pressure
laminar ethylene–oxygen and benzene–oxygen flames. Similar measurements of the isomeric
composition of C2H4O species in a fuel-rich ethylene–oxygen flame revealed the presence of
substantial concentrations of ethenol !vinyl alcohol" and acetaldehyde. Ethenol has not been
previously detected in hydrocarbon flames. Absolute photoionization cross sections were measured
for ethylene, allene, propyne, and acetaldehyde, using propene as a calibration standard. PIE curves
are presented for several additional reaction intermediates prominent in hydrocarbon flames.

Some difficulties on a sampling of gaseous glyoxal using DNPH-silica cartridge were discussed, and an alternative sampling procedure was
proposed. When glyoxal was sampled using the cartridge, it partially formed mono-hydrazone with various degrees, whereas it was quantitatively
converted into its bis-hydrazone when sample gas was directly bubbled into a DNPH acidic solution. Additionally, glyoxal polymerized on the inner
wall of the system during trapping to the silica cartridge. We found that the polymerization of glyoxal was effectively suppressed by dissolving
glyoxal into methanol under reduced pressure; glyoxal in methanol readily reacted with DNPH in a hydrochloric acid solution and gave bishydrazone
derivative, without any interference of methanol and any formation of mono-hydrazone derivative. When glyoxal was sampled by the
proposed method, 102% of recovery was obtained, whereas it was reduced to 92.7% when the trapped glyoxal was dissolved into methanol under
atmosphere.

The BP Deepwater Horizon oil spill was detrimental to the prosperity of marine and wildlife habitats, as well as the fishing and tourism industry in the surrounding region. Oil spills can also indirectly affect the economies of countries outside the region, specifically through the spread of toxins harmful to aquatic life. A reversed-phase high-performance liquid chromatographic method (HPLC) with UV detection is developed and validated for the quantitative determination of pollutants in surface oil exposed to sunlight. Octanal, hexanal, and propionaldehyde are the three waste products targeted in this study. These aldehydes have specific negative impacts on marine wildlife, such as long term cardiotoxicity in fish and liver dysfunction in mammals. Because aldehydes and ketones are considered a waste product in aquatic environments, this long-term study was conducted to identify and quantify the formation of aldehydes in emulsified crude oil and seawater by high-performance liquid chromatography (HPLC) and solar simulation. Oil samples collected from BP’s Surrogate Macondo Well were irradiated by solar simulator over six, twelve, and eighteen hour periods. The aqueous solution from beneath the oil was then pulled, derivatized with dinitrophenylhydrazine (DNPH), and analyzed by HPLC with UV detection to be compared to the standard chromatograms generated for propionaldehyde, octanal, and hexanal. Chromatogram results from the eighteen hour irradiated BP Surrogate oil indicated that aldehydes were present after exposure to sunlight, and within the range of the aldehyde standards used based on their carbon chains. The procedure developed in this research will allow EPA and bioremediation organizations to identify toxins forming as photoproducts in an oil spill, and treat affected marine ecosystems accordingly.

The Dirac equation electron is modeled as a helically circulating charged photon, with the longitudinal component of the charged photon's velocity equal to the velocity of the electron. The electron's relativistic energy-momentum equation is satisfied by the circulating charged photon. The relativistic momentum of the electron equals the longitudinal component of the momentum of the helically-circulating charged photon, while the relativistic energy of the electron equals the energy of the circulating charged photon. The circulating charged photon has a relativistically invariant transverse momentum that generates the z-component of the spin  of a slowly-moving electron. The charged photon model of the electron is found to generate the relativistic de Broglie wavelength of the electron. This result strongly reinforces the hypothesis that the electron is a circulating charged photon. Wave-particle duality may be better understood due to the charged photon model—electrons have wavelike properties because they are charged photons. New applications in photonics and electronics may evolve from this new hypothesis about the electron.

The Middle to Late Pleistocene spring site of Florisbad, South Africa, is the name site of the Florisian Land Mammal Age (LMA), and it has produced a large collection of fossil bones from different sedimentary contexts. The largest of these faunal assemblages derives from vertically intrusive dormant spring vents and is taphonomically distinct from specimens associated with a Middle Stone Age occupational horizon. The Florisbad faunal assemblages include several extinct and extant animal species, mainly grazing ungulates that represent a highly productive open grassland environment. The Florisian LMA was characterized by substantially wetter conditions compared to the Holocene. Geological evidence at Florisbad and the characteristic occurrence of water-dependent species, such as lechwe, waterbuck, hippopotamus and a variety of water birds, reflect the presence of a vast intermittent paleo-lake forming during the wet phases of the Middle and Late Pleistocene. During dry phases, the area of spring activity was not inundated and provided a suitable habitat for both humans and animals. Bones collected from different sedimentary contexts exhibit a number of post-depositional alterations that reflect specific diagenetic processes, which led to fossilization. Two contrasting hypotheses regarding these processes, based on morphological studies of bones and groundwater chemistry, were proposed in the past. The first identified spring water as a major fossilization agent, whereas the second saw it as a medium conducive to bone dissolution. Using Fourier Transform infrared spectrometry (FTIR) and micro-spectrometry (µFTIR), we determined the mineralogical composition of these bones. We show here that specimens from inactive paleo-spring vents are characterized by the formation of carbonate fluorapatite on the outer surface of cortical bone, and locally exhibit authigenic calcite crystals, as opposed to bones collected from non-spring contexts at the site. The nucleation of carbonate fluorapatite is linked to the high fluoride content of the alkaline spring water, thus confirming its key role in the fossilization process of bones recovered from paleo-spring vents. Therefore, our results support the first of the two hypotheses advanced in the past.

The unsymmetrical and symmetrical azines prepared by condensation of benzophenone hydrazone with (di)aldehydes with thiophene rings were reported in this study The structures of obtained compounds were characterized by FTIR, 1H NMR, and 13C NMR spectroscopy as well as elemental analysis. Optical, electrochemical, and thermal properties of azines were investigated. The unsymmetrical azine with bithiophene unit exhibited liquid crystalline properties as was detected by DSC and POM experiments. All compounds are electrochemically active, however, only azines with bithiophene structure undergo reversible reduction process as was found in cyclic and differential pulse voltammetry (CV and DPV) studies. Additionally, the electronic properties, that is, orbital energies and resulting energy gap were calculated theoretically by density functional theory (DFT). The photovoltaic properties of two azines as active layer in organic solar cells at the configuration ITO/PEDOT:PSS/active layer/Al under an illumination of 1.3 mW/cm2 were studied. Active cell layers blends of poly 3-hekxylthiophene (P3HT) or poly 3-butylthiophene (P3OT) with azines were applied. The device comprising P3HT with symmetrical azine containing bithiophene unit showed the highest value of power conversion efficiency (0.82%). To the best of our knowledge, the azines are very seldom considered as potential compounds in active layer in bulk heterojunction (BHJ) solar cells.

Rapid proton migration is a key process in hydrocarbon photochemistry. Charge migration and subsequent proton motion can mitigate radiation damage when heavier atoms absorb X-rays. If rapid enough, this can improve the fidelity of diffract-before-destroy measurements of biomolecular structure at X-ray-free electron lasers. Here we study X-ray-initiated isomerization of acetylene, a model for proton dynamics in hydrocarbons. Our time-resolved measurements capture the transient motion of protons following X-ray ionization of carbon K-shell electrons. We Coulomb-explode the molecule with a second precisely delayed X-ray pulse and then record all the fragment momenta. These snapshots at different delays are combined into a ‘molecular movie’ of the evolving molecule, which shows substantial proton redistribution within the first 12 fs. We conclude that significant proton motion occurs on a timescale comparable to the Auger relaxation that refills the K-shell vacancy.

The kinetics of the oxidation of norfloxacin by diperiodatocuprate(III) in aqueous
alkaline medium has been studied spectrophotometrically at 300 K and at constant
ionic strength of 0.20 mol dm−3. The oxidation products were identified by LC–ESI–MS
technique and other spectral studies. The stoichiometry was found to be 1:2 ([NOR]:[DPC].
The active species of DPC is understood to be as monoperiodatocuprate(III). A suitable
mechanism was proposed on the basis of experimental results. The reaction constants
involved in the different steps of the reaction mechanism were calculated. The activation
parameters with respect to the slow step of mechanism were determined and discussed